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Erol ÖD, Şenocak Ş, Aerts-Kaya F. The Role of Rab GTPases in the development of genetic and malignant diseases. Mol Cell Biochem 2024; 479:255-281. [PMID: 37060515 DOI: 10.1007/s11010-023-04727-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/01/2023] [Indexed: 04/16/2023]
Abstract
Small GTPases have been shown to play an important role in several cellular functions, including cytoskeletal remodeling, cell polarity, intracellular trafficking, cell-cycle, progression and lipid transformation. The Ras-associated binding (Rab) family of GTPases constitutes the largest family of GTPases and consists of almost 70 known members of small GTPases in humans, which are known to play an important role in the regulation of intracellular membrane trafficking, membrane identity, vesicle budding, uncoating, motility and fusion of membranes. Mutations in Rab genes can cause a wide range of inherited genetic diseases, ranging from neurodegenerative diseases, such as Parkinson's disease (PD) and Alzheimer's disease (AD) to immune dysregulation/deficiency syndromes, like Griscelli Syndrome Type II (GS-II) and hemophagocytic lymphohistiocytosis (HLH), as well as a variety of cancers. Here, we provide an extended overview of human Rabs, discussing their function and diseases related to Rabs and Rab effectors, as well as focusing on effects of (aberrant) Rab expression. We aim to underline their importance in health and the development of genetic and malignant diseases by assessing their role in cellular structure, regulation, function and biology and discuss the possible use of stem cell gene therapy, as well as targeting of Rabs in order to treat malignancies, but also to monitor recurrence of cancer and metastasis through the use of Rabs as biomarkers. Future research should shed further light on the roles of Rabs in the development of multifactorial diseases, such as diabetes and assess Rabs as a possible treatment target.
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Affiliation(s)
- Özgür Doğuş Erol
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey
| | - Şimal Şenocak
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey
| | - Fatima Aerts-Kaya
- Department of Stem Cell Sciences, Hacettepe University Graduate School of Health Sciences, 06100, Ankara, Turkey.
- Hacettepe University Center for Stem Cell Research and Development, 06100, Ankara, Turkey.
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2
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Deng L, Solichin MR, Adyaksa DNM, Septianastiti MA, Fitri RA, Suwardan GNR, Matsui C, Abe T, Shoji I. Cellular Release of Infectious Hepatitis C Virus Particles via Endosomal Pathways. Viruses 2023; 15:2430. [PMID: 38140670 PMCID: PMC10747773 DOI: 10.3390/v15122430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
Hepatitis C virus (HCV) is a positive-sense, single-stranded RNA virus that causes chronic hepatitis, liver cirrhosis and hepatocellular carcinoma. The release of infectious HCV particles from infected hepatocytes is a crucial step in viral dissemination and disease progression. While the exact mechanisms of HCV particle release remain poorly understood, emerging evidence suggests that HCV utilizes intracellular membrane trafficking and secretory pathways. These pathways include the Golgi secretory pathway and the endosomal trafficking pathways, such as the recycling endosome pathway and the endosomal sorting complex required for transport (ESCRT)-dependent multivesicular bodies (MVBs) pathway. This review provides an overview of recent advances in understanding the release of infectious HCV particles, with a particular focus on the involvement of the host cell factors that participate in HCV particle release. By summarizing the current knowledge in this area, this review aims to contribute to a better understanding of endosomal pathways involved in the extracellular release of HCV particles and the development of novel antiviral strategies.
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Affiliation(s)
- Lin Deng
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (L.D.); (D.N.M.A.); (M.A.S.); (T.A.)
| | - Muchamad Ridotu Solichin
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (L.D.); (D.N.M.A.); (M.A.S.); (T.A.)
- Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Dewa Nyoman Murti Adyaksa
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (L.D.); (D.N.M.A.); (M.A.S.); (T.A.)
- Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Maria Alethea Septianastiti
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (L.D.); (D.N.M.A.); (M.A.S.); (T.A.)
- Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Rhamadianti Aulia Fitri
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (L.D.); (D.N.M.A.); (M.A.S.); (T.A.)
- Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta 55281, Indonesia
| | - Gede Ngurah Rsi Suwardan
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (L.D.); (D.N.M.A.); (M.A.S.); (T.A.)
- Department of Clinical Microbiology, Faculty of Medicine, Universitas Udayana, Bali 80361, Indonesia
| | - Chieko Matsui
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (L.D.); (D.N.M.A.); (M.A.S.); (T.A.)
| | - Takayuki Abe
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (L.D.); (D.N.M.A.); (M.A.S.); (T.A.)
| | - Ikuo Shoji
- Division of Infectious Disease Control, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan; (L.D.); (D.N.M.A.); (M.A.S.); (T.A.)
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3
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Xue M, Xiao J, Jiang W, Wang Y, Zuo D, An H, Ren L. Loss of BCAA catabolism enhances Rab1A-mTORC1 signaling activity and promotes tumor proliferation in NSCLC. Transl Oncol 2023; 34:101696. [PMID: 37216755 DOI: 10.1016/j.tranon.2023.101696] [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: 02/03/2023] [Revised: 04/10/2023] [Accepted: 05/12/2023] [Indexed: 05/24/2023] Open
Abstract
BACKGROUND Non-small cell lung cancer (NSCLC) is a leading cause of cancer death. Branched-chain amino acid (BCAA) homeostasis is important for normal physiological metabolism. Branched-chain keto acid dehydrogenase kinase (BCKDK) is a rate-limiting enzyme involved in BCAA degradation. BCAA metabolism has been highlighted in human cancers. The aberrant activation of mTORC1 has been implicated in tumor progression. Rab1A is a small GTPase, an activator of mTORC1, and an oncogene. This study aimed to reveal the specific role of BCKDK-BCAA-Rab1A-mTORC1 signaling in NSCLC. METHODS We analyzed a cohort of 79 patients with NSCLC and 79 healthy controls. Plasma BCAA assays, immunohistochemistry, and network and pathway analyses were performed. The stable cell lines BCKDK-KD, BCKDK-OV A549, and H1299 were constructed. BCKDK, Rab1A, p-S6 and S6 were detected using western blotting to explore their molecular mechanisms of action in NSCLC. The effects of BCAA and BCKDK on the apoptosis and proliferation of H1299 cells were detected by cell function assays. RESULTS We demonstrated that NSCLC was primarily involved in BCAA degradation. Therefore, combining BCAA, CEA, and Cyfra21-1 is clinically useful for treating NSCLC. We observed a significant increase in BCAA levels, downregulation of BCKDHA expression, and upregulation of BCKDK expression in NSCLC cells. BCKDK promotes proliferation and inhibits apoptosis in NSCLC cells, and we observed that BCKDK affected Rab1A and p-S6 in A549 and H1299 cells via BCAA modulation. Leucine affected Rab1A and p-S6 in A549 and H1299 cells and affected the apoptosis rate of H1299 cells. In conclusion, BCKDK enhances Rab1A-mTORC1 signaling and promotes tumor proliferation by suppressing BCAA catabolism in NSCLC, suggesting a new biomarker for the early diagnosis and identification of metabolism-based targeted approaches for patients with NSCLC.
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Affiliation(s)
- Meiting Xue
- Department of Clinical Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Jiawei Xiao
- Department of Clinical Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Wenna Jiang
- Department of Clinical Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Yanhui Wang
- Department of Clinical Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Duo Zuo
- Department of Clinical Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Haohua An
- Department of Clinical Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China
| | - Li Ren
- Department of Clinical Laboratory, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Tianjin's Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin 300060, China.
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Evidence for the role of Rab11-positive recycling endosomes as intermediates in coronavirus egress from epithelial cells. Histochem Cell Biol 2022; 158:241-251. [PMID: 35604431 PMCID: PMC9124743 DOI: 10.1007/s00418-022-02115-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2022] [Indexed: 12/19/2022]
Abstract
AbstractAfter their assembly by budding into the lumen of the intermediate compartment (IC) at the endoplasmic reticulum (ER)–Golgi interface, coronaviruses (CoVs) are released from their host cells following a pathway that remains poorly understood. The traditional view that CoV exit occurs via the constitutive secretory route has recently been questioned by studies suggesting that this process involves unconventional secretion. Here, using the avian infectious bronchitis virus (IBV) as a well-established model virus, we have applied confocal microscopy to investigate the pathway of CoV egress from epithelial Vero cells. We report a novel effect of IBV infection on cellular endomembranes, namely, the compaction of the pericentrosomal endocytic recycling compartment (ERC) defined by the GTPase Rab11, which coincides with the previously described Golgi fragmentation, as well as virus release. Despite Golgi disassembly, the IC elements containing the major IBV membrane protein (M)—which mostly associates with newly formed virus particles—maintain their close spatial connection with the Rab11-positive endocytic recycling system. Moreover, partial colocalization of the M protein with Rab11 was observed, whereas M displayed negligible overlap with LAMP-1, indicating that IBV egress does not occur via late endosomes or lysosomes. Synchronization of virus release using temperature-shift protocols was accompanied by increased colocalization of M and Rab11 in vesicular and vacuolar structures in the pericentrosomal region and at the cell periphery, most likely representing IBV-containing transport carriers. In conclusion, these results add CoVs to the growing list of viruses exploiting the endocytic recycling apparatus defined by Rab11 for their assembly and/or release.
