1
|
Moreno-Corona NC, de León-Bautista MP, León-Juárez M, Hernández-Flores A, Barragán-Gálvez JC, López-Ortega O. Rab GTPases, Active Members in Antigen-Presenting Cells, and T Lymphocytes. Traffic 2024; 25:e12950. [PMID: 38923715 DOI: 10.1111/tra.12950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 04/25/2024] [Accepted: 05/27/2024] [Indexed: 06/28/2024]
Abstract
Processes such as cell migration, phagocytosis, endocytosis, and exocytosis refer to the intense exchange of information between the internal and external environment in the cells, known as vesicular trafficking. In eukaryotic cells, these essential cellular crosstalks are controlled by Rab GTPases proteins through diverse adaptor proteins like SNAREs complex, coat proteins, phospholipids, kinases, phosphatases, molecular motors, actin, or tubulin cytoskeleton, among others, all necessary for appropriate mobilization of vesicles and distribution of molecules. Considering these molecular events, Rab GTPases are critical components in specific biological processes of immune cells, and many reports refer primarily to macrophages; therefore, in this review, we address specific functions in immune cells, concretely in the mechanism by which the GTPase contributes in dendritic cells (DCs) and, T/B lymphocytes.
Collapse
Affiliation(s)
| | - Mercedes Piedad de León-Bautista
- Escuela de Medicina, Universidad Vasco de Quiroga, Morelia, Mexico
- Human Health, Laboratorio de Enfermedades Infecciosas y Genómica (INEX LAB), Morelia, Mexico
| | - Moises León-Juárez
- Laboratorio de Virología Perinatal y Diseño Molecular de Antígenos y Biomarcadores, Departamento de Inmunobioquimica, Instituto Nacional de Perinatología, Ciudad de México, Mexico
| | | | - Juan Carlos Barragán-Gálvez
- División de Ciencias Naturales y Exactas, Departamento de Farmacia, Universidad de Guanajuato, Guanajuato, Mexico
| | - Orestes López-Ortega
- Université Paris Cité, INSERM UMR-S1151, CNRS UMR-S8253, Institute Necker Enfants Malades, Paris, France
| |
Collapse
|
2
|
The Succinate Receptor SUCNR1 Resides at the Endoplasmic Reticulum and Relocates to the Plasma Membrane in Hypoxic Conditions. Cells 2022; 11:cells11142185. [PMID: 35883628 PMCID: PMC9321536 DOI: 10.3390/cells11142185] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/08/2022] [Accepted: 07/09/2022] [Indexed: 12/24/2022] Open
Abstract
The GPCR SUCNR1/GPR91 exerts proangiogenesis upon stimulation with the Krebs cycle metabolite succinate. GPCR signaling depends on the surrounding environment and intracellular localization through location bias. Here, we show by microscopy and by cell fractionation that in neurons, SUCNR1 resides at the endoplasmic reticulum (ER), while being fully functional, as shown by calcium release and the induction of the expression of the proangiogenic gene for VEGFA. ER localization was found to depend upon N-glycosylation, particularly at position N8; the nonglycosylated mutant receptor localizes at the plasma membrane shuttled by RAB11. This SUCNR1 glycosylation is physiologically regulated, so that during hypoxic conditions, SUCNR1 is deglycosylated and relocates to the plasma membrane. Downstream signal transduction of SUCNR1 was found to activate the prostaglandin synthesis pathway through direct interaction with COX-2 at the ER; pharmacologic antagonism of the PGE2 EP4 receptor (localized at the nucleus) was found to prevent VEGFA expression. Concordantly, restoring the expression of SUCNR1 in the retina of SUCNR1-null mice renormalized vascularization; this effect is markedly diminished after transfection of the plasma membrane-localized SUCNR1 N8A mutant, emphasizing that ER localization of the succinate receptor is necessary for proper vascularization. These findings uncover an unprecedented physiologic process where GPCR resides at the ER for signaling function.
