Publications
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Bjørnestad, Synne Arstad; Solbakken, Monica Hongrø; Krokene, Pia; Thiede, Bernd; Hylland, Ketil & Jakobsen, Kjetill Sigurd
[Show all 9 contributors for this article]
(2024).
The Atlantic Cod MHC I compartment has the properties needed for cross-presentation in the absence of MHC II.
Scientific Reports.
14(1).
doi:
10.1038/s41598-024-76225-z.
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Atlantic cod has a peculiar immune system, characterized by the loss of Major Histocompatibility Complex (MHC) class II pathway, and an extreme expansion of the MHC class I gene repertoire. This has led to the hypothesis that some of the MHC I variants have replaced MHC II by presenting exogenous-peptides in a process similar to cross-presentation. In mammals, MHC I loads endogenous antigens in the endoplasmic reticulum, but we recently found that different Atlantic cod MHC I gene variants traffic to endolysosomes. There, they colocalize with Tapasin and other components of the peptide-loading complex, indicating a plausible peptide-loading system outside the endoplasmic reticulum. In this study, we further characterize the identity of the Atlantic cod MHC I compartment (cMIC). We found that, similarly to mammalian MHC II compartment, cMIC contains late endosomal markers such as Rab7, LAMP1 and CD63. Furthermore, we identified Hsp90b1 (also known as grp94) and LRP1 (also known as CD91) as interactors of MHC I by mass spectrometry. As these two proteins are involved in cross-presentation in mammals, this further suggests that Atlantic cod MHC I might use a similar mechanism to present exogenous peptides, thus, compensating for the absence of MHC II.
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Hu, Xian; Jalal, Salma; Yao, Mingxi; Bakke, Oddmund; Margadant, Felix Martin & Sheetz, Michael P.
(2024).
Differential Talin cleavage in transformed and non-transformed cells and its consequences.
Frontiers in Cell and Developmental Biology.
12.
doi:
10.3389/fcell.2024.1430728.
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This study investigates differences in focal adhesion (FA) morphology and Talin cleavage levels between transformed and non-transformed cell lines. Utilizing fluorescently tagged wild-type Talin and Talin mutants with calpain cleavage site mutations, FA structures were visualized. Mutations in different Talin cleavage sites showed varying impacts on FA morphology and distribution across melanoma cell lines (Meljuso, A375P, A2058) and a non-transformed cell line (HFF). Western blot analysis, ratiometric fluorescence intensity-based measurements, and FRAP experiments revealed higher Talin cleavage levels within FAs of transformed cell lines compared to non-transformed cells. Additionally, growth assays indicated that reducing calpain cleavage levels attenuated transformed cell growth. These findings suggest that Talin cleavage level is crucial for FA morphology and assembly, with higher levels observed in transformed cells, influencing their growth dynamics.
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Gopalakrishnan, Ramakrishna Prabhu; Østrøm, Marius Sigurdsson; Skjeldal, Frode Miltzow; Bakke, Oddmund; Bogen, Bjarne & Huszthy, Csaba Peter
(2024).
B Cells With Complementary B Cell Receptors Can Kill Each Other.
European Journal of Immunology.
ISSN 0014-2980.
55(1),
p. 1–13.
doi:
10.1002/eji.202350890.
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Lobos, Natacha; Zulkefli, Khalisah Liyana; McAdam, Martin Berner; Vargas, Pablo; Bakke, Oddmund & Progida, Cinzia
(2023).
Rai14 is a novel interactor of Invariant chain that regulates macropinocytosis.
Frontiers in Immunology.
14,
p. 1–15.
doi:
10.3389/fimmu.2023.1182180.
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Invariant chain (Ii, CD74) is a type II transmembrane glycoprotein that acts as a chaperone and facilitates the folding and transport of MHC II chains. By assisting the assembly and subcellular targeting of MHC II complexes, Ii has a wide impact on the functions of antigen-presenting cells such as antigen processing, endocytic maturation, signal transduction, cell migration, and macropinocytosis. Ii is a multifunctional molecule that can alter endocytic traffic and has several interacting molecules. To understand more about Ii’s function and to identify further Ii interactors, a yeast two-hybrid screening was performed. Retinoic Acid-Induced 14 (Rai14) was detected as a putative interaction partner, and the interaction was confirmed by co-immunoprecipitation. Rai14 is a poorly characterized protein, which is believed to have a role in actin cytoskeleton and membrane remodeling. In line with this, we found that Rai14 localizes to membrane ruffles, where it forms macropinosomes. Depletion of Rai14 in antigen-presenting cells delays MHC II internalization, affecting macropinocytic activity. Intriguingly, we demonstrated that, similar to Ii, Rai14 is a positive regulator of macropinocytosis and a negative regulator of cell migration, two antagonistic processes in antigen-presenting cells. This antagonism is known to depend on the interaction between myosin II and Ii. Here, we show that Rai14 also binds to myosin II, suggesting that Ii, myosin II, and Rai14 work together to coordinate macropinocytosis and cell motility.
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Bjørnestad, Synne Arstad; Solbakken, Monica Hongrø; Jakobsen, Kjetill Sigurd; Jentoft, Sissel; Bakke, Oddmund & Progida, Cinzia
(2023).
Atlantic cod (Gadus morhua) MHC I localizes to endolysosomal compartments independently of cytosolic sorting signals.
Frontiers in Cell and Developmental Biology.
11,
p. 1–15.
doi:
10.3389/fcell.2023.1050323.
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Major histocompatibility complex (MHC) class I and II are crucial for the adaptive immune system because they are involved in peptide presentation to T cells. Until recently, it was believed that MHC genes and their associated immune components had been conserved since their evolutionary emergence in jawed fish. However, sequencing of the Atlantic cod ( Gadus morhua ) genome revealed a loss of MHC class II genes, and an extreme expansion of MHC class I genes. These findings lead to the hypothesis that a loss of the MHC class II pathway coincided with a more versatile use of MHC class I, but so far there is no direct experimental evidence in support of this. To gain a deeper understanding of the function of the expanded MHC class I, we selected five MHC class I gene variants representing five of the six clades identified in previous studies and investigated their intracellular localization in human and Atlantic cod larval cells. Intriguingly, we uncovered that all selected MHC class I variants localize to endolysosomal compartments in Atlantic cod cells. Additionally, by introducing point mutations or deletions in the cytosolic tail, we found that hypothetical sorting signals in the MHC class I cytosolic tail do not influence MHC class I trafficking. Moreover, we demonstrated that in Atlantic cod, tapasin and MHC class I colocalize on endolysosomes suggesting that peptide-loading assistance and stabilization of MHC class I occurs outside the endoplasmic reticulum. Altogether, our results demonstrate that MHC class I from Atlantic cod is sorted to the endolysosomal system, which may indicate that it interacts with exogenous peptides for potential cross presentation.
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Skjeldal, Frode Miltzow; Haugen, Linda Hofstad; Mateus, Duarte Nunes De C; Frei, Dominik Michael; Rødseth, Anna Vik & Hu, Xian
[Show all 7 contributors for this article]
(2021).
De novo formation of early endosomes during Rab5-to-Rab7a transition.
Journal of Cell Science.
ISSN 0021-9533.
134(8).
doi:
10.1242/jcs.254185.
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Rab5 and Rab7a are the main determinants of early and late endosomes and are important regulators of endosomal progression. The transport from early endosomes to late endosome seems to be regulated through an endosomal maturation switch, where Rab5 is gradually exchanged by Rab7a on the same endosome. Here, we provide new insight into the mechanism of endosomal maturation, for which we have discovered a stepwise Rab5 detachment, sequentially regulated by Rab7a. The initial detachment of Rab5 is Rab7a independent and demonstrates a diffusion-like first-phase exchange between the cytosol and the endosomal membrane, and a second phase, in which Rab5 converges into specific domains that detach as a Rab5 indigenous endosome. Consequently, we show that early endosomal maturation regulated through the Rab5-to-Rab7a switch induces the formation of new fully functional Rab5-positive early endosomes. Progression through stepwise early endosomal maturation regulates the direction of transport and, concomitantly, the homeostasis of early endosomes.
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Vestre, Katharina; Persiconi, Irene; Distefano, Marita Borg; Mensali, Nadia; Guadagno, Noemi Antonella & Bretou, Marine
[Show all 12 contributors for this article]
(2021).
Rab7b regulates dendritic cell migration by linking lysosomes to the actomyosin cytoskeleton.
Journal of Cell Science.