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Jordan KL, Koss DJ, Outeiro TF, Giorgini F. Therapeutic Targeting of Rab GTPases: Relevance for Alzheimer's Disease. Biomedicines 2022; 10:1141. [PMID: 35625878 PMCID: PMC9138223 DOI: 10.3390/biomedicines10051141] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/22/2022] [Accepted: 04/18/2022] [Indexed: 11/16/2022] Open
Abstract
Rab GTPases (Rabs) are small proteins that play crucial roles in vesicle transport and membrane trafficking. Owing to their widespread functions in several steps of vesicle trafficking, Rabs have been implicated in the pathogenesis of several disorders, including cancer, diabetes, and multiple neurodegenerative diseases. As treatments for neurodegenerative conditions are currently rather limited, the identification and validation of novel therapeutic targets, such as Rabs, is of great importance. This review summarises proof-of-concept studies, demonstrating that modulation of Rab GTPases in the context of Alzheimer's disease (AD) can ameliorate disease-related phenotypes, and provides an overview of the current state of the art for the pharmacological targeting of Rabs. Finally, we also discuss the barriers and challenges of therapeutically targeting these small proteins in humans, especially in the context of AD.
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Affiliation(s)
- Kate L. Jordan
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester LE1 7RH, UK;
| | - David J. Koss
- Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; (D.J.K.); (T.F.O.)
| | - Tiago F. Outeiro
- Faculty of Medical Sciences, Translational and Clinical Research Institute, Newcastle University, Newcastle Upon Tyne NE2 4HH, UK; (D.J.K.); (T.F.O.)
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, 37075 Göttingen, Germany
- Max Planck Institute for Natural Sciences, 37075 Göttingen, Germany
- Scientific Employee with a Honorary Contract at Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), 37075 Göttingen, Germany
| | - Flaviano Giorgini
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester LE1 7RH, UK;
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de Los Ángeles Juricic Urzúa M, Gallardo Rojas J, Couve Correa A, Cerda M, Härtel Gründler S, González-Silva C. The Dendritic Ergic: Microtubule And Actin Cytoskeletons Participate In Stop-And-Go Movement Of Mobile Carriers Between Stable Structures. Traffic 2022; 23:174-187. [PMID: 35075729 DOI: 10.1111/tra.12832] [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: 04/15/2021] [Revised: 12/30/2021] [Accepted: 01/20/2022] [Indexed: 11/29/2022]
Abstract
The ER-to-Golgi intermediate compartment (ERGIC) is a membranous organelle that mediates protein transport between the endoplasmic reticulum (ER) and the Golgi apparatus. In neurons, clusters of these vesiculotubular structures are situated throughout the cell in proximity to the ER, passing cargo to the cis-Golgi cisternae, located mainly in the perinuclear region. Although ERGIC markers have been identified in neurons, the distribution and dynamics of neuronal ERGIC structures have not been characterized yet. Here, we show that long-distance ERGIC transport occurs via an intermittent mechanism in dendrites, with mobile elements moving between stationary structures. Slow and fast live-cell imaging have captured stable ERGIC structures remaining in place over long periods of time, as well as mobile ERGIC structures advancing very short distances along dendrites. These short distances have been consistent with the lengths between the stationary ERGIC structures. Kymography revealed ERGIC elements that moved intermittently, emerging from and fusing with stationary ERGIC structures. Interestingly, this movement apparently depends not only on the integrity of the microtubule cytoskeleton, as previously reported, but on the actin cytoskeleton as well. Our results indicate that the dendritic ERGIC has a dual nature, with both stationary and mobile structures. The neural ERGIC network transports proteins via a stop-and-go movement in which both the microtubule and the actin cytoskeletons participate. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- María de Los Ángeles Juricic Urzúa
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute (BNI), Santiago, Chile
| | - Javiera Gallardo Rojas
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute (BNI), Santiago, Chile
| | - Andrés Couve Correa
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute (BNI), Santiago, Chile
| | - Mauricio Cerda
- Biomedical Neuroscience Institute (BNI), Santiago, Chile.,Integrative Biology Program, Institute of Biomedical Sciences (ICBM), Center for Medical Informatics and Telemedicine (CIMT), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Steffen Härtel Gründler
- Biomedical Neuroscience Institute (BNI), Santiago, Chile.,Integrative Biology Program, Institute of Biomedical Sciences (ICBM), Center for Medical Informatics and Telemedicine (CIMT), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Carolina González-Silva
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute (BNI), Santiago, Chile
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7
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Hirata Y, Matsui Y, Wada I, Hosokawa N. ER-to-Golgi trafficking of procollagen III via conventional vesicular and tubular carriers. Mol Biol Cell 2022; 33:ar21. [PMID: 35044867 PMCID: PMC9250382 DOI: 10.1091/mbc.e21-07-0372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Collagen is the major protein component of the extracellular matrix. Synthesis of procollagens starts in the endoplasmic reticulum (ER), and three ⍺ chains form a rigid triple helix 300-400 nm in length. It remains unclear how such a large cargo is transported from the ER to the Golgi apparatus. In this study, to elucidate the intracellular transport of fibril-forming collagens, we fused cysteine-free GFP to the N-telopeptide region of procollagen III (GFP-COL3A1) and analyzed transport by live-cell imaging. We found that the maturation dynamics of procollagen III were largely different from those of network-forming procollagen IV (Matsui et al. 2020). Proline hydroxylation of procollagen III uniquely triggered the formation of intralumenal droplet-like structures similar to events caused by liquid-liquid phase separation, and ER exit sites surrounded large droplets containing chaperones. Procollagen III was transported to the Golgi apparatus via vesicular and tubular carriers containing ERGIC53 and RAB1B; this process required TANGO1 and CUL3, which we previously reported were dispensable for procollagen IV. GFP-COL3A1 and mCherry-⍺1AT were co-transported in the same vesicle. Based on these findings, we propose that shortly after ER exit, enlarged carriers containing procollagen III fuse to ERGIC for transport to the Golgi apparatus by conventional cargo carriers. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text].
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Affiliation(s)
- Yukihiro Hirata
- Laboratory of Molecular and Cellular Biology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Yuto Matsui
- Laboratory of Molecular and Cellular Biology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Ikuo Wada
- Department of Cell Science, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine, Fukushima 960-1295, Japan
| | - Nobuko Hosokawa
- Laboratory of Molecular and Cellular Biology, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
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8
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Branched Actin Maintains Acetylated Microtubule Network in the Early Secretory Pathway. Cells 2021; 11:cells11010015. [PMID: 35011578 PMCID: PMC8750537 DOI: 10.3390/cells11010015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 12/12/2021] [Accepted: 12/17/2021] [Indexed: 11/17/2022] Open
Abstract
In the early secretory pathway, the delivery of anterograde cargoes from the endoplasmic reticulum (ER) exit sites (ERES) to the Golgi apparatus is a multi-step transport process occurring via the ER-Golgi intermediate compartment (IC, also called ERGIC). While the role microtubules in ER-to-Golgi transport has been well established, how the actin cytoskeleton contributes to this process remains poorly understood. Here, we report that Arp2/3 inhibition affects the network of acetylated microtubules around the Golgi and induces the accumulation of unusually long RAB1/GM130-positive carriers around the centrosome. These long carriers are less prone to reach the Golgi apparatus, and arrival of anterograde cargoes to the Golgi is decreased upon Arp2/3 inhibition. Our data suggest that Arp2/3-dependent actin polymerization maintains a stable network of acetylated microtubules, which ensures efficient cargo trafficking at the late stage of ER to Golgi transport.
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9
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Christensen JR, Kendrick AA, Truong JB, Aguilar-Maldonado A, Adani V, Dzieciatkowska M, Reck-Peterson SL. Cytoplasmic dynein-1 cargo diversity is mediated by the combinatorial assembly of FTS-Hook-FHIP complexes. eLife 2021; 10:74538. [PMID: 34882091 PMCID: PMC8730729 DOI: 10.7554/elife.74538] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 12/08/2021] [Indexed: 11/13/2022] Open
Abstract
In eukaryotic cells, intracellular components are organized by the microtubule motors cytoplasmic dynein-1 (dynein) and kinesins, which are linked to cargos via adaptor proteins. While ~40 kinesins transport cargo toward the plus end of microtubules, a single dynein moves cargo in the opposite direction. How dynein transports a wide variety of cargos remains an open question. The FTS–Hook–FHIP (‘FHF’) cargo adaptor complex links dynein to cargo in humans and fungi. As human cells have three Hooks and four FHIP proteins, we hypothesized that the combinatorial assembly of different Hook and FHIP proteins could underlie dynein cargo diversity. Using proteomic approaches, we determine the protein ‘interactome’ of each FHIP protein. Live-cell imaging and biochemical approaches show that different FHF complexes associate with distinct motile cargos. These complexes also move with dynein and its cofactor dynactin in single-molecule in vitro reconstitution assays. Complexes composed of FTS, FHIP1B, and Hook1/Hook3 colocalize with Rab5-tagged early endosomes via a direct interaction between FHIP1B and GTP-bound Rab5. In contrast, complexes composed of FTS, FHIP2A, and Hook2 colocalize with Rab1A-tagged ER-to-Golgi cargos and FHIP2A is involved in the motility of Rab1A tubules. Our findings suggest that combinatorial assembly of different FTS–Hook–FHIP complexes is one mechanism dynein uses to achieve cargo specificity.