Collapse
|
3
|
Kumari S, Dash PK, Kumari T, Guo ML, Ghosh JK, Buch SJ, Tripathi RK. HIV-1 Nef hijacks both exocytic and endocytic pathways of host intracellular trafficking through differential regulation of Rab GTPases. Biol Cell 2022; 114:276-292. [PMID: 35713972 DOI: 10.1111/boc.202100027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 12/01/2022]
Abstract
HIV-1 Nef regulates several cellular functions in an infected cell which results in viral persistence and AIDS pathogenesis. The currently understood molecular mechanism(s) underlying Nef-dependent cellular function(s) are unable to explain how events are coordinately regulated in the host cell. Intracellular membranous trafficking maintains cellular homeostasis and is regulated by Rab GTPases - a member of the Ras superfamily. In the current study, we tried to decipher the role of Nef on the Rab GTPases-dependent complex and vesicular trafficking. Expression profiling of Rabs in Nef-expressing cells showed that Nef differentially regulates the expression of individual Rabs in a cell-specific manner. Further analysis of Rabs in HIV-1NL4-3 or ΔNef infected cells demonstrated that the Nef protein is responsible for variation in Rabs expression. Using a panel of competitive peptide inhibitors against Nef, we identified the critical domain of HIV-1 Nef involved in modulation of Rabs expression. The molecular function of Nef-mediated upregulation of Rab5 and Rab7 and downregulation of Rab11 increased the transport of SERINC5 from the cell surface to the lysosomal compartment. Moreover, the Nef-dependent increase in Rab27 expression assists exosome release. Reversal of Rabs expression using competitive inhibitors against Nef and manipulation of Rabs expression reduced viral release and infectivity of progeny virions. Overall, this study demonstrates that Nef differentially regulates the expression of Rab proteins in HIV-1 infected cells to hijack the host intracellular trafficking, which augments viral replication and HIV-1 pathogenesis. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Sushila Kumari
- Virus Research and Therapeutics Division, CSIR-Central Drug Research Institute, Sector-10, Janakipuram Extension, Sitapur Road, Lucknow, U.P., 226031, India
| | - Prasanta K Dash
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Tripti Kumari
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector-10, Janakipuram Extension, Sitapur Road, Lucknow, U.P., 226031, India
| | - Ming-Lei Guo
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Jimut Kanti Ghosh
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector-10, Janakipuram Extension, Sitapur Road, Lucknow, U.P., 226031, India
| | - Shilpa J Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Raj Kamal Tripathi
- Virus Research and Therapeutics Division, CSIR-Central Drug Research Institute, Sector-10, Janakipuram Extension, Sitapur Road, Lucknow, U.P., 226031, India
| |
Collapse
|
4
|
Vestre K, Persiconi I, Borg Distefano M, Mensali N, Guadagno NA, Bretou M, Wälchli S, Arnold-Schrauf C, Bakke O, Dalod M, Lennon-Dumenil AM, Progida C. Rab7b regulates dendritic cell migration by linking lysosomes to the actomyosin cytoskeleton. J Cell Sci 2021; 134:272095. [PMID: 34494097 PMCID: PMC8487646 DOI: 10.1242/jcs.259221] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 08/16/2021] [Indexed: 12/26/2022] Open
Abstract
Lysosomal signaling facilitates the migration of immune cells by releasing Ca2+ 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 trans-Golgi network (TGN). Here, we show that Rab7b regulates the migration of dendritic cells (DCs) in one- and three-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 the 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 Ca2+ channel TRPML1 (also known as MCOLN1), enabling the local activation of myosin II at the cell rear. Taken together, our findings identify Rab7b as the missing physical link between lysosomes and the actomyosin cytoskeleton, allowing control of immune cell migration through lysosomal signaling. This article has an associated First Person interview with the first author of the paper. Summary: The small GTPase Rab7b bridges the lysosomal Ca2+ channel TRPML1 to myosin II, thus enabling the local activation of myosin II at the cell rear and promoting fast migration of dendritic cells.