ISSN 0021-9533.
134(18).
doi:
10.1242/jcs.259221.
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Lysosomal signaling facilitates the migration of immune cells by releasing calcium to activate the actin-based motor myosin II at the cell rear. However, how the actomyosin cytoskeleton physically associates to lysosomes is unknown. We have previously identified myosin II as a direct interactor of Rab7b, a small GTPase that mediates the transport from late endosomes/lysosomes to the TGN. Here, we show that Rab7b regulates the migration of dendritic cells (DCs) in 1- and 3-dimensional environments. DCs are immune sentinels that transport antigens from peripheral tissues to lymph nodes to activate T lymphocytes and initiate adaptive immune responses. We found that lack of Rab7b reduces myosin II light chain phosphorylation and the activation of the transcription factor EB (TFEB), which controls lysosomal signaling and is required for fast DC migration. Furthermore, we demonstrate that Rab7b interacts with the lysosomal calcium channel TRPML1, enabling the local activation of myosin II at the cell rear. Altogether, our findings identify Rab7b as the missing physical link between lysosomes and the actomyosin cytoskeleton, allowing control of immune cell migration through lysosomal signaling.
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Guadagno, Noemi Antonella; Margiotta, Azzurra; Bjørnestad, Synne Arstad; Haugen, Linda Hofstad; Kjos, Ingrid & Xiaochun, Xu
[Show all 10 contributors for this article]
(2020).
Rab18 regulates focal adhesion dynamics by interacting with kinectin-1 at the endoplasmic reticulum.
Journal of Cell Biology.
ISSN 0021-9525.
219(7),
p. 1–23.
doi:
10.1083/JCB.201809020.
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The members of the Rab family of small GTPases are molecular switches that regulate distinct steps in different membrane traffic pathways. In addition to this canonical function, Rabs can play a role in other processes, such as cell adhesion and motility. Here, we reveal the role of the small GTPase Rab18 as a positive regulator of directional migration in chemotaxis, and the underlying mechanism. We show that knockdown of Rab18 reduces the size of focal adhesions (FAs) and influences their dynamics. Furthermore, we found that Rab18, by directly interacting with the endoplasmic reticulum (ER)-resident protein kinectin-1, controls the anterograde kinesin-1–dependent transport of the ER required for the maturation of nascent FAs and protrusion orientation toward a chemoattractant. Altogether, our data support a model in which Rab18 regulates kinectin-1 transport toward the cell surface to form ER–FA contacts, thus promoting FA growth and cell migration during chemotaxis
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Margiotta, Azzurra; Frei, Dominik Michael; Sendstad, Ingrid Hegnes; Janssen, Lennert; Neefjes, Jacques & Bakke, Oddmund
(2020).
Invariant chain regulates endosomal fusion and maturation through an interaction with the SNARE Vti1b.
Journal of Cell Science.
ISSN 0021-9533.
133.
doi:
10.1242/jcs.244624.
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The Invariant chain (Ii, CD74) is a multifunctional regulator of adaptive immune responses and responsible for sorting MHC-I, MHC-II and other Ii-associated molecules to a specific endosomal pathway. When Ii is expressed, endosomal maturation and proteolytic degradation of proteins are delayed and in non-antigen presenting cells the endosomal size increase, but he molecular mechanisms are not known. We identified that a SNARE, Vti1b, is essential for regulating these Ii induced effects. Vti1b binds to Ii and Vti1b is localized at the contact sites of fusing Ii positive endosomes. Furthermore, a tailless Ii that is not internalized from the plasma membrane relocates Vti1b to the plasma membrane. KO of Ii in an antigen presenting cell line was found to speed up endosomal maturation and silencing of Vti1b inhibits the Ii induced maturation delay. Our results suggest that Ii, by interacting with the SNARE Vti1b in antigen presenting cells, direct specific Ii associated SNARE mediated fusion in the early part of the endosomal pathway that lead to a slower endosomal maturation for efficient antigen processing and MHC antigen loading.
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Hu, Xian; Jalal, Salma; Sheetz, Michael; Bakke, Oddmund & Margadant, Felix Martin
(2020).
Micro-stepping extended focus reduces photobleaching and preserves structured illumination super-resolution features.
Journal of Cell Science.
ISSN 0021-9533.
133,
p. 1–12.
doi:
10.1242/jcs.240796.
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Despite progress made in confocal microscopy, even fast systems still have insufficient temporal resolution for detailed live-cell volume imaging, such as tracking rapid movement of membrane vesicles in three-dimensional space. Depending on the shortfall, this may result in undersampling and/or motion artifacts that ultimately limit the quality of the imaging data. By sacrificing detailed information in the Z-direction, we propose a new imaging modality that involves capturing fast ‘projections’ from the field of depth and shortens imaging time by approximately an order of magnitude as compared to standard volumetric confocal imaging. With faster imaging, radiation exposure to the sample is reduced, resulting in less fluorophore photobleaching and potential photodamage. The implementation minimally requires two synchronized control signals that drive a piezo stage and trigger the camera exposure. The device generating the signals has been tested on spinning disk confocal and instant structured-illumination-microscopy (iSIM) microscopes. Our calibration images show that the approach provides highly repeatable and stable imaging conditions that enable photometric measurements of the acquired data, in both standard live imaging and super-resolution modes.
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Solbakken, Monica Hongrø; Jentoft, Sissel; Reitan, Trond; Mikkelsen, Helene; Gregers, Tone Fredsvik & Bakke, Oddmund
[Show all 8 contributors for this article]
(2019).
Disentangling the immune response and host-pathogen interactions in Francisella noatunensis infected Atlantic cod.
Comparative Biochemistry and Physiology - Part D:Genomics and Proteomics.
ISSN 1744-117X.
30,
p. 333–346.
doi:
10.1016/j.cbd.2019.04.004.
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The genetic repertoire underlying teleost immunity has been shown to be highly variable. A rare example is Atlantic cod and its relatives Gadiformes that lacks a hallmark of vertebrate immunity: Major Histocompatibility Complex class II. No immunological studies so far have fully unraveled the functionality of this particular immune system. Through global transcriptomic profiling, we investigate the immune response and host-pathogen interaction of Atlantic cod infected with the facultative intracellular bacterium <i>Francisella noatunensis</i>. We find that Atlantic cod displays an overall classic innate immune response with inflammation, acute-phase proteins and cell recruitment through up-regulation of e.g. <i>IL1B</i>, fibrinogen, cathelicidin, hepcidin and several chemotactic cytokines such as the neutrophil attractants <i>CXCL1</i> and <i>CXCL8</i>. In terms of adaptive immunity, we observe up-regulation of interferon gamma followed by up-regulation of several <i>MHCI</i> transcripts and genes related to antigen transport and loading. Finally, we find up-regulation of immunoglobulins and down-regulation of T-cell and NK-like cell markers. Our analyses also uncover some contradictory transcriptional findings such as up-regulation of anti-inflammatory <i>IL10</i> as well as down-regulation of the NADPH oxidase complex and myeloperoxidase. This we interpret as the result of host-pathogen interactions where <i>F. noatunensis</i> modulates the immune response. In summary, our results suggest that Atlantic cod mounts a classic innate immune response as well as a neutrophil-driven response. In terms of adaptive immunity, both endogenous and exogenous antigens are being presented on MHCI and antibody production is likely enabled through direct B-cell stimulation with possible neutrophil help. Collectively, we have obtained novel insight in the orchestration of the Atlantic cod immune system and determined likely targets of <i>F. noatunensis</i> host-pathogen interactions.
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Ganan, Monica; Lorentzen, Silje Benedicte; Agger, Jane Wittrup; Heyward, Catherine Anne; Bakke, Oddmund & Knutsen, Svein Halvor
[Show all 10 contributors for this article]
(2019).
Antifungal activity of well-defined chitooligosaccharide preparations against medically relevant yeasts.
PLOS ONE.
14(1).
doi:
10.1371/journal.pone.0210208.