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Affiliation(s)
- Jenna R Christensen
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States
| | - Agnieszka A Kendrick
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States
| | - Joey B Truong
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States
| | | | - Vinit Adani
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States
| | - Monika Dzieciatkowska
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver, Aurora, United States
| | - Samara L Reck-Peterson
- Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, United States
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10
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Focus on the Small GTPase Rab1: A Key Player in the Pathogenesis of Parkinson's Disease. Int J Mol Sci 2021; 22:ijms222112087. [PMID: 34769517 PMCID: PMC8584362 DOI: 10.3390/ijms222112087] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/04/2021] [Accepted: 11/06/2021] [Indexed: 12/19/2022] Open
Abstract
Parkinson’s disease (PD) is the second most frequent neurodegenerative disease. It is characterized by the loss of dopaminergic neurons in the substantia nigra and the formation of large aggregates in the survival neurons called Lewy bodies, which mainly contain α-synuclein (α-syn). The cause of cell death is not known but could be due to mitochondrial dysfunction, protein homeostasis failure, and alterations in the secretory/endolysosomal/autophagic pathways. Survival nigral neurons overexpress the small GTPase Rab1. This protein is considered a housekeeping Rab that is necessary to support the secretory pathway, the maintenance of the Golgi complex structure, and the regulation of macroautophagy from yeast to humans. It is also involved in signaling, carcinogenesis, and infection for some pathogens. It has been shown that it is directly linked to the pathogenesis of PD and other neurodegenerative diseases. It has a protective effect against α–σψν toxicity and has recently been shown to be a substrate of LRRK2, which is the most common cause of familial PD and the risk of sporadic disease. In this review, we analyze the key aspects of Rab1 function in dopamine neurons and its implications in PD neurodegeneration/restauration. The results of the current and former research support the notion that this GTPase is a good candidate for therapeutic strategies.
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11
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Martinez-Arroyo O, Selma-Soriano E, Ortega A, Cortes R, Redon J. Small Rab GTPases in Intracellular Vesicle Trafficking: The Case of Rab3A/Raphillin-3A Complex in the Kidney. Int J Mol Sci 2021; 22:7679. [PMID: 34299299 PMCID: PMC8303874 DOI: 10.3390/ijms22147679] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 12/12/2022] Open
Abstract
Small Rab GTPases, the largest group of small monomeric GTPases, regulate vesicle trafficking in cells, which are integral to many cellular processes. Their role in neurological diseases, such as cancer and inflammation have been extensively studied, but their implication in kidney disease has not been researched in depth. Rab3a and its effector Rabphillin-3A (Rph3A) expression have been demonstrated to be present in the podocytes of normal kidneys of mice rats and humans, around vesicles contained in the foot processes, and they are overexpressed in diseases with proteinuria. In addition, the Rab3A knockout mice model induced profound cytoskeletal changes in podocytes of high glucose fed animals. Likewise, RphA interference in the Drosophila model produced structural and functional damage in nephrocytes with reduction in filtration capacities and nephrocyte number. Changes in the structure of cardiac fiber in the same RphA-interference model, open the question if Rab3A dysfunction would produce simultaneous damage in the heart and kidney cells, an attractive field that will require attention in the future.
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Affiliation(s)
- Olga Martinez-Arroyo
- Cardiometabolic and Renal Risk Research Group, INCLIVA Biomedical Research Institute, 46010 Valencia, Spain; (O.M.-A.); (R.C.)
| | - Estela Selma-Soriano
- Physiopathology of Cellular and Organic Oxidative Stress Group, University of Valencia, 46100 Valencia, Spain;
| | - Ana Ortega
- Cardiometabolic and Renal Risk Research Group, INCLIVA Biomedical Research Institute, 46010 Valencia, Spain; (O.M.-A.); (R.C.)
| | - Raquel Cortes
- Cardiometabolic and Renal Risk Research Group, INCLIVA Biomedical Research Institute, 46010 Valencia, Spain; (O.M.-A.); (R.C.)
| | - Josep Redon
- Cardiometabolic and Renal Risk Research Group, INCLIVA Biomedical Research Institute, 46010 Valencia, Spain; (O.M.-A.); (R.C.)
- CIBERObn, Carlos III Institute, 28029 Madrid, Spain
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12
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Embarc-Buh A, Francisco-Velilla R, Martinez-Salas E. RNA-Binding Proteins at the Host-Pathogen Interface Targeting Viral Regulatory Elements. Viruses 2021; 13:952. [PMID: 34064059 PMCID: PMC8224014 DOI: 10.3390/v13060952] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/10/2021] [Accepted: 05/17/2021] [Indexed: 12/16/2022] Open
Abstract
Viral RNAs contain the information needed to synthesize their own proteins, to replicate, and to spread to susceptible cells. However, due to their reduced coding capacity RNA viruses rely on host cells to complete their multiplication cycle. This is largely achieved by the concerted action of regulatory structural elements on viral RNAs and a subset of host proteins, whose dedicated function across all stages of the infection steps is critical to complete the viral cycle. Importantly, not only the RNA sequence but also the RNA architecture imposed by the presence of specific structural domains mediates the interaction with host RNA-binding proteins (RBPs), ultimately affecting virus multiplication and spreading. In marked difference with other biological systems, the genome of positive strand RNA viruses is also the mRNA. Here we focus on distinct types of positive strand RNA viruses that differ in the regulatory elements used to promote translation of the viral RNA, as well as in the mechanisms used to evade the series of events connected to antiviral response, including translation shutoff induced in infected cells, assembly of stress granules, and trafficking stress.
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Affiliation(s)
| | | | - Encarnacion Martinez-Salas
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Nicolás Cabrera 1, 28049 Madrid, Spain; (A.E.-B.); (R.F.-V.)
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13
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Zhang X, Wang X, Yuan Z, Radford SJ, Liu C, Libutti SK, Zheng XFS. Amino acids-Rab1A-mTORC1 signaling controls whole-body glucose homeostasis. Cell Rep 2021; 34:108830. [PMID: 33730578 PMCID: PMC8062038 DOI: 10.1016/j.celrep.2021.108830] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 12/28/2020] [Accepted: 02/16/2021] [Indexed: 12/17/2022] Open
Abstract
Rab1A is a small GTPase known for its role in vesicular trafficking. Recent evidence indicates that Rab1A is essential for amino acids (aas) sensing and signaling to regulate mTORC1 in normal and cancer cells. However, Rab1A's in vivo function in mammals is not known. Here, we report the generation of tamoxifen (TAM)-induced whole body Rab1A knockout (Rab1A-/-) in adult mice. Rab1A-/- mice are viable but become hyperglycemic and glucose intolerant due to impaired insulin transcription and β-cell proliferation and maintenance. Mechanistically, Rab1A mediates AA-mTORC1 signaling, particularly branched chain amino acids (BCAA), to regulate the stability and localization of the insulin transcription factor Pdx1. Collectively, these results reveal a physiological role of aa-Rab1A-mTORC1 signaling in the control of whole-body glucose homeostasis in mammals. Intriguingly, Rab1A expression is reduced in β-cells of type 2 diabetes (T2D) patients, which is correlated with loss of insulin expression, suggesting that Rab1A downregulation contributes to T2D progression.
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Affiliation(s)
- Xin Zhang
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA; Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, the State University of New Jersey, 675 Hoes Lane, Piscataway, NJ 08854, USA
| | - Xiaowen Wang
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA; Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, the State University of New Jersey, 675 Hoes Lane, Piscataway, NJ 08854, USA
| | - Ziqiang Yuan
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA; Department of Surgery, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA
| | - Sarah J Radford
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA
| | - Chen Liu
- Department of Pathology and Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA
| | - Steven K Libutti
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA; Department of Surgery, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA
| | - X F Steven Zheng
- Rutgers Cancer Institute of New Jersey, Rutgers, The State University of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA; Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, the State University of New Jersey, 675 Hoes Lane, Piscataway, NJ 08854, USA.
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14
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Tremel S, Ohashi Y, Morado DR, Bertram J, Perisic O, Brandt LTL, von Wrisberg MK, Chen ZA, Maslen SL, Kovtun O, Skehel M, Rappsilber J, Lang K, Munro S, Briggs JAG, Williams RL. Structural basis for VPS34 kinase activation by Rab1 and Rab5 on membranes. Nat Commun 2021; 12:1564. [PMID: 33692360 PMCID: PMC7946940 DOI: 10.1038/s41467-021-21695-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/01/2021] [Indexed: 02/07/2023] Open
Abstract
The lipid phosphatidylinositol-3-phosphate (PI3P) is a regulator of two fundamental but distinct cellular processes, endocytosis and autophagy, so its generation needs to be under precise temporal and spatial control. PI3P is generated by two complexes that both contain the lipid kinase VPS34: complex II on endosomes (VPS34/VPS15/Beclin 1/UVRAG), and complex I on autophagosomes (VPS34/VPS15/Beclin 1/ATG14L). The endosomal GTPase Rab5 binds complex II, but the mechanism of VPS34 activation by Rab5 has remained elusive, and no GTPase is known to bind complex I. Here we show that Rab5a–GTP recruits endocytic complex II to membranes and activates it by binding between the VPS34 C2 and VPS15 WD40 domains. Electron cryotomography of complex II on Rab5a-decorated vesicles shows that the VPS34 kinase domain is released from inhibition by VPS15 and hovers over the lipid bilayer, poised for catalysis. We also show that the GTPase Rab1a, which is known to be involved in autophagy, recruits and activates the autophagy-specific complex I, but not complex II. Both Rabs bind to the same VPS34 interface but in a manner unique for each. These findings reveal how VPS34 complexes are activated on membranes by specific Rab GTPases and how they are recruited to unique cellular locations. The phosphatidylinositol-3-phosphate (PI3P) is generated by the lipid kinase VPS34, in the context of VPS34 complex I on autophagosomes or complex II on endosomes. Biochemical and structural analyses provide insights into the mechanism of both VPS34 complexes recruitment to and activation on membranes by specific Rab GTPases.
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Affiliation(s)
| | - Yohei Ohashi
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Dustin R Morado
- MRC Laboratory of Molecular Biology, Cambridge, UK.,Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | | | - Olga Perisic
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | | - Marie-Kristin von Wrisberg
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Lab for Synthetic Biochemistry, Technical University of Munich, Institute for Advanced Study, TUM-IAS, Garching, Germany
| | - Zhuo A Chen
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | | | | | - Mark Skehel
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Juri Rappsilber
- Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany.,Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Kathrin Lang
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Lab for Synthetic Biochemistry, Technical University of Munich, Institute for Advanced Study, TUM-IAS, Garching, Germany
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, UK.