Collapse
Affiliation(s)
- Katharina Vestre
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, 0316 Oslo, Norway
| | - Irene Persiconi
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, 0316 Oslo, Norway
| | - Marita Borg Distefano
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, 0316 Oslo, Norway
| | - Nadia Mensali
- Department of Cellular Therapy, the Radium Hospital, Oslo University Hospital, 0379 Oslo, Norway
| | | | - Marine Bretou
- Institut Curie, Inserm U932, F-75005 Paris, France.,VIB-KU Leuven Center for Brain and Disease Research, 3000 Leuven, Belgium
| | - Sébastien Wälchli
- Department of Cellular Therapy, the Radium Hospital, Oslo University Hospital, 0379 Oslo, Norway
| | - Catharina Arnold-Schrauf
- Aix Marseille Univ, CNRS, INSERM, Centre d'Immunologie de Marseille-Luminy, 13288 Marseille, France
| | - Oddmund Bakke
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, 0316 Oslo, Norway
| | - Marc Dalod
- Aix Marseille Univ, CNRS, INSERM, Centre d'Immunologie de Marseille-Luminy, 13288 Marseille, France
| | | | - Cinzia Progida
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, 0316 Oslo, Norway
| |
Collapse
|
5
|
Expression and localisation of Rab44 in immune-related cells change during cell differentiation and stimulation. Sci Rep 2020; 10:10728. [PMID: 32612275 PMCID: PMC7329882 DOI: 10.1038/s41598-020-67638-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 06/12/2020] [Indexed: 12/18/2022] Open
Abstract
Rab44 is a large Rab GTPase that contains a Rab-GTPase domain and some additional domains, such as EF-hand and coiled-coil domains at the N-terminus. Our previous study showed that Rab44 negatively regulates osteoclast differentiation by modulating intracellular calcium levels; however, aside from those findings, there is little information concerning Rab44 on other cells or tissues. In this study, we showed that Rab44 was highly expressed in bone marrow cells among various mouse tissues. Immunohistochemical studies indicated that Rab44 was detectable by only a small number of cells in the immune-related tissues and that Rab44 was partially detected in CD117-positive cells, but not in Stem cell antigen 1-positive cells in the bone marrow. Rab44 expression levels were decreased during differentiation of immune-related cells, such as neutrophils, macrophages, and dendritic cells compared with bone marrow cells. Although endogenous Rab44 in macrophages was localised in lysosomes, lipopolysaccharide (LPS) stimulation led to partial translocation to early endosomes and the plasma membrane. Moreover, Rab44 expression levels were altered by treatment with various immunomodulators, including LPS. These results indicate that Rab44 expression and localisation in bone marrow cells and macrophages alters with cell differentiation and stimulation.
Collapse
|
6
|
Budzik JM, Swaney DL, Jimenez-Morales D, Johnson JR, Garelis NE, Repasy T, Roberts AW, Popov LM, Parry TJ, Pratt D, Ideker T, Krogan NJ, Cox JS. Dynamic post-translational modification profiling of Mycobacterium tuberculosis-infected primary macrophages. eLife 2020; 9:51461. [PMID: 31951200 PMCID: PMC7030789 DOI: 10.7554/elife.51461] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 01/16/2020] [Indexed: 12/23/2022] Open
Abstract
Macrophages are highly plastic cells with critical roles in immunity, cancer, and tissue homeostasis, but how these distinct cellular fates are triggered by environmental cues is poorly understood. To uncover how primary murine macrophages respond to bacterial pathogens, we globally assessed changes in post-translational modifications of proteins during infection with Mycobacterium tuberculosis, a notorious intracellular pathogen. We identified hundreds of dynamically regulated phosphorylation and ubiquitylation sites, indicating that dramatic remodeling of multiple host pathways, both expected and unexpected, occurred during infection. Most of these cellular changes were not captured by mRNA profiling, and included activation of ubiquitin-mediated autophagy, an evolutionarily ancient cellular antimicrobial system. This analysis also revealed that a particular autophagy receptor, TAX1BP1, mediates clearance of ubiquitylated Mtb and targets bacteria to LC3-positive phagophores. These studies provide a new resource for understanding how macrophages shape their proteome to meet the challenge of infection.
Collapse
Affiliation(s)
- Jonathan M Budzik
- Department of Medicine, University of California, San Francisco, San Francisco, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Danielle L Swaney
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, United States.,Gladstone Institutes, San Francisco, United States
| | - David Jimenez-Morales
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, United States.,Gladstone Institutes, San Francisco, United States.,Department of Medicine, Division of Cardiovascular Medicine, Stanford University, Stanford, United States
| | - Jeffrey R Johnson
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, United States.,Gladstone Institutes, San Francisco, United States
| | - Nicholas E Garelis
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Teresa Repasy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Allison W Roberts
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Lauren M Popov
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Trevor J Parry
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| | - Dexter Pratt
- Department of Medicine, University of California, San Diego, La Jolla, United States
| | - Trey Ideker
- Department of Medicine, University of California, San Diego, La Jolla, United States
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, United States.,Gladstone Institutes, San Francisco, United States
| | - Jeffery S Cox
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States
| |
Collapse
|
7
|
Progida C, Bakke O. Bidirectional traffic between the Golgi and the endosomes - machineries and regulation. J Cell Sci 2016; 129:3971-3982. [PMID: 27802132 DOI: 10.1242/jcs.185702] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The bidirectional transport between the Golgi complex and the endocytic pathway has to be finely regulated in order to ensure the proper delivery of newly synthetized lysosomal enzymes and the return of sorting receptors from degradative compartments. The high complexity of these routes has led to experimental difficulties in properly dissecting and separating the different pathways. As a consequence, several models have been proposed during the past decades. However, recent advances in our understanding of endosomal dynamics have helped to unify these different views. We provide here an overview of the current insights into the transport routes between Golgi and endosomes in mammalian cells. The focus of the Commentary is on the key molecules involved in the trafficking pathways between these intracellular compartments, such as Rab proteins and sorting receptors, and their regulation. A proper understanding of the bidirectional traffic between the Golgi complex and the endolysosomal system is of uttermost importance, as several studies have demonstrated that mutations in the factors involved in these transport pathways result in various pathologies, in particular lysosome-associated diseases and diverse neurological disorders, such as Alzheimer's and Parkinson's disease.