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Due to their antifungal activity, chitosan and its derivatives have potential to be used for treating yeast infections in humans. However, to be considered for use in human medicine, it is necessary to control and know the chemical composition of the compound, which is not always the case for polymeric chitosans. Here, we analyze the antifungal activity of a soluble and well-defined chito-oligosaccharide (CHOS) with an average polymerization degree (DPn) of 32 and fraction of acetylation (FA) of 0.15 (C32) on 52 medically relevant yeast strains. Minimal inhibitory concentrations (MIC) varied widely among yeast species, strains and isolates (from > 5000 to < 9.77 μg mL-1) and inhibition patterns showed a time- and dose-dependencies. The antifungal activity was predominantly fungicidal and was inversely proportional to the pH, being maximal at pH 4.5, the lowest tested pH. Furthermore, antifungal effects of CHOS fractions with varying average molecular weight indicated that those fractions with an intermediate degree of polymerization, i.e. DP 31 and 54, had the strongest inhibitory effects. Confocal imaging showed that C32 adsorbs to the cell surface, with subsequent cell disruption and accumulation of C32 in the cytoplasm. Thus, C32 has potential to be used as a therapy for fungal infections.
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Mousavi, Seyed Ali; Skjeldal, Frode Miltzow; Fønhus, Marita Sporstøl; Haugen, Linda Hofstad; Eskild, Winnie & Berg, Trond
[Show all 7 contributors for this article]
(2019).
Receptor-mediated endocytosis of VEGF-A in rat liver sinusoidal endothelial cells.
BioMed Research International.
ISSN 2314-6133.
2019,
p. 1–12.
doi:
10.1155/2019/5496197.
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Background and Aims. Vascular endothelial growth factor (VEGF) receptors (VEGFR1 and VEGFR2) bind VEGF-A with high affinity. This study sought to determine the relative contributions of these two receptors to receptor-mediated endocytosis of VEGF-A and to clarify their endocytic itineraries in rat liver sinusoidal endothelial cells (LSECs). Methods. Isolated LSECs and radiolabeled VEGF-A were used to examine surface binding and receptor-mediated endocytosis. Quantitative real time RT-PCR (Q-RT-PCR) and Western blotting were applied to demonstrate receptor expression. Results. Q-RT-PCR analysis showed that VEGFR1 and VEGFR2 mRNA were expressed in LSECs. Ligand saturation analysis at 4°C indicated two different classes of [125I]-VEGFA binding sites on LSECs with apparent dissociation constants of 8 and 210 pM. At 37°C, LSECs efficiently took up and degraded [125I]-VEGF-A for at least 2 hours. Uptake of [125I]-VEGF-A by LSECs was blocked by dynasore that inhibits dynamin-dependent internalization, whereas inhibition of cysteine proteases by leupeptin inhibited degradation without affecting the uptake of [125I]-VEGF-A, suggesting that it is degraded following transport to lysosomes. Incubation of LSECs in the continued presence of a saturating concentration of unlabeled VEGF-A at 37°C was associated with a loss of as much as 75% of the total VEGFR2 within 30 min as shown by Western blot analysis, whereas there was no appreciable decrease in protein levels for VEGFR1 after 120 min incubation, suggesting that VEGF-A stimulation downregulates VEGFR2, but not VEGFR1, in LSECs. This possibility was supported by the observation that a hexapeptide that specifically blocks VEGF-A binding to VEGFR1 caused a marked reduction in the uptake of [125I]-VEGF-A, whereas a control peptide had no effect. Finally, live cell imaging studies using a fluorescently labeled anti-VEGFR2 antibody showed that VEGFR2 was transported via early and late endosomes to reach endolysosomes where degradation of the VEGFR2 takes place. Conclusion. Our studies suggest that, subsequent to VEGF-A binding and internalization, the unoccupied VEGFR1 may recycle to the cell surface allowing its reutilization, whereas the majority of the internalized VEGFR2 is targeted for degradation.
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Mensali, Nadia; Grenov, Charlotte Amalie; Pati, Niladri Bhusan; Dillard, Pierre; Myhre, Marit Renee & Gaudernack, Gustav
[Show all 10 contributors for this article]
(2019).
Antigen-delivery through invariant chain (CD74) boosts CD8 and CD4 T cell immunity.
Oncoimmunology.
ISSN 2162-4011.
8(3),
p. e1558663-1–e1558663-14.
doi:
10.1080/2162402X.2018.1558663.
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Eradication of tumors by the immune system relies on the efficient activation of a T-cell response. For many years, the main focus of cancer immunotherapy has been on cytotoxic CD8 T-cell. However, stimulation of CD4 helper T cells is critical for the promotion and maintenance of immune memory, thus a good vaccine should evoke a two-dimensional T-cell response. The invariant chain (Ii) is required for the MHC class II heterodimer to be correctly guided through the cell, loaded with peptide, and expressed on the surface of antigen presenting cells (APC). We previously showed that by replacing the Ii CLIP peptide by an MHC-I cancer peptide, we could efficiently load MHC-I. This prompted us to test whether longer cancer peptides could be loaded on both MHC classes and whether such peptides could be accommodated in the CLIP region of Ii. We here present data showing that expanding the CLIP replacement size leads to T-cell activation. We demonstrate by using long peptides that APCs can present peptides from the same Ii molecule on both MHC-I and -II. In addition, we present evidence that antigen presentation after Ii-loading was superior to an ER-targeted minigene construct, suggesting that ER-localization was not sufficient to obtain efficient MHC-II loading. Finally, we verified that Ii-expressing dendritic cells could prime CD4+ and CD8+ T cells from a naïve population. Taken together our study demonstrates that CLIP peptide replaced Ii constructs fulfill some of the major requirements for an efficient vector for cancer vaccination.
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Vestre, Katharina; Kjos, Ingrid; Guadagno, Noemi Antonella; Distefano, Marita Borg; Kohler, Felix & Fenaroli, Federico
[Show all 8 contributors for this article]
(2019).
Rab6 regulates cell migration and invasion by recruiting Cdc42 and modulating its activity.
Cellular and Molecular Life Sciences (CMLS).
ISSN 1420-682X.
76(13),
p. 2593–2614.
doi:
10.1007/s00018-019-03057-w.
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Rab proteins are master regulators of intracellular membrane trafficking, but they also contribute to cell division, signaling, polarization, and migration. The majority of the works describing the mechanisms used by Rab proteins to regulate cell motility involve intracellular transport of key molecules important for migration. Interestingly, a few studies indicate that Rabs can modulate the activity of Rho GTPases, important regulators for the cytoskeleton rearrangements, but the mechanisms behind this crosstalk are still poorly understood. In this work, we identify Rab6 as a negative regulator of cell migration in vitro and in vivo. We show that the loss of Rab6 promotes formation of actin protrusions and influences actomyosin dynamics by upregulating Cdc42 activity and downregulating myosin II phosphorylation. We further provide the molecular mechanism behind this regulation demonstrating that Rab6 interacts with both Cdc42 and Trio, a GEF for Cdc42. In sum, our results uncover a mechanism used by Rab proteins to ensure spatial regulation of Rho GTPase activity for coordination of cytoskeleton rearrangements required in migrating cells.
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Distefano, Marita Borg; Haugen, Linda Hofstad; Wang, Yan; Perdreau-Dahl, Harmonie; Kjos, Ingrid & Jia, Da
[Show all 10 contributors for this article]
(2018).
TBC1D5 controls the GTPase cycle of Rab7b.
Journal of Cell Science.
ISSN 0021-9533.
131(17),
p. 1–13.
doi:
10.1242/jcs.216630.
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Rab GTPases are key regulators of intracellular trafficking, and cycle between a GTP-bound active state and a GDP-bound inactive state. This cycle is regulated by guanine-nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Several efforts have been made in connecting the correct GEFs and GAPs to their specific Rab. Here, we aimed to identify GAPs for Rab7b, the small GTPase involved in transport from late endosomes to the trans-Golgi. An siRNA screen targeting proteins containing TBC domains critical for Rab GAPs was performed and coupled to a phenotypic read-out that visualized the distribution of Rab7b. Silencing of TBC1D5 provided the strongest phenotype and this protein was subsequently validated in various in vitro and cell-based assays. TBC1D5 localizes to Rab7b-positive vesicles, interacts with Rab7b and has GAP activity towards Rab7b in vitro, which is further increased by retromer proteins. Similarly to the constitutively active mutant of Rab7b, inactivation of TBC1D5 also reduces the number of CI-MPR- and sortilin-positive vesicles. Together, the results show that TBC1D5 is a GAP for Rab7b in the control of endosomal transport to the trans-Golgi.
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Haugen, Linda Hofstad; Skjeldal, Frode Miltzow; Bergeland, Trygve & Bakke, Oddmund
(2017).
Endosomal binding kinetics of Eps15 and Hrs specifically regulate the degradation of RTKs.
Scientific Reports.
7:17962,
p. 1–13.
doi:
10.1038/s41598-017-17320-2.