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15
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Assembly and Cellular Exit of Coronaviruses: Hijacking an Unconventional Secretory Pathway from the Pre-Golgi Intermediate Compartment via the Golgi Ribbon to the Extracellular Space. Cells 2021; 10:cells10030503. [PMID: 33652973 PMCID: PMC7996754 DOI: 10.3390/cells10030503] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/18/2021] [Accepted: 02/18/2021] [Indexed: 12/20/2022] Open
Abstract
Coronaviruses (CoVs) assemble by budding into the lumen of the intermediate compartment (IC) at the endoplasmic reticulum (ER)-Golgi interface. However, why CoVs have chosen the IC as their intracellular site of assembly and how progeny viruses are delivered from this compartment to the extracellular space has remained unclear. Here we address these enigmatic late events of the CoV life cycle in light of recently described properties of the IC. Of particular interest are the emerging spatial and functional connections between IC elements and recycling endosomes (REs), defined by the GTPases Rab1 and Rab11, respectively. The establishment of IC-RE links at the cell periphery, around the centrosome and evidently also at the noncompact zones of the Golgi ribbon indicates that—besides traditional ER-Golgi communication—the IC also promotes a secretory process that bypasses the Golgi stacks, but involves its direct connection with the endocytic recycling system. The initial confinement of CoVs to the lumen of IC-derived large transport carriers and their preferential absence from Golgi stacks is consistent with the idea that they exit cells following such an unconventional route. In fact, CoVs may share this pathway with other intracellularly budding viruses, lipoproteins, procollagen, and/or protein aggregates experimentally introduced into the IC lumen.
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16
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Li F, Wu YW. Imaging of Spatial Cycling of Rab GTPase in the Cell. Methods Mol Biol 2021; 2293:105-115. [PMID: 34453713 DOI: 10.1007/978-1-0716-1346-7_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Rab GTPases (>60 members in human) function as master regulators of intracellular membrane trafficking. To fulfill their functions, Rab proteins need to localize on specific membranes in cells. It remains elusive how the distinct spatial distribution of Rab GTPases in the cell is regulated. To make a global assessment on the subcellular localization of Rab1, we determined kinetic parameters of the spatial cycling of Rab1 in live cells using photoactivatable fluorescent proteins and live cell imaging. We found that the switching between GTP- and GDP-binding states, which is governed by guanine nucleotide exchange factors (GEFs), GTPase activating proteins (GAPs), GDP dissociation inhibitor (GDI) and GDI displacement factor (GDF), is a major determinant for Rab1's ability to effectively cycle between cellular compartments and eventually for its subcellular distribution. Herein, we describe the method for monitoring Rab1 dynamics in live cells. This approach can be used to study spatial cycling of other Rab GTPases.
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Affiliation(s)
- Fu Li
- Max-Planck-Institute of Molecular Physiology, Dortmund, Germany
| | - Yao-Wen Wu
- Department of Chemistry, Uemå Centre for Microbial Research, Umeå University, Umeå, Sweden.
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17
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Fernandez-Chamorro J, Francisco-Velilla R, Ramajo J, Martinez-Salas E. Rab1b and ARF5 are novel RNA-binding proteins involved in FMDV IRES-driven RNA localization. Life Sci Alliance 2019; 2:e201800131. [PMID: 30655362 PMCID: PMC6337736 DOI: 10.26508/lsa.201800131] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 01/08/2019] [Accepted: 01/09/2019] [Indexed: 01/07/2023] Open
Abstract
Internal ribosome entry site (IRES) elements are organized in domains that guide internal initiation of translation. Here, we have combined proteomic and imaging analysis to study novel foot-and-mouth disease virus IRES interactors recognizing specific RNA structural subdomains. Besides known picornavirus IRES-binding proteins, we identified novel factors belonging to networks involved in RNA and protein transport. Among those, Rab1b and ARF5, two components of the ER-Golgi, revealed direct binding to IRES transcripts. However, whereas Rab1b stimulated IRES function, ARF5 diminished IRES activity. RNA-FISH studies revealed novel features of the IRES element. First, IRES-RNA formed clusters within the cell cytoplasm, whereas cap-RNA displayed disperse punctate distribution. Second, the IRES-driven RNA localized in close proximity with ARF5 and Rab1b, but not with the dominant-negative of Rab1b that disorganizes the Golgi. Thus, our data suggest a role for domain 3 of the IRES in RNA localization around ER-Golgi, a ribosome-rich cellular compartment.
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Affiliation(s)
- Javier Fernandez-Chamorro
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
| | - Rosario Francisco-Velilla
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
| | - Jorge Ramajo
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
| | - Encarnación Martinez-Salas
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
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18
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Abstract
The Golgi apparatus is a central sorting station in the cell. It receives newly synthesized molecules from the endoplasmic reticulum and directs them to different subcellular destinations, such as the plasma membrane or the endocytic pathway. Importantly, in the last few years, it has emerged that the maintenance of Golgi structure is connected to the proper regulation of membrane trafficking. Rab proteins are small GTPases that are considered to be the master regulators of the intracellular membrane trafficking. Several of the over 60 human Rabs are involved in the regulation of transport pathways at the Golgi as well as in the maintenance of its architecture. This chapter will summarize the different roles of Rab GTPases at the Golgi, both as regulators of membrane transport, scaffold, and tethering proteins and in preserving the structure and function of this organelle.
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19
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Saraste J, Marie M. Intermediate compartment (IC): from pre-Golgi vacuoles to a semi-autonomous membrane system. Histochem Cell Biol 2018; 150:407-430. [PMID: 30173361 PMCID: PMC6182704 DOI: 10.1007/s00418-018-1717-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2018] [Indexed: 12/19/2022]
Abstract
Despite its discovery more than three decades ago and well-established role in protein sorting and trafficking in the early secretory pathway, the intermediate compartment (IC) has remained enigmatic. The prevailing view is that the IC evolved as a specialized organelle to mediate long-distance endoplasmic reticulum (ER)–Golgi communication in metazoan cells, but is lacking in other eukaryotes, such as plants and fungi. However, this distinction is difficult to reconcile with the high conservation of the core machineries that regulate early secretory trafficking from yeast to man. Also, it has remained unclear whether the pleiomorphic IC components—vacuoles, tubules and vesicles—represent transient transport carriers or building blocks of a permanent pre-Golgi organelle. Interestingly, recent studies have revealed that the IC maintains its compositional, structural and spatial properties throughout the cell cycle, supporting a model that combines the dynamic and stable aspects of the organelle. Moreover, the IC has been assigned novel functions, such as cell signaling, Golgi-independent trafficking and autophagy. The emerging permanent nature of the IC and its connections with the centrosome and the endocytic recycling system encourage reconsideration of its relationship with the Golgi ribbon, role in Golgi biogenesis and ubiquitous presence in eukaryotic cells.
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Affiliation(s)
- Jaakko Saraste
- Department of Biomedicine and Molecular Imaging Center (MIC), University of Bergen, Jonas Lies vei 91, 5009, Bergen, Norway.
| | - Michaël Marie
- Department of Biomedicine and Molecular Imaging Center (MIC), University of Bergen, Jonas Lies vei 91, 5009, Bergen, Norway
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20
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Minamino N, Kanazawa T, Era A, Ebine K, Nakano A, Ueda T. RAB GTPases in the Basal Land Plant Marchantia polymorpha. PLANT & CELL PHYSIOLOGY 2018; 59:845-856. [PMID: 29444302 DOI: 10.1093/pcp/pcy027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/30/2018] [Indexed: 05/18/2023]
Abstract
The RAB GTPase is an evolutionarily conserved machinery component of membrane trafficking, which is the fundamental system for cell viability and higher order biological functions. The composition of RAB GTPases in each organism is closely related to the complexity and organization of the membrane trafficking pathway, which has been developed uniquely to realize the organism-specific membrane trafficking system. Comparative genomics has suggested that terrestrialization and/or multicellularization were associated with the expansion of membrane trafficking pathways in green plants, which has yet to be validated in basal land plant lineages. To obtain insight into the diversification of membrane trafficking systems in green plants, we analyzed RAB GTPases encoded in the genome of the liverwort Marchantia polymorpha in a comprehensive manner. We isolated all genes for RAB GTPases in Marchantia and analyzed their expression patterns and subcellular localizations in thallus cells. While a majority of MpRAB GTPases exhibited a ubiquitous expression pattern, specific exceptions were also observed; MpRAB2b, which contains a sequence similar to an intraflagellar transport protein at the C-terminal region; and MpRAB23, which has been secondarily lost in angiosperms, were specifically expressed in the male reproductive organ. MpRAB21, which is another RAB GTPase whose homolog is absent in Arabidopsis, exhibited endosomal localization with RAB5 members in Marchantia. These results suggest that Marchantia possesses unique membrane trafficking pathways involving a unique repertoire of RAB GTPases.
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Affiliation(s)
- Naoki Minamino
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
- Division of Cellular Dynamics, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi, 444-8585 Japan
| | - Takehiko Kanazawa
- Division of Cellular Dynamics, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi, 444-8585 Japan
- The Department of Basic Biology, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi, 444-8585 Japan
| | - Atsuko Era
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
| | - Kazuo Ebine
- Division of Cellular Dynamics, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi, 444-8585 Japan
- The Department of Basic Biology, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi, 444-8585 Japan
| | - Akihiko Nakano
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 Japan
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan
| | - Takashi Ueda
- Division of Cellular Dynamics, National Institute for Basic Biology, Nishigonaka 38, Myodaiji, Okazaki, Aichi, 444-8585 Japan
- The Department of Basic Biology, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi, 444-8585 Japan
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21
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Abstract
GTP-ases of the Rab family (about 70 in human) are key regulators of intracellular transport and membrane trafficking in eukaryotic cells. Remarkably, almost one third associate with membranes of the Golgi complex and TGN (trans-Golgi network). Through interactions with a variety of effectors that include molecular motors, tethering complexes, scaffolding proteins and lipid kinases, they play an important role in maintaining Golgi architecture.