Collapse
Affiliation(s)
- Cinzia Progida
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Oddmund Bakke
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Oslo, Norway
| |
Collapse
|
8
|
Kang L, Hao X, Tang Y, Wei X, Gong Y. RABEX-5 overexpression in gastric cancer is correlated with elevated MMP-9 level. Am J Transl Res 2016; 8:2365-2374. [PMID: 27347344 PMCID: PMC4891449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 02/23/2016] [Indexed: 06/06/2023]
Abstract
OBJECTIVE This study aimed to investigate mRNA and protein expression levels of RABEX-5 and matrix metalloproteinase-9 (MMP-9), their mutual correlation, and biological behavior in gastric cancer (GC) patients. METHODS The expression levels of RABEX-5 and MMP-9 were determined by real-time quantitative PCR and Western blotting in cell lines, GC tissues, and adjacent normal tissues. In addition, RABEX-5 and MMP-9 expression was analyzed by immunohistochemistry in formalin-fixed tissues from 113 GC patients. RESULTS The mRNA and protein expression levels of RABEX-5 and MMP-9 in GC cell lines and GC tissues were higher than those in normal gastric mucosa cell line and adjacent normal tissues. RABEX-5 expression and MMP-9 expression in GC tissues were significantly and positively correlated. In addition, the size of tumor (p<0.001), Lauren's classification (p=0.009), and N stage (p<0.001) were identified as the relative factors of RABEX-5 expression, whereas the expression of MMP-9 was correlated with N stage (p=0.003). The results of the multivariate analysis revealed that the independent predictive factors of overall survival were T stage (hazard ratio (HR)=2.382; p=0.028), N stage (HR=1.755; p<0.001), RABEX-5 expression (HR=0.452; p=0.004), and MMP-9 expression (HR=0.561; p=0.032). CONCLUSIONS RABEX-5 and MMP-9 expression levels were elevated in GC tissues and were associated with tumor invasion, metastasis, and prognosis. Therefore, they may be promising prognostic indicators of survival in GC patients.
Collapse
Affiliation(s)
- Lili Kang
- Department of Gastroenterology, Tianjin Hospital of ITCWM, Nankai Hospital Sanwei Road, Nankai District, Tianjin 300100, China
| | - Xuwen Hao
- Department of Gastroenterology, Tianjin Hospital of ITCWM, Nankai Hospital Sanwei Road, Nankai District, Tianjin 300100, China
| | - Yanping Tang
- Department of Gastroenterology, Tianjin Hospital of ITCWM, Nankai Hospital Sanwei Road, Nankai District, Tianjin 300100, China
| | - Xiaodong Wei
- Department of Gastroenterology, Tianjin Hospital of ITCWM, Nankai Hospital Sanwei Road, Nankai District, Tianjin 300100, China
| | - Yanxia Gong
- Department of Gastroenterology, Tianjin Hospital of ITCWM, Nankai Hospital Sanwei Road, Nankai District, Tianjin 300100, China
| |
Collapse
|
9
|
Kucera A, Borg Distefano M, Berg-Larsen A, Skjeldal F, Repnik U, Bakke O, Progida C. Spatiotemporal Resolution of Rab9 and CI-MPR Dynamics in the Endocytic Pathway. Traffic 2016; 17:211-29. [PMID: 26663757 DOI: 10.1111/tra.12357] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 12/08/2015] [Accepted: 12/08/2015] [Indexed: 12/21/2022]
Abstract
Rab9 is a small GTPase that localizes to the trans-Golgi Network (TGN) and late endosomes. Its main function has long been connected to the recycling of mannose-6-phosphate receptors (MPRs). However, recent studies link Rab9 also to autophagy and lysosome biogenesis. In this paper, using confocal imaging, we characterize for the first time the live dynamics of the Rab9 constitutively active mutant, Rab9Q66L. We find that it localizes predominantly to late endosomes and that its expression in HeLa cells disperses TGN46 and cation-independent (CI-MPR) away from the Golgi yet, has no effect on the retrograde transport of CI-MPR. We also show that CI-MPR and Rab9 enter the endosomal pathway together at the transition stage between early, Rab5-positive, and late, Rab7a-positive, endosomes. CI-MPR localizes transiently to separate domains on these endosomes, where vesicles carrying CI-MPR attach and detach within seconds. Taken together, our results demonstrate that Rab9 mediates the delivery of CI-MPR to the endosomal pathway, entering the maturing endosome at the early-to-late transition.