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Activation of EGF-R and PDGF-R triggers autophosphorylation and the recruitment of Eps15 and Hrs. These two endosomal proteins are important for specific receptor sorting. Hrs is recruiting ubiquitinated receptors to early endosomes to further facilitate degradation through the ESCRT complex. Upon receptor activation Hrs becomes phosphorylated and is relocated to the cytosol, important for receptor degradation. In this work we have studied the endosomal binding dynamics of Eps15 and Hrs upon EGF-R and PDGF-R stimulation. By analysing the fluorescence intensity on single endosomes after ligand stimulation we measured a time-specific decrease in the endosomal fluorescence level of Eps15-GFP and Hrs-YFP. Through FRAP experiments we could further register a specific change in the endosomal-membrane to cytosol binding properties of Eps15-GFP and Hrs-YFP. This specific change in membrane fractions proved to be a redistribution of the immobile fraction, which was not shown for the phosphorylation deficient mutants. We here describe a mechanism that can explain the previously observed relocation of Hrs from the endosomes to cytosol after EGF stimulation and show that Eps15 follows a similar mechanism. Moreover, this specific redistribution of the endosomal protein binding dynamics proved to be of major importance for receptor degradation.
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Margiotta, Azzurra; Progida, Cinzia; Bakke, Oddmund & Bucci, Cecilia
(2017).
Characterization of the role of RILP in cell migration.
European journal of histochemistry.
ISSN 1121-760X.
doi:
10.4081/ejh.2017.2783.
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Rab-interacting lysosomal protein (RILP) is a regulator of late stages of endocytosis. Recent work proved that depletion of RILP promotes migration of breast cancer cells in wound healing assay, whereas its overexpression influences re-arrangements of actin cytoskeleton. Here, we further characterized the role of RILP in cell migration by analyzing several aspects of this process. We showed that RILP is fundamental also for migration of lung cancer cells regulating cell velocity. RILP silencing did not affect Golgi apparatus nor microtubules reorientation during migration. However, both RILP over-expression and expression of its mutated form, RILP-C33, impair cell adhesion and spreading. In conclusion, our results demonstrate that RILP has important regulatory roles in cell motility affecting migration velocity but also in cell adhesion and cell spreading.
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Kjos, Ingrid; Distefano, Marita Borg; Sætre, Frank Ove; Repnik, Urska; Holland, Petter & Jones, Arwyn T
[Show all 10 contributors for this article]
(2017).
Rab7b modulates autophagic flux by interacting with Atg4B.
EMBO Reports.
ISSN 1469-221X.
18(10),
p. 1727–1739.
doi:
10.15252/embr.201744069.
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Autophagy (macroautophagy) is a highly conserved eukaryotic degradation pathway in which cytosolic components and organelles are sequestered by specialized autophagic membranes and degraded through the lysosomal system. The autophagic pathway maintains basal cellular homeostasis and helps cells adapt during stress; thus, defects in autophagy can cause detrimental effects. It is therefore crucial that autophagy is properly regulated. In this study, we show that the cysteine protease Atg4B, a key enzyme in autophagy that cleaves LC3, is an interactor of the small GTPase Rab7b. Indeed, Atg4B interacts and co‐localizes with Rab7b on vesicles. Depletion of Rab7b increases autophagic flux as indicated by the increased size of autophagic structures as well as the magnitude of macroautophagic sequestration and degradation. Importantly, we demonstrate that Rab7b regulates LC3 processing by modulating Atg4B activity. Taken together, our findings reveal Rab7b as a novel negative regulator of autophagy through its interaction with Atg4B.
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Margiotta, Azzurra; Progida, Cinzia; Bakke, Oddmund & Bucci, Cecilia
(2017).
Rab7a regulates cell migration through Rac1 and vimentin.
BBA - Molecular Cell Research.
ISSN 0167-4889.
1864(2),
p. 367–381.
doi:
10.1016/j.bbamcr.2016.11.020.
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Rab7a, a small GTPase of the Rab family, is localized to late endosomes and controls late endocytic trafficking. The discovery of several Rab7a interacting proteins revealed that Rab7a function is closely connected to cytoskeletal elements. Indeed, Rab7a recruits on vesicles RILP and FYCO that are responsible for the movement of Rab7a-positive vesicles and/or organelles on microtubule tracks, but also directly interacts with Rac1, a fundamental regulator of actin cytoskeleton, and with peripherin and vimentin, two intermediate filament proteins. Considering all these interactions and, in particular, the fact that Rac1 and vimentin are key factors for cellular motility, we investigated a possible role of Rab7a in cell migration. We show here that Rab7a is needed for cell migration as Rab7a depletion causes slower migration of NCI H1299 cells affecting cell velocity and directness. Rab7a depletion negatively affects adhesion and spreading onto fibronectin substrates, altering β1-integrin activation, localization and intracellular trafficking, and myosin X localization. In fact, Rab7a-depleted cells show 40% less filopodia and active integrin accumulates at the leading edge of migrating cells. Furthermore, Rab7a depletion decreases the amount of active Rac1 but not its abundance and reduces the number of cells with vimentin filaments facing the wound, indicating that Rab7a has a role in the orientation of vimentin filaments during migration. In conclusion, our results demonstrate a key role of Rab7a in the regulation of different aspects of cell migration.
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Dukic, Aleksandra; Haugen, Linda Hofstad; Pidoux, Guillaume; Leithe, Edward; Bakke, Oddmund & Tasken, Kjetil
(2017).
A protein kinase A-ezrin complex regulates connexin 43 gap junction communication in liver epithelial cells.
Cellular Signalling.
ISSN 0898-6568.
32,
p. 1–11.
doi:
10.1016/j.cellsig.2017.01.008.
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Communication between adjacent cells can occur via gap junctions (GJ) composed of connexin (Cx) hexamers that allow passage of small molecules. One of the most widely and highly expressed Cxs in human tissues is Cx43, shown to be regulated through phosphorylation by several kinases including PKA. Ezrin is a membrane associated protein that can serve as an A-kinase anchoring protein (AKAP) and hold an anchored pool of PKA. Here, we used the liver epithelial cell line IAR20, which expresses Cx43 as the predominant GJ protein, to test the hypothesis that Ezrin may associate with Cx43 in cell types that form stable GJs and serve as an AKAP. Our biochemical and proteomics data indicate that Ezrin associates with Cx43 in epithelial cells. Analyses by confocal immunofluorescence microscopy and proximity ligation assays demonstrate that Ezrin and Cx43 co-localize, together with zonula occludens-1 (ZO-1) and PKA RIα and RIIα, at the cell membrane. Quantitative gap-FRAP experiments show increased GJ intercellular communication after cAMP stimulation. Moreover, loading of cells with the Ht31 peptide that displaces both PKA RIα and RIIα from the AKAP or a peptide that disrupts the Cx43-Ezrin interaction reverts the effect and reduces the level of communication, supporting the hypothesis that in IAR20 cells Ezrin associates with Cx43 (in complex with ZO-1) which places PKA in proximity to Cx43, enabling its phosphorylation and GJ opening.
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Bauer, Johannes; Bakke, Oddmund & Morth, Jens Preben
(2016).
Overview of the membrane-associated RING-CH (MARCH) E3 ligase family.
New Biotechnology.
ISSN 1871-6784.
38,
p. 7–15.
doi:
10.1016/j.nbt.2016.12.002.
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E3 ligases are critical checkpoints for protein ubiquitination, a signal that often results in protein sorting and degradation but has also been linked to regulation of transcription and DNA repair. In line with their key role in cellular trafficking and cell-cycle control, malfunction of E3 ligases is often linked to human disease. Thus, they have emerged as prime drug targets. However, the molecular basis of action of membrane-bound E3 ligases is still unknown. Here, we review the current knowledge on the membrane-embedded MARCH E3 ligases (MARCH-1-6,7,8,11) with a focus on how the transmembrane regions can contribute via GxxxG-motifs to the selection and recognition of other membrane proteins as substrates for ubiquitination. Further understanding of the molecular parameters that govern target protein recognition of MARCH E3 ligases will contribute to development of strategies for therapeutic regulation of MARCH-induced ubiquitination.
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Øynebråten, Inger; Barois, Nicolas; Bergeland, Trygve; Kuchler, Axel Matthias; Bakke, Oddmund & Haraldsen, Guttorm
(2015).
Oligomerized, filamentous surface presentation of RANTES/CCL5 on vascular endothelial cells.
Scientific Reports.
5:9261.
doi:
10.1038/srep09261.