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Affiliation(s)
- Bruno Goud
- a Institut Curie, PSL Research University, CNRS, UMR 144, Molecular Mechanisms of Intracellular Transport , Paris , France
| | - Shijie Liu
- b Department of Physiology and Biophysics , University of Arkansas for Medical Sciences , Little Rock , USA
| | - Brian Storrie
- b Department of Physiology and Biophysics , University of Arkansas for Medical Sciences , Little Rock , USA
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22
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Banworth MJ, Li G. Consequences of Rab GTPase dysfunction in genetic or acquired human diseases. Small GTPases 2017; 9:158-181. [PMID: 29239692 DOI: 10.1080/21541248.2017.1397833] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Rab GTPases are important regulators of intracellular membrane trafficking in eukaryotes. Both activating and inactivating mutations in Rab genes have been identified and implicated in human diseases ranging from neurological disorders to cancer. In addition, altered Rab expression is often associated with disease prognosis. As such, the study of diseases associated with Rabs or Rab-interacting proteins has shed light on the important role of intracellular membrane trafficking in disease etiology. In this review, we cover recent advances in the field with an emphasis on cellular mechanisms.
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Affiliation(s)
- Marcellus J Banworth
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| | - Guangpu Li
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
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23
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Golgi trafficking defects in postnatal microcephaly: The evidence for “Golgipathies”. Prog Neurobiol 2017; 153:46-63. [DOI: 10.1016/j.pneurobio.2017.03.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/22/2017] [Accepted: 03/29/2017] [Indexed: 12/17/2022]
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24
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Kranjc T, Dempsey E, Cagney G, Nakamura N, Shields DC, Simpson JC. Functional characterisation of the YIPF protein family in mammalian cells. Histochem Cell Biol 2016; 147:439-451. [DOI: 10.1007/s00418-016-1527-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/29/2016] [Indexed: 01/26/2023]
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25
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Martinez H, García IA, Sampieri L, Alvarez C. Spatial-Temporal Study of Rab1b Dynamics and Function at the ER-Golgi Interface. PLoS One 2016; 11:e0160838. [PMID: 27500526 PMCID: PMC4976911 DOI: 10.1371/journal.pone.0160838] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 07/26/2016] [Indexed: 12/27/2022] Open
Abstract
The GTPase Rab1b is involved in ER to Golgi transport, with multiple Rab1b effectors (located at ERES, VTCs and the Golgi complex) being required for its function. In this study, we performed live-cell dual-expression studies to analyze the dynamics of Rab1b and some effectors located at the ERES-Golgi interface. Rab1b occupied widely distributed mobile punctate and tubular structures, displaying a transient overlaps with its effectors and showing that these overlaps occurred at the same time in spatially distinct steps of ER to Golgi transport. In addition, we assessed Rab1b dynamics during cargo sorting by analyzing the concentration at ERES of a Golgi protein (SialT2-CFP) during Brefeldin A washout (BFA WO). Rab1b was associated to most of the ERES structures, but at different times during BFA WO, and recurrently SialT2-CFP was sorted in the ERES-Rab1b positive structures. Furthermore, we reveal for first time that Rab1b localization time at ERES depended on GBF1, a Rab1b effector that acts as the guanine nucleotide exchange factor of Arf1, and that Rab1b membrane association/dissociation dynamics at ERES was dependent on the GBF1 membrane association and activity, which strongly suggests that GBF1 activity modulates Rab1b membrane cycling dynamic.
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Affiliation(s)
- Hernán Martinez
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
| | - Iris A. García
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
| | - Luciana Sampieri
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
| | - Cecilia Alvarez
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
- * E-mail:
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26
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Morse D, Webster W, Kalanon M, Langsley G, McFadden GI. Plasmodium falciparum Rab1A Localizes to Rhoptries in Schizonts. PLoS One 2016; 11:e0158174. [PMID: 27348424 PMCID: PMC4922565 DOI: 10.1371/journal.pone.0158174] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 06/11/2016] [Indexed: 12/17/2022] Open
Abstract
Over-expression of a GFP-PfRab1A fusion protein in Plasmodium falciparum schizonts produces a punctate pattern of fluorescence typical of rhoptries, secretory organelles involved in host cell invasion. The GFP-positive bodies were purified by a combination of differential and density gradient centrifugation and their protein content determined by MS/MS sequencing. Consistent with the GFP rhoptry-like pattern of transgenic parasites, four of the 19 proteins identified have been previously described to be rhoptry-associated and another four are ER or ER-associated proteins. Confirmation that GFP-PfRab1A decorates rhoptries was obtained by its co-localization with Rap1 and Ron4 in late phase schizonts. We conclude that PfRab1A potentially regulates vesicular traffic from the endoplasmic reticulum to the rhoptries in Apicomplexa parasites.
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Affiliation(s)
- David Morse
- School of BioSciences, University of Melbourne, Melbourne, VIC, 3010, Australia
- * E-mail:
| | - Wesley Webster
- School of BioSciences, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Ming Kalanon
- School of BioSciences, University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Gordon Langsley
- Laboratoire de Biologie Cellulaire Comparative des Apicomplexes, Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris Descartes, 75014, Paris, France
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27
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Saraste J. Spatial and Functional Aspects of ER-Golgi Rabs and Tethers. Front Cell Dev Biol 2016; 4:28. [PMID: 27148530 PMCID: PMC4834429 DOI: 10.3389/fcell.2016.00028] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 03/23/2016] [Indexed: 12/13/2022] Open
Abstract
Two conserved Rab GTPases, Rab1 and Rab2, play important roles in biosynthetic-secretory trafficking between the endoplasmic reticulum (ER) and the Golgi apparatus in mammalian cells. Both are expressed as two isoforms that regulate anterograde transport via the intermediate compartment (IC) to the Golgi, but are also required for transport in the retrograde direction. Moreover, Rab1 has been implicated in the formation of autophagosomes. Rab1 and Rab2 have numerous effectors or partners that function in membrane tethering, but also have other roles. These include the coiled-coil proteins p115, GM130, giantin, golgin-84, and GMAP-210, as well as the multisubunit COG (conserved oligomeric Golgi) and TRAPP (transport protein particle) tethering complexes. TRAPP also acts as the GTP exchange factor (GEF) in the activation of Rab1. According to the traditional view of the IC elements as motile, transient structures, the functions of the Rabs could take place at the two ends of the ER-Golgi itinerary, i.e., at ER exit sites (ERES) and/or cis-Golgi. However, there is considerable evidence for their specific association with the IC, including its recently identified pericentrosomal domain (pcIC), where many of the effectors turn out to be present, thus being able to exert their functions at the pre-Golgi level. The IC localization of these proteins is of particular interest based on the imaging of Rab1 dynamics, indicating that the IC is a stable organelle that bidirectionally communicates with the ER and Golgi, and is functionally linked to the endosomal system via the pcIC.
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Affiliation(s)
- Jaakko Saraste
- Department of Biomedicine and Molecular Imaging Center, University of Bergen Bergen, Norway
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Yang XZ, Li XX, Zhang YJ, Rodriguez-Rodriguez L, Xiang MQ, Wang HY, Zheng XFS. Rab1 in cell signaling, cancer and other diseases. Oncogene 2016; 35:5699-5704. [PMID: 27041585 PMCID: PMC5396462 DOI: 10.1038/onc.2016.81] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 02/23/2016] [Accepted: 02/26/2016] [Indexed: 12/17/2022]
Abstract
The endoplasmic reticulum (ER) and Golgi membrane system have major roles in cell signaling and regulation of the biosynthesis/transport of proteins and lipids in response to environmental cues such as amino acid and cholesterol levels. Rab1 is the founding member of the Rab small GTPase family, which is known to mediate dynamic membrane trafficking between ER and Golgi. Growing evidence indicate that Rab1 proteins have important functions beyond their classical vesicular transport functions, including nutrient sensing and signaling, cell migration and presentation of cell-surface receptors. Moreover, deregulation of RAB1 expression has been linked to a myriad of human diseases such as cancer, cardiomyopathy and Parkinson's disease. Further investigating these new physiological and pathological functions of Rab1 should provide new opportunities for better understanding of the disease processes and may lead to more effective therapeutic interventions.
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Affiliation(s)
- X-Z Yang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - X-X Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Y-J Zhang
- Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.,Oncology Department, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - L Rodriguez-Rodriguez
- Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.,Department of Medicine, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
| | - M-Q Xiang
- Center for Advanced Biotechnology and Medicine, and Department of Pediatrics, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - H-Y Wang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China.,Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.,Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
| | - X F S Zheng
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China.,Rutgers Cancer Institute of New Jersey, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA.,Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, USA
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29
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Russo AJ, Mathiowetz AJ, Hong S, Welch MD, Campellone KG. Rab1 recruits WHAMM during membrane remodeling but limits actin nucleation. Mol Biol Cell 2016; 27:967-78. [PMID: 26823012 PMCID: PMC4791140 DOI: 10.1091/mbc.e15-07-0508] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 01/20/2016] [Indexed: 01/23/2023] Open
Abstract
Small G-proteins regulate the recruitment and activation of WASP-family actin nucleation factors at the plasma membrane. The G-protein Rab1 interacts with the nucleation factor WHAMM to remodel internal membranes into tubules. Unlike other G-proteins that recruit nucleation factors, Rab1 inhibits actin assembly. Small G-proteins are key regulatory molecules that activate the actin nucleation machinery to drive cytoskeletal rearrangements during plasma membrane remodeling. However, the ability of small G-proteins to interact with nucleation factors on internal membranes to control trafficking processes has not been well characterized. Here we investigated roles for members of the Rho, Arf, and Rab G-protein families in regulating WASP homologue associated with actin, membranes, and microtubules (WHAMM), an activator of Arp2/3 complex–mediated actin nucleation. We found that Rab1 stimulated the formation and elongation of WHAMM-associated membrane tubules in cells. Active Rab1 recruited WHAMM to dynamic tubulovesicular structures in fibroblasts, and an active prenylated version of Rab1 bound directly to an N-terminal domain of WHAMM in vitro. In contrast to other G-protein–nucleation factor interactions, Rab1 binding inhibited WHAMM-mediated actin assembly. This ability of Rab1 to regulate WHAMM and the Arp2/3 complex represents a distinct strategy for membrane remodeling in which a Rab G-protein recruits the actin nucleation machinery but dampens its activity.