Collapse
Affiliation(s)
- Ana Kucera
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Marita Borg Distefano
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Axel Berg-Larsen
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Oslo, Norway.,Current address: Department of Cancer Immunology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Frode Skjeldal
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Urska Repnik
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Oddmund Bakke
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Oslo, Norway
| | - Cinzia Progida
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Oslo, Norway
| |
Collapse
|
10
|
Distefano MB, Kjos I, Bakke O, Progida C. Rab7b at the intersection of intracellular trafficking and cell migration. Commun Integr Biol 2015; 8:e1023492. [PMID: 27066171 PMCID: PMC4802807 DOI: 10.1080/19420889.2015.1023492] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 02/21/2015] [Indexed: 02/06/2023] Open
Abstract
Rab proteins are small GTPases essential for controlling and coordinating intracellular traffic. The small GTPase Rab7b regulates the retrograde transport from late endosomes toward the Trans-Golgi Network (TGN), and is important for the proper trafficking of several receptors such as Toll-like receptors (TLRs) and sorting receptors. We recently identified the actin motor protein myosin II as a new interaction partner for Rab7b, and found that Rab7b transport is dependent on myosin II. Interestingly, we also discovered that Rab7b influences the phosphorylation state of myosin II by controlling the activation status of the small GTPase RhoA. Consequently, Rab7b is important for the remodeling of actin filaments in processes such as stress fiber formation, cell adhesion, polarization and cell migration. Our finding that Rab7b can control actomyosin reorganization reveals yet another important role for Rab proteins, in addition to their already established role as master regulators of intracellular transport. Here we discuss our findings and speculate how they can explain the importance of Rab7b in dendritic cells (DCs).
Collapse
Affiliation(s)
- Marita Borg Distefano
- Department of Biosciences; Center for Immune Regulation; University of Oslo ; Oslo, Norway
| | - Ingrid Kjos
- Department of Biosciences; Center for Immune Regulation; University of Oslo ; Oslo, Norway
| | - Oddmund Bakke
- Department of Biosciences; Center for Immune Regulation; University of Oslo ; Oslo, Norway
| | - Cinzia Progida
- Department of Biosciences; Center for Immune Regulation; University of Oslo ; Oslo, Norway
| |
Collapse
|
11
|
Borg M, Bakke O, Progida C. A novel interaction between Rab7b and actomyosin reveals a dual role in intracellular transport and cell migration. J Cell Sci 2014; 127:4927-39. [PMID: 25217632 DOI: 10.1242/jcs.155861] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Rab proteins are small GTPases that regulate transport between the different compartments of the endomembrane system in eukaryotic cells. Here, we show that Rab7b, a Rab that controls the transport between late endosomes and the trans Golgi network, interacts directly with myosin II. We illustrate the functional relevance of this interaction, demonstrating that myosin II mediates the transport of Rab7b endosomes, as Rab7b dynamics are strongly affected after myosin II depletion or inhibition. We also demonstrate that a member of the Rab family regulates actin remodeling and, consequently, influences cell adhesion, polarization and migration. We find the molecular mechanism by which Rab7b influences stress fiber formation - through controlling the activation status of the small GTPase RhoA and therefore influencing myosin light chain phosphorylation. Our findings reveal a newly identified role for Rab proteins outside of their canonical role in intracellular trafficking, identifying Rab7b as a coordinator of cytoskeletal organization.
Collapse
Affiliation(s)
- Marita Borg
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Blindernveien 31, 0371 Oslo, Norway
| | - Oddmund Bakke
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Blindernveien 31, 0371 Oslo, Norway
| | - Cinzia Progida
- Department of Biosciences, Centre for Immune Regulation, University of Oslo, Blindernveien 31, 0371 Oslo, Norway
| |
Collapse
|