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Vascular endothelial cells present luminal chemokines that arrest rolling leukocytes by activating integrins. It appears that several chemokines must form higher-order oligomers to elicit proper in vivo effects, as mutants restricted to forming dimers have lost the ability to recruit leukocytes to sites of inflammation. Here, we show for the first time that the chemokine RANTES/CCL5 binds to the surface of human endothelial cells in a regular filamentous pattern. Furthermore, the filaments bound to the surface in a heparan sulfate-dependent manner. By electron microscopy we observed labeling for RANTES on membrane projections as well as on the remaining plasma membrane. Mutant constructs of RANTES restricted either in binding to heparin, or in forming dimers or tetramers, appeared either in a granular, non-filamentous pattern or were not detectable on the cell surface. The RANTES filaments were also present after exposure to flow, suggesting that they can be present in vivo. Taken together with the lacking in vivo or in vitro effects of RANTES mutants, we suggest that the filamentous structures of RANTES may be of physiological importance in leukocyte recruitment.
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Sand, Kine Marita Knudsen; Landsverk, Ole J. B.; Berg-Larsen, Axel; Bakke, Oddmund & Gregers, Tone Fredsvik
(2014).
The human-specific invariant chain isoform Iip35 modulates Iip33 trafficking and function.
Immunology and Cell Biology.
ISSN 0818-9641.
92(9),
p. 791–798.
doi:
10.1038/icb.2014.54.
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Borg, Marita Jeanett Halsen; Bakke, Oddmund & Progida, Cinzia
(2014).
A novel interaction between Rab7b and actomyosin reveals a dual role in intracellular transport and cell migration.
Journal of Cell Science.
ISSN 0021-9533.
127(22),
p. 4927–4939.
doi:
10.1242/jcs.155861.
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Berg-Larsen, Axel; Landsverk, Ole J. B.; Progida, Cinzia; Gregers, Tone Fredsvik & Bakke, Oddmund
(2013).
Differential Regulation of Rab GTPase Expression in Monocyte-Derived Dendritic Cells upon Lipopolysaccharide Activation: A Correlation to Maturation-Dependent Functional Properties.
PLOS ONE.
8(9).
doi:
10.1371/journal.pone.0073538.
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Progida, Cinzia Anita Maria; Nielsen, Morten S.; Koster, Gerbrand; Bucci, Cecilia & Bakke, Oddmund
(2012).
Dynamics of Rab7b-Dependent Transport of Sorting Receptors.
Traffic: The moving front of cell biology.
ISSN 1398-9219.
13(9),
p. 1273–1285.
doi:
10.1111/j.1600-0854.2012.01388.x.
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Skjeldal, Frode Miltzow; Strunze, Sten; Bergeland, Trygve; Walseng, Even; Gregers, Tone Fredsvik & Bakke, Oddmund
(2012).
The fusion of early endosomes induces molecular-motor-driven tubule formation and fission.
Journal of Cell Science.
ISSN 0021-9533.
125(8),
p. 1910–1919.
doi:
10.1242/jcs.092569.
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Landsverk, Ole J. B.; Ottesen, Anett Hellebø; Berg-Larsen, Axel; Appel, Silke & Bakke, Oddmund
(2012).
Differential regulation of MHC II and invariant chain expression during maturation of monocyte-derived dendritic cells.
Journal of Leukocyte Biology.
ISSN 0741-5400.
91(5),
p. 729–737.
doi:
10.1189/jlb.0311150.
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Neefjes, Jacques; Paul, Petra; Jongsma, Marlieke & Bakke, Oddmund
(2011).
Towards a systems understanding of MHC class I and MHC class II antigen presentation.
Nature reviews. Immunology.
ISSN 1474-1733.
11(12),
p. 823–836.
doi:
10.1038/nri3084.
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The molecular details of antigen processing and presentation by MHC class I and class II molecules have been studied extensively for almost three decades. Although the basic principles of these processes were laid out approximately 10 years ago, the recent years have revealed many details and provided new insights into their control and specificity. MHC molecules use various biochemical reactions to achieve successful presentation of antigenic fragments to the immune system. Here we present a timely evaluation of the biology of antigen presentation and a survey of issues that are considered unresolved. The continuing flow of new details into our understanding of the biology of MHC class I and class II antigen presentation builds a system involving several cell biological processes, which is discussed in this Review.
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Bucci, Cecilia; Bakke, Oddmund & Progida, Cinzia Anita Maria
(2011).
Rab7b and receptors trafficking.
Communicative & Integrative Biology.
3(5),
p. 401–404.
doi:
10.4161/cib.3.5.12341.
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Rab proteins are key-regulators of intracellular membrane trafficking. Rab7b is a recently identified Rab protein that may downregulate TLR4 and TLR9-mediated inflammatory responses. Rab7b, believed to have similar function as Rab7, controls however vesicular trafficking from endosomes to the TGN. It is localized to late endosomes/lysosomes as well as the TGN. Rab7b interferes with enzymes delivery to lysosomes and with the retrograde Shiga toxin transport to the Golgi. Furthermore, Rab7b depletion alters CI-MPR and TGN46 trafficking. In conclusion, Rab7b, by regulating the transport from late endosomes to the TGN, is fundamental for trafficking of several receptors, opening for a revised scenario for its influence on signaling of Toll-like Receptors (TLRs) and other receptors.
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Landsverk, Ole J. B.; Barois, Nicolas; Gregers, Tone Fredsvik & Bakke, Oddmund
(2011).
Invariant chain increases the half-life of MHC II by delaying endosomal maturation.
Immunology and Cell Biology.
ISSN 0818-9641.
89(5),
p. 619–629.
doi:
10.1038/icb.2010.143.
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Progida, Cinzia; Cogli, Laura; Piro, Francesco; Luca, Azzura De; Bakke, Oddmund & Bucci, Cecilia
(2010).
Rab7b controls trafficking from endosomes to the TGN.
Journal of Cell Science.
ISSN 0021-9533.
123(9),
p. 1480–1491.
doi:
10.1242/jcs.051474.
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Etokebe, GE; Skjeldal, F; Nilsen, Nadra; Rodionov, Dmitrii; Knezevic, Jelena & Bulat-Kardum, Ljiljana
[Show all 9 contributors for this article]
(2010).
Toll-Like Receptor 2 (P631H) Mutant Impairs Membrane Internalization and is a Dominant Negative Allele.
Scandinavian Journal of Immunology.
ISSN 0300-9475.
71(5),
p. 369–381.
doi:
10.1111/j.1365-3083.2010.02379.x.
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We have sequenced 416 Toll‐like receptor‐2 (TLR2) alleles in 208 subjects in a tuberculosis case–control study in Croatian Caucasian population. We found ten single nucleotide polymorphisms (SNP) among which three were novel (S97S, T138I and L266F). The genotype containing TLR2‐P631H SNP was significantly overrepresented in patients with tuberculosis when compared to contact controls, suggesting a small yet increased risk to disease. The causative agent of tuberculosis is Mycobacterium tuberculosis, which can bind to TLR2 with its lipoprotein coat. The TLR2‐P631H mutant has a dominant negative effect on the wild type TLR2 signalling in transfected HEK293 kidney cells using the NF‐κB‐driven luciferase as a reporter gene with ligands like M. avium extracts, Pam3CysSK4 or FSL‐1 that bind TLR2/TLR1 or TLR2/TLR6 heterodimers, respectively. Studies on internalization from the Regular Madine Darby Canine Kidney cell surface into the early endosomal compartments showed a lower rate of the mutant compared to the wild type. Our data, in combination with a report by others show that the TLR2‐P631H allele could be associated with protection to meningococcal meningitis, suggest that by dominantly inhibiting the response of cells important in the immune response this mutant might confer either protection or susceptibility to meningitis or tuberculosis, respectively.
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Låg, Marit; Rodionov, Dmitrii; Øvrevik, Johan; Bakke, Oddmund; Schwarze, Per E & Refsnes, Magne
(2010).
Cadmium-induced inflammatory responses in cells relevant for lung toxicity: Expression and release of cytokines in fibroblasts, epithelial cells and macrophages.
Toxicology Letters.
ISSN 0378-4274.
193(3),
p. 252–260.
doi:
10.1016/j.toxlet.2010.01.015.
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Bergeland, Trygve; Haugen, Linda; Landsverk, Ole J.B.; Stenmark, Harald & Bakke, Oddmund
(2008).
Cell-cycle-dependent binding kinetics for the early endosomal tethering factor EEA1.