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Affiliation(s)
- Ashley J Russo
- Department of Molecular and Cell Biology, Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Alyssa J Mathiowetz
- Department of Molecular and Cell Biology, Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Steven Hong
- Department of Molecular and Cell Biology, Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Matthew D Welch
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Kenneth G Campellone
- Department of Molecular and Cell Biology, Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
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30
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Saraste J, Marie M. Intermediate Compartment: A Sorting Station between the Endoplasmic Reticulum and the Golgi Apparatus. ENCYCLOPEDIA OF CELL BIOLOGY 2016. [PMCID: PMC7150006 DOI: 10.1016/b978-0-12-394447-4.20013-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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31
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Rab1-dependent ER-Golgi transport dysfunction is a common pathogenic mechanism in SOD1, TDP-43 and FUS-associated ALS. Acta Neuropathol 2015; 130:679-97. [PMID: 26298469 DOI: 10.1007/s00401-015-1468-2] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 08/11/2015] [Accepted: 08/12/2015] [Indexed: 12/12/2022]
Abstract
Several diverse proteins are linked genetically/pathologically to neurodegeneration in amyotrophic lateral sclerosis (ALS) including SOD1, TDP-43 and FUS. Using a variety of cellular and biochemical techniques, we demonstrate that ALS-associated mutant TDP-43, FUS and SOD1 inhibit protein transport between the endoplasmic reticulum (ER) and Golgi apparatus in neuronal cells. ER-Golgi transport was also inhibited in embryonic cortical and motor neurons obtained from a widely used animal model (SOD1(G93A) mice), validating this mechanism as an early event in disease. Each protein inhibited transport by distinct mechanisms, but each process was dependent on Rab1. Mutant TDP-43 and mutant FUS both inhibited the incorporation of secretory protein cargo into COPII vesicles as they bud from the ER, and inhibited transport from ER to the ER-Golgi intermediate (ERGIC) compartment. TDP-43 was detected on the cytoplasmic face of the ER membrane, whereas FUS was present within the ER, suggesting that transport is inhibited from the cytoplasm by mutant TDP-43, and from the ER by mutant FUS. In contrast, mutant SOD1 destabilised microtubules and inhibited transport from the ERGIC compartment to Golgi, but not from ER to ERGIC. Rab1 performs multiple roles in ER-Golgi transport, and over-expression of Rab1 restored ER-Golgi transport, and prevented ER stress, mSOD1 inclusion formation and induction of apoptosis, in cells expressing mutant TDP-43, FUS or SOD1. Rab1 also co-localised extensively with mutant TDP-43, FUS and SOD1 in neuronal cells, and Rab1 formed inclusions in motor neurons of spinal cords from sporadic ALS patients, which were positive for ubiquitinated TDP-43, implying that Rab1 is misfolded and dysfunctional in sporadic disease. These results demonstrate that ALS-mutant forms of TDP-43, FUS, and SOD1 all perturb protein transport in the early secretory pathway, between ER and Golgi compartments. These data also imply that restoring Rab1-mediated ER-Golgi transport is a novel therapeutic target in ALS.
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32
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Bardin S, Miserey-Lenkei S, Hurbain I, Garcia-Castillo D, Raposo G, Goud B. Phenotypic characterisation of RAB6A knockout mouse embryonic fibroblasts. Biol Cell 2015; 107:427-39. [PMID: 26304202 DOI: 10.1111/boc.201400083] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 08/18/2015] [Indexed: 01/08/2023]
Abstract
BACKGROUND INFORMATION Rab6 is one of the most conserved Rab GTPaes throughout evolution and the most abundant Rab protein associated with the Golgi complex. The two ubiquitous Rab isoforms, Rab6A and Rab6A', that are generated by alternative splicing of the RAB6A gene, regulate several transport steps at the Golgi level, including retrograde transport between endosomes and Golgi, anterograde transport between Golgi and the plasma membrane, and intra-Golgi and Golgi to endoplasmic reticulum transport. RESULTS We have generated mice with a conditional null allele of RAB6A. Mice homozygous for the RAB6A null allele died at an early stage of embryonic development. Mouse embryonic fibroblasts (MEFs) were isolated from RAB6A(loxP/loxP) Rosa26-CreERT2 and incubated with 4-hydroxy tamoxifen, resulting in the efficient depletion of Rab6A and Rab6A'. We show that Rab6 depletion affects cell growth, alters Golgi morphology and decreases the Golgi-associated levels of some known Rab6 effectors such as Bicaudal-D and myosin II. We also show that Rab6 depletion protects MEFs against ricin toxin and delays VSV-G secretion. CONCLUSIONS Our study shows that RAB6 is an essential gene required for normal embryonic development. We confirm in MEF cells most of the functions previously attributed to the two ubiquitous Rab6 isoforms.
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Affiliation(s)
- Sabine Bardin
- Institut Curie, PSL Research University and CNRS UMR 144, Paris, 75248, France
| | | | - Ilse Hurbain
- Institut Curie, PSL Research University and CNRS UMR 144, Paris, 75248, France
| | - Daniela Garcia-Castillo
- Institut Curie, PSL Research University, CNRS UMR 3666 and INSERM U1143, Paris, 75248, France
| | - Graça Raposo
- Institut Curie, PSL Research University and CNRS UMR 144, Paris, 75248, France
| | - Bruno Goud
- Institut Curie, PSL Research University and CNRS UMR 144, Paris, 75248, France
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Abstract
Whereas most of what we know today about the Ras-related small GTPases of the Rab family stems from observations made on Golgi complex, endosome and plasma membrane trafficking, a subset of Rabs localizes in part or predominantly to the ER (endoplasmic reticulum). Here, Rabs such as Rab1, Rab2, Rab6 and Rab33 can regulate the anterograde and retrograde trafficking of vesicles between the Golgi complex, the ERGIC (ER-Golgi intermediate compartment) and the ER itself. However, among the ER-associated Rabs, some Rabs appear to perform roles not directly related to trafficking: these Rabs (e.g. Rab32 or Rab24) could aid proteins of the atlastin and reticulon families in determining the extent and direction of ER tubulation. In so doing, these Rabs regulate not only ER contacts with other organelles such as mitochondria, but also the formation of autophagosomes.
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34
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Miller VJ, Sharma P, Kudlyk TA, Frost L, Rofe AP, Watson IJ, Duden R, Lowe M, Lupashin VV, Ungar D. Molecular insights into vesicle tethering at the Golgi by the conserved oligomeric Golgi (COG) complex and the golgin TATA element modulatory factor (TMF). J Biol Chem 2012; 288:4229-40. [PMID: 23239882 DOI: 10.1074/jbc.m112.426767] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein sorting between eukaryotic compartments requires vesicular transport, wherein tethering provides the first contact between vesicle and target membranes. Here we map and start to functionally analyze the interaction network of the conserved oligomeric Golgi (COG) complex that mediates retrograde tethering at the Golgi. The interactions of COG subunits with members of transport factor families assign the individual subunits as specific interaction hubs. Functional analysis of selected interactions suggests a mechanistic tethering model. We find that the COG complex interacts with two different Rabs in addition to each end of the golgin "TATA element modulatory factor" (TMF). This allows COG to potentially bridge the distance between the distal end of the golgin and the target membrane thereby promoting tighter docking. Concurrently we show that the central portion of TMF can bind to Golgi membranes that are liberated of their COPI cover. This latter interaction could serve to bring vesicle and target membranes into close apposition prior to fusion. A target selection mechanism, in which a hetero-oligomeric tethering factor organizes Rabs and coiled transport factors to enable protein sorting specificity, could be applicable to vesicle targeting throughout eukaryotic cells.
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Affiliation(s)
- Victoria J Miller
- Department of Biology, University of York, York, YO10 5DD, United Kingdom
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35
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Alcohol induces Golgi fragmentation in differentiated PC12 cells by deregulating Rab1-dependent ER-to-Golgi transport. Histochem Cell Biol 2012; 138:489-501. [PMID: 22614950 DOI: 10.1007/s00418-012-0970-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2012] [Indexed: 10/28/2022]
Abstract
In the present study, we analyze the effects of ethanol on the Golgi structure and membrane transport in differentiated PC12 cells, which are used as a model of neurons. Chronic exposure to moderate doses of ethanol induces Golgi fragmentation, a common characteristic of many neurodegenerative diseases. Alcohol impaired the lateral linking of stacks without causing microtubule damage. Extensive immunocytochemical and western blot analyses of representative Golgi proteins showed that few, but important, proteins are significantly affected. Thus, alcohol exposure induced a significant ER-to-Golgi transport delay, the retention of the GTPase Rab1 in the Golgi membranes and the accumulation of tethering factor p115 in the cytosol. These modifications would explain the observed fragmentation. The amount of p115 and the stacking protein GRASP65 increased in alcohol-treated cells, which might be a mechanism to reverse Golgi damage. Importantly, the overexpression of GTP-tagged Rab1 but not of a dominant-negative Rab1 mutant, restored the Golgi morphology, suggesting that this protein is the main target of alcohol. Taken together, our results support the view that alcohol and neurodegenerative diseases such as Parkinson have similar effects on intracellular trafficking and provide new clues on the neuropathology of alcoholism.
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36
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Liu S, Storrie B. Are Rab proteins the link between Golgi organization and membrane trafficking? Cell Mol Life Sci 2012; 69:4093-106. [PMID: 22581368 DOI: 10.1007/s00018-012-1021-6] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 04/18/2012] [Accepted: 04/24/2012] [Indexed: 11/25/2022]
Abstract
The fundamental separation of Golgi function between subcompartments termed cisternae is conserved across all eukaryotes. Likewise, Rab proteins, small GTPases of the Ras superfamily, are putative common coordinators of Golgi organization and protein transport. However, despite sequence conservation, e.g., Rab6 and Ypt6 are conserved proteins between humans and yeast, the fundamental organization of the organelle can vary profoundly. In the yeast Saccharomyces cerevisiae, the Golgi cisternae are physically separated from one another, while in mammalian cells, the cisternae are stacked one upon the other. Moreover, in mammalian cells, many Golgi stacks are typically linked together to generate a ribbon structure. Do evolutionarily conserved Rab proteins regulate secretory membrane trafficking and diverse Golgi organization in a common manner? In mammalian cells, some Golgi-associated Rab proteins function in coordination of protein transport and maintenance of Golgi organization. These include Rab6, Rab33B, Rab1, Rab2, Rab18, and Rab43. In yeast, these include Ypt1, Ypt32, and Ypt6. Here, based on evidence from both yeast and mammalian cells, we speculate on the essential role of Rab proteins in Golgi organization and protein transport.
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Affiliation(s)
- Shijie Liu
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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37
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García IA, Martinez HE, Alvarez C. Rab1b regulates COPI and COPII dynamics in mammalian cells. CELLULAR LOGISTICS 2011; 1:159-163. [PMID: 22279615 DOI: 10.4161/cl.1.4.18221] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/25/2011] [Accepted: 09/26/2011] [Indexed: 02/02/2023]
Abstract
Rabs GTPases are key regulatory factors that specifically associate to organelles that integrate membrane transport pathways. Rabs, through their interactions with diverse effector proteins, regulate the formation, movement, tethering and fusion of transport carriers (vesicles and/or tubules). The mammalian Rab1b GTPase is required for ER to Golgi transport and interacts with multiple effectors localized at the ER-Golgi interface. Here, we focus on interactions between Rab1b and effectors that play essential roles in COPII and COPI vesicle formation/function. Based on evidence to date, we propose a model of Rab1b action at the ER exit sites.
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Affiliation(s)
- Iris A García
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET); Departamento Bioquímica Clínica; Facultad de Ciencias Químicas; Universidad Nacional de Córdoba; Córdoba, Argentina
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Slavin I, García IA, Monetta P, Martinez H, Romero N, Alvarez C. Role of Rab1b in COPII dynamics and function. Eur J Cell Biol 2010; 90:301-11. [PMID: 21093099 DOI: 10.1016/j.ejcb.2010.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 10/04/2010] [Accepted: 10/04/2010] [Indexed: 12/27/2022] Open
Abstract
In eukaryotic cells, proteins destined for secretion are translocated into the endoplasmic reticulum (ER) and packaged into so-called COPII-coated vesicles. In the ER exit sites (ERES), COPII has the capacity of deforming the lipid bilayer, where it modulates the selective sorting and concentration of cargo proteins. In this study, we analyze the involvement of Rab1b in COPII dynamics and function by expressing either the Rab1b negative-mutant (Rab1N121I) or the Rab1b GTP restricted mutant (Rab1Q67L), or performing short interference RNA-based knockdown. We show that Rab1b interacts with the COPII components Sec23, Sec24 and Sec31 and that Rab1b inhibition changes the COPII phenotype. FRAP assays reveal that Rab1b modulates COPII association/dissociation kinetics at the ERES interface. Furthermore, Rab1b inhibition delays cargo sorting at the ER exit sites. We postulate that Rab1b is a key regulatory component of COPII dynamics and function.
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Affiliation(s)
- Ileana Slavin
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
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39
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The early secretory pathway contributes to the growth of the Coxiella-replicative niche. Infect Immun 2010; 79:402-13. [PMID: 20937765 DOI: 10.1128/iai.00688-10] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Coxiella burnetii is a Gram-negative obligate intracellular bacterium. After internalization, this bacterium replicates in a large parasitophorous vacuole that has features of both phagolysosomes and autophagosomal compartments. We have previously demonstrated that early after internalization Coxiella phagosomes interact with both the endocytic and the autophagic pathways. In this report, we present evidence that the Coxiella-replicative vacuoles (CRVs) also interact with the secretory pathway. Rab1b is a small GTPase responsible for the anterograde transport between the endoplasmic reticulum and the Golgi apparatus. We present evidence that Rab1b is recruited to the CRV at later infection times (i.e., after 6 h of infection). Interestingly, knockdown of Rab1b altered vacuole growth, indicating that this protein was required for the proper biogenesis of the CRV. In addition, overexpression of the active GTPase-defective mutant (GFP-Rab1b Q67L) affected the development of the Coxiella-replicative compartment inhibiting bacterial growth. On the other hand, disruption of the secretory pathway by brefeldin A treatment or by overexpression of Sar1 T39N, a defective dominant-negative mutant of Sar1, affected the typical spaciousness of the CRVs. Taken together, our results show for the first time that the Coxiella-replicative niche also intercepts the early secretory pathway.
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40
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Zoppino FCM, Militello RD, Slavin I, Alvarez C, Colombo MI. Autophagosome formation depends on the small GTPase Rab1 and functional ER exit sites. Traffic 2010; 11:1246-61. [PMID: 20545908 DOI: 10.1111/j.1600-0854.2010.01086.x] [Citation(s) in RCA: 199] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Autophagy is an important cellular degradation pathway present in all eukaryotic cells. Via this pathway, portions of the cytoplasm and/or organelles are sequestered in double-membrane structures called autophagosomes. In spite of the significant advance achieved in autophagy, the long-standing question about the source of the autophagic membrane remains unsolved. We have investigated the role of the secretory pathway in autophagosome biogenesis. Sar1 and Rab1b are monomeric GTPases that control traffic from the endoplasmic reticulum (ER) to the Golgi. We present evidence indicating that the activity of both proteins is required for autophagosome formation. Overexpression of dominant-negative mutants and the use of siRNAs impaired autophagosome generation as determined by LC3 puncta formation and light chain 3 (LC3)-II processing. In addition, our results indicate that the autophagic and secretory pathways intersect at a level preceding the brefeldin A blockage, suggesting that the transport from the cis/medial Golgi is not necessary for autophagosome biogenesis. Our present results highlight the role of transport from the ER in the initial events of the autophagic vacuole development.
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Affiliation(s)
- Felipe Carlos Martín Zoppino
- Instituto de Histología y Embriología (IHEM-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza 5500, Argentina
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41
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TGN golgins, Rabs and cytoskeleton: regulating the Golgi trafficking highways. Trends Cell Biol 2010; 20:329-36. [DOI: 10.1016/j.tcb.2010.02.006] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2009] [Revised: 02/15/2010] [Accepted: 02/17/2010] [Indexed: 12/22/2022]
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42
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Cell type-specific and light-dependent expression of Rab1 and Rab6 GTPases in mammalian retinas. Vis Neurosci 2009; 26:443-52. [PMID: 20003598 DOI: 10.1017/s0952523809990277] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The Ras-like Rab1 and Rab6 GTPases modulate protein traffic along the early secretory pathway and are involved in the regulation of maturation of rhodopsin in the outer retina. However, Rab GTPases have not been studied in the inner retinas. Here, we analyzed the anatomatic distribution and expression of Rab1 and Rab6 in the mouse and rat retinas by immunohistochemistry and immunoblotting. We found that Rab1 was specifically expressed in the rod bipolar cells, while Rab6 was expressed in a different cell type(s) from rod bipolar cells in the inner retina. We also demonstrated that expression of Rab1 and Rab6 was increased with light. These data provided the first evidence implicating that Rab1 and Rab6 may be involved in the regulation of the retinal adaptation.
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43
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Marie M, Dale HA, Sannerud R, Saraste J. The function of the intermediate compartment in pre-Golgi trafficking involves its stable connection with the centrosome. Mol Biol Cell 2009; 20:4458-70. [PMID: 19710425 PMCID: PMC2762134 DOI: 10.1091/mbc.e08-12-1229] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Revised: 08/18/2009] [Accepted: 08/19/2009] [Indexed: 01/03/2023] Open
Abstract
Because the functional borders of the intermediate compartment (IC) are not well defined, the spatial map of the transport machineries operating between the endoplasmic reticulum (ER) and the Golgi apparatus remains incomplete. Our previous studies showed that the IC consists of interconnected vacuolar and tubular parts with specific roles in pre-Golgi trafficking. Here, using live cell imaging, we demonstrate that the tubules containing the GTPase Rab1A create a long-lived membrane compartment around the centrosome. Separation of this pericentrosomal domain of the IC from the Golgi ribbon, due to centrosome motility, revealed that it contains a distinct pool of COPI coats and acts as a temperature-sensitive way station in post-ER trafficking. However, unlike the Golgi, the pericentrosomal IC resists the disassembly of COPI coats by brefeldin A, maintaining its juxtaposition with the endocytic recycling compartment, and operation as the focal point of a dynamic tubular network that extends to the cell periphery. These results provide novel insight into the compartmental organization of the secretory pathway and Golgi biogenesis. Moreover, they reveal a direct functional connection between the IC and the endosomal system, which evidently contributes to unconventional transport of the cystic fibrosis transmembrane conductance regulator to the cell surface.