EMBO Reports.
ISSN 1469-221X.
9(2),
p. 171–178.
doi:
10.1038/sj.embor.7401152.
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Walseng, Even; Bakke, Oddmund & Roche, Paul A.
(2008).
Major histocompatibility complex class II-peptide complexes internalize using a clathrin- and dynamin-independent endocytosis pathway.
Journal of Biological Chemistry.
ISSN 0021-9258.
283(21),
p. 14717–14727.
doi:
10.1074/jbc.M801070200.
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Bergeland, Trygve; Tewinkel, Martin & Bakke, Oddmund
(2006).
Precise calculation of photoactivation kinetics.
Nature Methods.
ISSN 1548-7091.
3(12),
p. 1048–1049.
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Measuring rapid kinetics of proteins in living cells requires the capability for fast, accurate measurements.
Researchers hoping to obtain precise kinetic data from fluorescence recovery after photobleaching or
photoactivation experiments need an easily controllable system for stimulation of a specific region and
subsequent imaging, and the Olympus FluoView FV1000 confocal laser scanning microscope (cLSM) with
SIM scanner makes this possible. We describe here how to precisely measure off rates using a cytosolic
photoactivatable probe that binds endosomal membranes.
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Gupta, Shailly N.; Kloster, Martine M.; Rodionov, Dimitrii G. & Bakke, Oddmund
(2006).
Re-routing of the invariant chain to the direct sorting pathway by introduction of an AP3-binding motif from LIMP II.
European Journal of Cell Biology.
ISSN 0171-9335.
85(6),
p. 457–467.
doi:
10.1016/j.ejcb.2006.02.001.
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Bergeland, Trygve; Tewinkel, Martin & Bakke, Oddmund
(2006).
Precise calculation of photoactivation kinetics.
Nature Methods.
ISSN 1548-7091.
3(12),
p. 1048–1049.
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Note i artikkelen i tidsskriftet: This article was submitted to Nature Methods by a commercial organization
and has not been peer reviewed. Nature Methods takes no responsibility for
the accuracy or otherwise of the information provided. Skal ikke rapporteres./tøf
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Øynebråten, Inger; Barois, Nicolas; Hagelsteen, Kathrine; Johansen, Finn Eirik; Bakke, Oddmund & Haraldsen, Guttorm
(2005).
Characterization of a novel chemokine-containing storage granule in endothelial cells: evidence for preferential exocytosis mediated by protein kinase A and diacylglycerol.
Journal of Immunology.
ISSN 0022-1767.
175(8),
p. 5358–5369.
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We have recently shown that several proinflammatory chemokines can be stored in secretory granules of endothelial cells (ECs). Subsequent regulated exocytosis of such chemokines may then enable rapid recruitment of leukocytes to inflammatory sites. Although IL-8/CXCL8 and eotaxin-3/CCL26 are sorted to the rod-shaped Weibel-Palade body (WPB), we found that GROalpha/CXCL1 and MCP-1/CCL2 reside in small granules that, similarly to the WPB, respond to secretagogue stimuli. In the present study, we report that GROalpha and MCP-1 colocalized in 50- to 100-nm granules, which occur throughout the cytoplasm and at the cell cortex. Immunofluorescence confocal microscopy revealed no colocalization with multimerin or tissue plasminogen activator, i.e., proteins that are released from small granules of ECs by regulated exocytosis. Moreover, the GROalpha/MCP-1-containing granules were Rab27-negative, contrasting the Rab27-positive, WPB. The secretagogues PMA, histamine, and forskolin triggered distinct dose and time-dependent responses of GROalpha release. Furthermore, GROalpha release was more sensitive than IL-8 release to inhibitors and activators of PKA and PKC but not to an activator of Epac, a cAMP-regulated GTPase exchange factor, indicating that GROalpha release is regulated by molecular adaptors different from those regulating exocytosis of the WPB. On the basis of these findings, we designated the GROalpha/MCP-1-containing compartment the type 2 granule of regulated secretion in ECs, considering the WPB the type 1 compartment. In conclusion, we propose that the GROalpha/MCP-1-containing type 2 granule shows preferential responsiveness to important mediators of EC activation, pointing to the existence of selective agonists that would allow differential release of selected chemokines.
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Øynebråten, Inger; Barois, Nicolas; Hagelsteen, Kathrine; Johansen, Finn Eirik; Bakke, Oddmund & Haraldsen, Guttorm
(2005).
Characterization of a novel chemokine-containing storage granule in endothelial cells: evidence for preferential exocytosis mediated by protein kinase A and diacylglycerol.
Journal of Immunology.
ISSN 0022-1767.
175(8),
p. 5358–5369.
Full text in Research Archive
Show summary
We have recently shown that several proinflammatory chemokines can be stored in secretory granules of endothelial cells (ECs). Subsequent regulated exocytosis of such chemokines may then enable rapid recruitment of leukocytes to inflammatory sites. Although IL-8/CXCL8 and eotaxin-3/CCL26 are sorted to the rod-shaped Weibel-Palade body (WPB), we found that GROalpha/CXCL1 and MCP-1/CCL2 reside in small granules that, similarly to the WPB, respond to secretagogue stimuli. In the present study, we report that GROalpha and MCP-1 colocalized in 50- to 100-nm granules, which occur throughout the cytoplasm and at the cell cortex. Immunofluorescence confocal microscopy revealed no colocalization with multimerin or tissue plasminogen activator, i.e., proteins that are released from small granules of ECs by regulated exocytosis. Moreover, the GROalpha/MCP-1-containing granules were Rab27-negative, contrasting the Rab27-positive, WPB. The secretagogues PMA, histamine, and forskolin triggered distinct dose and time-dependent responses of GROalpha release. Furthermore, GROalpha release was more sensitive than IL-8 release to inhibitors and activators of PKA and PKC but not to an activator of Epac, a cAMP-regulated GTPase exchange factor, indicating that GROalpha release is regulated by molecular adaptors different from those regulating exocytosis of the WPB. On the basis of these findings, we designated the GROalpha/MCP-1-containing compartment the type 2 granule of regulated secretion in ECs, considering the WPB the type 1 compartment. In conclusion, we propose that the GROalpha/MCP-1-containing type 2 granule shows preferential responsiveness to important mediators of EC activation, pointing to the existence of selective agonists that would allow differential release of selected chemokines.
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Barois, Nicolas & Bakke, Oddmund
(2005).
AP-4 as a component of the clathrin coat machinery: A morphological study.
Biochemical Journal.
ISSN 0264-6021.
385(2),
p. 503–510.
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The four members of the adaptor protein family are heterotetrameric cytosolic complexes involved in the intracellular trafficking of cargo proteins between different organelles. They interact with motifs present in the cytoplasmic tail of their specific cargo proteins at different intracellular locations. While AP-1, AP-2 and AP-3 have been investigated extensively, very few studies have focused on fourth member, AP-4. In the present study, we report on the intracellular localisation of AP-4 in MDCK and MelJuSo cell lines after immunogold labelling of ultrathin cryosections. We find that AP-4 is localised mainly in the Golgi complex, as well as on endosomes and transport vesicles. Interestingly, and for the first time, we show that AP-4 is localised with the clathrin coat machinery in the Golgi complex and in the endocytic pathway. Furthermore, we find that AP-4 is localised with CI-MPR, but not with TfR, LAMP-2 or Ii. The difference in morphology between CI-MPR/AP-4 positive vesicles and CI-MPR/AP-1 positive vesicles raises the possibility that AP-4 acts at a place different from that of AP-1 in the intracellular trafficking pathway of CI-MPR.
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Barois, Nicolas & Bakke, Oddmund
(2005).
AP-4 as a component of the clathrin coat machinery: A morphological study.
Biochemical Journal.
ISSN 0264-6021.
385(2),
p. 503–510.
Full text in Research Archive
Show summary
The four members of the adaptor protein family are heterotetrameric cytosolic complexes involved in the intracellular trafficking of cargo proteins between different organelles. They interact with motifs present in the cytoplasmic tail of their specific cargo proteins at different intracellular locations. While AP-1, AP-2 and AP-3 have been investigated extensively, very few studies have focused on fourth member, AP-4. In the present study, we report on the intracellular localisation of AP-4 in MDCK and MelJuSo cell lines after immunogold labelling of ultrathin cryosections. We find that AP-4 is localised mainly in the Golgi complex, as well as on endosomes and transport vesicles. Interestingly, and for the first time, we show that AP-4 is localised with the clathrin coat machinery in the Golgi complex and in the endocytic pathway. Furthermore, we find that AP-4 is localised with CI-MPR, but not with TfR, LAMP-2 or Ii. The difference in morphology between CI-MPR/AP-4 positive vesicles and CI-MPR/AP-1 positive vesicles raises the possibility that AP-4 acts at a place different from that of AP-1 in the intracellular trafficking pathway of CI-MPR.
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Lawton, Anna P.; Prigozy, TI; Brossay, L; Pei, B; Khurana, Archana & Martin, David M. A.
[Show all 13 contributors for this article]
(2005).
The mouse CD1d cytoplasmic tail mediates CD1d trafficking and antigen presentation by adaptor protein 3-dependent and -independent mechanisms.
Journal of Immunology.
ISSN 0022-1767.
174(6),
p. 3179–3186.
Full text in Research Archive
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Dahle, Øyvind; Bakke, Oddmund & Gabrielsen, Odd Stokke
(2004).
c-Myb associates with PML in nuclear bodies in hematopoietic cells.
Experimental Cell Research.
ISSN 0014-4827.
297(1),
p. 118–126.
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The c-Myb transcription factor plays a central role in the regulation of cell growth and differentiation of hematopoietic cells. Being the product of a proto-oncogene, one would expect c-Myb function to be modulated by signal transduction pathways, but our knowledge on such regulation of c-Myb is rather limited. Recently, we and others showed that c-Myb is subjected to sumoylation and that this posttranslational modification has considerable effect on c-Myb's activity. Interestingly, many proteins subjected to SUMO-1 conjugation associate with the promyelocytic leukemia (PML) protein and localize to PML nuclear bodies (PML NBs). Although the precise molecular function of PML NBs still remains to be defined, they seem to play a role in regulation of gene expression and are linked to specific cellular signaling. We show here that c-Myb localizes to PML NBs and that c-Myb interacts with PML as judged by immunofluorescence microcopy and co-immunoprecipitation experiments. Enforced expression of PML IV was shown to enhance c-Myb-dependent reporter activation. Our results imply a role for PML and possibly other components of PML NBs in regulating c-Myb's activity. This novel link between c-Myb and PML, two gene products being implicated in leukemic disorders, suggests that previously unknown mechanisms for regulating c-Myb's activity involving PML may exist.
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Dahle, Øyvind; Bakke, Oddmund & Gabrielsen, Odd Stokke
(2004).
c-Myb associates with PML in nuclear bodies in hematopoietic cells.
Experimental Cell Research.
ISSN 0014-4827.
297,
p. 118–126.
Full text in Research Archive
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Øynebråten, Inger; Oynebraten, Inger; Bakke, Oddmund; Brandtzæg, Per; Johansen, Finn Erik & Haraldsen, Guttorm
(2004).
Rapid chemokine secretion from endothelial cells originates from 2 distinct compartments.
Blood.
ISSN 0006-4971.
104(2),
p. 314–320.
Full text in Research Archive
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The neutrophil-attracting chemokine interleukin 8 (IL-8) is stored in the Weibel-Palade body (WPB) of endothelial cells (ECs) from which it can be rapidly released after exposure to the secretagogues histamine or thrombin. In this manner, IL-8 may enable rapid recruitment of leukocytes to inflammatory sites. To explore the possible storage of EC-derived chemokines that may attract other subsets of leukocytes, we examined the intracellular localization and secretagogue responsiveness of growth-related oncogene alpha (GROalpha), monocyte chemoattractant protein-1 (MCP-1), eotaxin-3, interferon-gamma-inducible protein 10 (IP-10), and regulated on activation, normal T-cell expressed and secreted (RANTES). While eotaxin-3, GROalpha, and MCP-1 were rapidly released from ECs, the release of the T-cell attractors RANTES and IP-10 was not sensitive to the secretagogues. Moreover, of the 3 former chemokines, only eotaxin-3 was stored in WPBs. GROalpha and MCP-1 resided mainly in smaller vesicles compatible with sorting to a different, histamine-responsive compartment, which has been described in ECs although not reported to contain chemokines. In conclusion, we propose that rapid release of chemokines is restricted to those primarily recruiting leukocytes of the innate immune system, and that their storage in ECs is not restricted to the WPB compartment.
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Gregers, Tone; Nordeng, Tommy W.; Birkeland, Hanne; Sandlie, Inger & Bakke, Oddmund
(2003).
The cytoplasmic tail of invariant chain modulates antigen processing and presentation.
European Journal of Immunology.
ISSN 0014-2980.
198(8),
p. 1133–1146.
Full text in Research Archive
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The MHC class II-associated invariant chain (Ii) has several important functions in antigen presentation. In this study, we have examined the effect of Iip33 expression on endocytic transport and antigen presentation. We find that degradation of both endocytosed antigen and Ii itself is delayed in cells expressing high levels of Ii, whereas a mutant Ii with an altered charge distribution in the cytoplasmic tail was unable to exert this effect. Furthermore, the Ii mutant did not enhance the presentation of an Ii-dependent MHC class II-restricted epitope to the same extent as the wild type. In a parallel study, we investigated the effect of charge in the cytoplasmic tail of Ii. We find that due to exposed negative charges, it promotes endosome fusion events, and we suggest that this causes endosomal retention (Nordeng et al., Mol. Biol. Cell 2002). Together, the data reveal an additional property of the Iip33 cytoplasmic tail that contributes to the modulation of antigen processing and presentation.
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Barrett, Jeannie & Bakke, Oddmund
(2003).
Firing up B cells.
http://www.the-elso-gazette.org/.
Full text in Research Archive
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B cells have to gear-up their secretory protein production before they can devote themselves to producing the antibodies that fight infections. A new proteomics study documents the endoplasmic reticulum protein reinforcements that are recruited to this task.
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Elewaut, Dirk; Lawton, Anna P.; Nagarajan, Niranjana A.; Maverakis, Emanual; Khurana, Archana & Höning, Stefan
[Show all 10 contributors for this article]
(2003).
The Adaptor Protein AP-3 Is Required for CD1d-Mediated Antigen Presentation of Glycosphingolipids and Development of V14i NKT Cells.
Journal of Experimental Medicine (JEM).
ISSN 0022-1007.
198(8),
p. 1133–1146.
Full text in Research Archive
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Relatively little is known about the pathway leading to the presentation of glycolipids by CD1 molecules. Here we show that the adaptor protein complex 3 (AP-3) is required for the efficient presentation of glycolipid antigens that require internalization and processing. AP-3 interacts with mouse CD1d, and cells from mice deficient for AP-3 have increased cell surface levels of CD1d and decreased expression in late endosomes. Spleen cells from AP-3-deficient mice have a reduced ability to present glycolipids to natural killer T (NKT) cells. Furthermore, AP-3-deficient mice have a significantly reduced NKT cell population, although this is not caused by self-tolerance that might result from increased CD1d surface levels. These data suggest that the generation of the endogenous ligand that selects NKT cells may also be AP-3 dependent. However, the function of MHC class II-reactive CD4+ T lymphocytes is not altered by AP-3 deficiency. Consistent with this divergence from the class II pathway, NKT cell development and antigen presentation by CD1d are not reduced by invariant chain deficiency. These data demonstrate that the AP-3 requirement is a particular attribute of the CD1d pathway in mice and that, although MHC class II molecules and CD1d are both found in late endosomes or lysosomes, different pathways mediate their intracellular trafficking.
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Bakke, Oddmund; Fleckenstein, Burkhard; Gregers, Tone F.; Roepstorff, Peter; Sandlie, Inger & Vartdal, Frode
(2003).
MHC class II loading of high or low affinity peptides directed by Ii/peptide fusion constructs:implications for T cell activation.
International Immunology.
ISSN 0953-8178.
15(11),
p. 1291–1299.
Full text in Research Archive
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Bakke, Oddmund & Barrett, Jeannie
(2003).
Firing up B cells.
ELSO Gazette.
2(15).
Full text in Research Archive
Show summary
B cells have to gear-up their secretory protein
production before they can devote themselves
to producing the antibodies that fight
infections. A new proteomics study documents
the endoplasmic reticulum protein
reinforcements that are recruited to this task.
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Gregers, Tone F.; Nordeng, Tommy W. & Bakke, Oddmund
(2003).
Antigen Presentation by MHC Class II Molecules.
In Gorvel, Jean-Pierre (Eds.),
Intracellular Pathogens in Membrane Interactions and Vacuole Biogenesis.
Eurekah.com and Kluwer Academic / Plenum Publishers..
ISSN 9780306478338.
p. 251–278.
Full text in Research Archive
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Gregers, Tone F.; Nordeng, Tommy W.; Birkeland, Hanne C. G.; Sandlie, Inger & Bakke, Oddmund
(2003).
THE CYTOPLASMIC TAIL OF INVARIANT CHAIN MODULATES ANTIGEN PROCESSING AND PRESENTATION.
European Journal of Immunology.
ISSN 0014-2980.
33(2),
p. 277–286.
Full text in Research Archive
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Bakke, Oddmund; Elewaut, D; Lawton, AP; Nagarajan, NA; Maverakis, E & Khurana, A
[Show all 11 contributors for this article]
(2003).
The adaptor protein AP-3 is required for CD1d-mediated antigen presentation of glycosphingolipids and development of Valpha14i NKT cells.
Journal of Experimental Medicine (JEM).
ISSN 0022-1007.
198(8),
p. 1133–1146.
Full text in Research Archive
View all works in NVA
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Hu, Xian; Margadant, Felix & Bakke, Oddmund
(2026).
Micro-stepping extended focus reduces photobleaching and preserves structured illumination super-resolution features.
Show summary
Despite the progress made in fast scan units, confocal systems still have insufficient temporal resolution for many
volume imaging requirements, such as tracking movement of membrane vesicles in live cells. Researchers might
sacrifice certain imaging modalities to achieve better performance in temporal resolution. This may result in imaging
artifacts such as undersampling artifacts and limit the amount of analyzable data.
We propose a imaging modality producing fast projections from the field of depth which will shorten the imaging time
by approximately an order of magnitude compared to volume imaging. The implementation requires merely a
minimum two synchronized control signals that drive a piezo stage and trigger the camera exposure, a third, optional
signal, blanks the laser output when the stage is in motion which mildly improves the stability and repeatability of the
exposure. The device generating the signals has been tested on spinning disk confocal as well as on instant structured-
illumination-microscopy (iSIM) microscopes. Our calibration images show that the approach provides highly repeatable
and stable imaging conditions and does enable photometric measurements of the acquired data, in both the regular
spinning disk setup as well as in the iSIM configuration.While light sheet microscopes can provide even faster
projections of the same volume, the presented method provides more homogeneous optical sectioning and maintains
the structured illumination characteristics.
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Perdreau, Harmonie; Guldsten, Hanne; Progida, Cinzia; Thiede, Bernd; Bakke, Oddmund & Morth, Jens Preben
(2014).
Molecular and Structural Characterization of Sjögren syndrome/scleroderma autoantigen 1 (SSSCA1).
Full text in Research Archive
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Müller, Elisabeth; Stavna, A.; Jahnsen, Frode Lars; Bakke, Oddmund & Corthay, Alexandre
(2013).
Using Live Imaging to Investigate the Mechanisms Underlying Tumor Cell Killing by Macrophages.
Scandinavian Journal of Immunology.
ISSN 0300-9475.
77(4),
p. 275–276.
Full text in Research Archive
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Landsverk, Ole J. B.; Gregers, Tone Fredsvik & Bakke, Oddmund
(2012).
Differential regulation of MHC II and invariant chain expression during maturation of monocyte derived dendritic cells and how invariant chain increases the half-life of MHC II by delaying endosomal maturation.
Molecular Immunology.
ISSN 0161-5890.
51(1),
p. 7–7.
doi:
10.1016/j.molimm.2012.02.012.
Full text in Research Archive
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Bakke, Oddmund & Andersson, K. Kristoffer
(2012).
Åpent seminar: Fra imaging show til celler og proteinsrukturer.
NBS-nytt.
ISSN 0801-3535.
1,
p. 22–22.
Full text in Research Archive
Show summary
Fra imaging show til celler og proteinstrukturer
Oddmund Bakke og K. Kristoffer Andersson, IMBV, Univ. Oslo.
I anledning universitetets 200 års jubileum og Mat Nat Fakultetets 150 års jubileum i 2011 vi i oppdrag å fylle en dag med cellebiologi/strukturbiologi og lage en kortfilm med moderne mikroskopi som tema. Den 12. oktober ble et slikt møte arrangert i det høyteknologiske auditoriet i det nye IT bygget, Ole-Johan Dahls hus. Første del av programmet spente fra undervisning i cellebiologi til autofagi og det nyeste innen mikroskopi. Ikke minst var det stor spenning knyttet til premieren på kortfilmen ”Evolution”.
http://www.mn.uio.no/imbv/english/about/news-and-events/events/imbvday/index.html
From Imaging Show to Cells
Join the Imaging Show and listen to international top scientists explain our understanding of the structure of the smallest living unit in the body: The cell. On October 12 2011, Department of Molecular Biosciences arranges the IMBV Day.
Time and place: Oct 12, 2011 09:00 AM - 04:15 PM, Auditorium Simula, Ole-Johan Dahls hus
Image
Our understanding of life has advanced tremendously during the last 20 years. Today we can determine the structure of molecules, alone and in complex with other molecules, and we can build detailed models of the functions of cells. Aided by advanced microscopy and data technology we can even make movies inside living cells, directly observing single molecules and cell constituents.
On this day, leading local and international experts in cell biology and protein crystallography will explain cellular molecules and structures and our current understanding of living organisms. Through sound and pictures we will experience a 3D and 4D imaging show of cells, filmed using microscopic laser technology.
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Wälchli, Sebastien; Landsverk, Ole J. B.; Fallang, Lars-Egil; Olweus, Johanna; Bakke, Oddmund & Gregers, Tone Fredsvik
(2012).
Invariant chain as a tool to load antigenic peptides on MHC class I.
Molecular Immunology.
ISSN 0161-5890.
51(1),
p. 16–16.
doi:
10.1016/j.molimm.2012.02.039.
Full text in Research Archive
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Sand, Kine Marita Knudsen; Landsverk, Ole J. B.; Bakke, Oddmund & Gregers, Tone Fredsvik
(2012).
Intracellular trafficking of the human invariant chain isoforms, Iip33 and Iip35.
Molecular Immunology.
ISSN 0161-5890.
51(1),
p. 30–30.
doi:
10.1016/j.molimm.2012.02.081.
Full text in Research Archive
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Kucera, Ana; Bakke, Oddmund & Gregers, Tone Fredsvik
(2011).
Direct Targeting of Invariant Chain to the MHC II Loading Compartment.
Scandinavian Journal of Immunology.
ISSN 0300-9475.
73(4),
p. 362–362.
Full text in Research Archive
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Sundvold-Gjerstad, Vibeke; Kristiansen, Tone Fredsvik; Granum, Stine; Berge, Tone; Koster, Gerbrand & Skjeldal, Frode Miltzow
[Show all 9 contributors for this article]
(2011).
T cell Specific Adapter Protein (TSAd) Relocates the Tec Family Protein Tyrosine Kinase Itk from the Plasma Membrane to the Perinuclear Area.
Scandinavian Journal of Immunology.
ISSN 0300-9475.
73(4),
p. 359–359.
Full text in Research Archive
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Kucera, Ana; Bakke, Oddmund & Gregers, Tone Fredsvik
(2011).
The Role of Inhibitory NKR-P1 Receptors in the Gut.
Scandinavian Journal of Immunology.
ISSN 0300-9475.
73(4),
p. 362–363.
Full text in Research Archive
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Sand, Kine Marita Knudsen; Bakke, Oddmund & Gregers, Tone Fredsvik
(2011).
The Role of li p35 in MHC Class II Antigen Presentation.
Scandinavian Journal of Immunology.
ISSN 0300-9475.
73(4),
p. 358–358.
Full text in Research Archive
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Berg-Larsen, Axel; Landsverk, Ole J. B.; Gregers, Tone Fredsvik & Bakke, Oddmund
(2011).
Rab GTPases are Differentially Regulated Duringe DC Maturation.
Scandinavian Journal of Immunology.
ISSN 0300-9475.
73(4),
p. 361–361.
Full text in Research Archive
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Hol, Johanna; Wik, Jonas Aakre; Poulsen, Lars La Cour & Bakke, Oddmund
(2016).
Glucose and Vascular Inflammation. Thesis for the degree of Master of Science in Molecular Biosciences, University of Oslo.
Universitetet i Oslo.
Full text in Research Archive
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Published
Nov. 4, 2010 2:35 PM
- Last modified
Feb. 20, 2024 10:01 PM