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Affiliation(s)
- Michaël Marie
- Department of Biomedicine and Molecular Imaging Center, University of Bergen, N-5009 Bergen, Norway
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44
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Pinheiro H, Samalova M, Geldner N, Chory J, Martinez A, Moore I. Genetic evidence that the higher plant Rab-D1 and Rab-D2 GTPases exhibit distinct but overlapping interactions in the early secretory pathway. J Cell Sci 2009; 122:3749-58. [PMID: 19789181 DOI: 10.1242/jcs.050625] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
GTPases of the Rab1 subclass are essential for membrane traffic between the endoplasmic reticulum (ER) and Golgi complex in animals, fungi and plants. Rab1-related proteins in higher plants are unusual because sequence comparisons divide them into two putative subclasses, Rab-D1 and Rab-D2, that are conserved in monocots and dicots. We tested the hypothesis that the Rab-D1 and Rab-D2 proteins of Arabidopsis represent functionally distinct groups. RAB-D1 and RAB-D2a each targeted fluorescent proteins to the same punctate structures associated with the Golgi stacks and trans-Golgi-network. Dominant-inhibitory N121I mutants of each protein inhibited traffic of diverse cargo proteins at the ER but they appeared to act via distinct biochemical pathways as biosynthetic traffic in cells expressing either of the N121I mutants could be restored by coexpressing the wild-type form of the same subclass but not the other subclass. The same interaction was observed in transgenic seedlings expressing RAB-D1 [N121I]. Insertional mutants confirmed that the three Arabidopsis Rab-D2 genes were extensively redundant and collectively performed an essential function that could not be provided by RAB-D1, which was non-essential. However, plants lacking RAB-D1, RAB-D2b and RAB-D2c were short and bushy with low fertility, indicating that the Rab-D1 and Rab-D2 subclasses have overlapping functions.
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Affiliation(s)
- Hazel Pinheiro
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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Kano F, Yamauchi S, Yoshida Y, Watanabe-Takahashi M, Nishikawa K, Nakamura N, Murata M. Yip1A regulates the COPI-independent retrograde transport from the Golgi complex to the ER. J Cell Sci 2009; 122:2218-27. [PMID: 19509059 DOI: 10.1242/jcs.043414] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Yip1A, a mammalian homologue of yeast Yip1p, is a multi-spanning membrane protein that is considered to be involved in transport between the endoplasmic reticulum (ER) and the Golgi. However, the precise role of Yip1A in mammalian cells remains unclear. We show here that endogenous Yip1A is localized to the ER-Golgi intermediate compartment (ERGIC). Knockdown of Yip1A by RNAi did not induce morphological changes in the Golgi, ER, or ERGIC. By analyzing a number of intracellular transport pathways, we found that Yip1A knockdown delayed the transport of Shiga toxin from the Golgi to the ER, but did not affect the anterograde transport of VSVGts045. We also found that a recombinant protein that corresponded to the N-terminal domain of Yip1A inhibited the COPI-independent retrograde transport of GFP-tagged galactosyltransferase, GT-GFP, but not the COPI-dependent retrograde transport of p58/ERGIC53. Furthermore, we found that Yip1A knockdown resulted in the dissociation of Rab6 from the membranes. These results suggested that Yip1A has a role in COPI-independent retrograde transport from the Golgi to the ER and regulates the membrane recruitment of Rab6.
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Affiliation(s)
- Fumi Kano
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan
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Chapter 5: rab proteins and their interaction partners. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 274:235-74. [PMID: 19349039 DOI: 10.1016/s1937-6448(08)02005-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Ras superfamily consists of over 150 low molecular weight proteins that cycle between an inactive guanosine diphosphate (GDP)-bound state and an active guanosine triphosphate (GTP)-bound state. They are involved in a variety of signal transduction pathways that regulate cell growth, intracellular trafficking, cell migration, and apoptosis. Several methods have been devised to detect and characterize the interacting partners of small GTPases with the aim of better understanding their physiological function in normal cells and tumor cells. The Rab (Ras analog in brain) proteins form the largest family within the Ras superfamily. Rab proteins regulate vesicular trafficking pathways, behaving as membrane-associated molecular switches. The guanine nucleotide-binding status of Rab proteins is modulated by three different classes of regulatory proteins, which have been extensively studied for the Rab molecules but also for other subfamilies of the Ras superfamily. Furthermore, numerous effector molecules have been isolated especially for the Rab subfamily of proteins, which interact via a Rab-binding domain (RBD) and are recruited afterwards to specific sub-cellular compartments by the Rab proteins.
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Urwyler S, Nyfeler Y, Ragaz C, Lee H, Mueller LN, Aebersold R, Hilbi H. Proteome analysis of Legionella vacuoles purified by magnetic immunoseparation reveals secretory and endosomal GTPases. Traffic 2008; 10:76-87. [PMID: 18980612 DOI: 10.1111/j.1600-0854.2008.00851.x] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Legionella pneumophila, the causative agent of Legionnaires' disease, replicates in macrophages and amoebae within 'Legionella-containing vacuoles' (LCVs), which communicate with the early secretory pathway and the endoplasmic reticulum. Formation of LCVs requires the bacterial Icm/Dot type IV secretion system. The Icm/Dot-translocated effector protein SidC selectively anchors to LCVs by binding the host lipid phosphatidylinositol-4-phosphate (PtdIns(4)P). Here, we describe a novel and simple approach to purify intact vacuoles formed by L. pneumophila within Dictyostelium discoideum by using magnetic immunoseparation with an antibody against SidC, followed by density gradient centrifugation. To monitor LCV purification by fluorescence microscopy, we used Dictyostelium producing the LCV marker calnexin-GFP and L. pneumophila labeled with the red fluorescent protein DsRed. A proteome analysis of purified LCVs by liquid chromatography coupled to tandem mass spectrometry revealed 566 host proteins, including known LCV components, such as the small GTPases Arf1, Rab1 and Rab7. Rab8, an endosomal regulator of the late secretory pathway originating from the trans Golgi network, and the endosomal GTPase Rab14 were identified as novel LCV components, which were found to be present on vacuoles harboring wild-type but not Icm/Dot-deficient L. pneumophila. Thus, LCVs also communicate with the late secretory and endosomal pathways. Depletion of Rab8 or Arf1 by RNA interference reduced the amount of SidC on LCVs, indicating that the GTPases promote the recruitment of Legionella effectors by regulating the level of PtdIns(4)P.
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Affiliation(s)
- Simon Urwyler
- Institute of Microbiology, Department of Biology, ETH Zurich, Zurich, Switzerland
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Monetta P, Slavin I, Romero N, Alvarez C. Rab1b interacts with GBF1 and modulates both ARF1 dynamics and COPI association. Mol Biol Cell 2007; 18:2400-10. [PMID: 17429068 PMCID: PMC1924811 DOI: 10.1091/mbc.e06-11-1005] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Assembly of the cytosolic coat protein I (COPI) complex at the ER-Golgi interface is directed by the ADP ribosylation factor1 (Arf1) and its guanine nucleotide exchange factor (GBF1). Rab1b GTPase modulates COPI recruitment, but the molecular mechanism underlying this action remains unclear. Our data reveal that in vivo expression of the GTP-restricted Rab1b mutant (Rab1Q67L) increased the association of GBF1 and COPI to peripheral structures localized at the ER exit sites (ERES) interface. Active Rab1b also stabilized Arf1 on Golgi membranes. Furthermore, we characterized GBF1 as a new Rab1b effector, and showed that its N-terminal domain was involved in this interaction. Rab1b small interfering RNA oligonucleotide assays suggested that Rab1b was required for GBF1 membrane association. To further understand how Rab1b functions in ER-to-Golgi transport, we analyzed GFP-Rab1b dynamics in HeLa cells. Time-lapse microscopy indicated that the majority of the Rab1b-labeled punctuated structures are relatively short-lived with limited-range movements. FRAP of Golgi GFP-Rab1bwt showed rapid recovery (t(1/2) 120 s) with minimal dependence on microtubules. Our data support a model where Rab1b-GTP induces GBF1 recruitment at the ERES interface and at the Golgi complex where it is required for COPII/COPI exchange or COPI vesicle formation, respectively.
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Affiliation(s)
- Pablo Monetta
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, Departamento Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba 5000, Argentina
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Rosing M, Ossendorf E, Rak A, Barnekow A. Giantin interacts with both the small GTPase Rab6 and Rab1. Exp Cell Res 2007; 313:2318-25. [PMID: 17475246 DOI: 10.1016/j.yexcr.2007.03.031] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 03/16/2007] [Accepted: 03/27/2007] [Indexed: 01/21/2023]
Abstract
The interaction of small GTPases of the Rab family and coiled coil proteins of the golgin family has been reported for example for the Rab1 GTPase and p115, GM130 and Giantin. We now show that Rab6A, a GTPase that controls retrograde trafficking within the Golgi back to the endoplasmic reticulum is also able to bind to Giantin in vivo and in vitro pointing to an interesting complex formation between Giantin and two different Rab GTPases. In Saccharomyces cerevisiae a genetic interaction between Ypt1 and Ypt6 has already been demonstrated, but in this paper we were able to describe that the mammalian Rab GTPases are able to interact on the same golgin protein, Giantin.
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Affiliation(s)
- Mechthild Rosing
- University of Muenster, Department of Experimental Tumorbiology, University of Muenster, Badestr 9, Muenster, Germany
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Martínez-Alonso E, Ballesta J, Martínez-Menárguez JA. Low-Temperature-Induced Golgi Tubules Are Transient Membranes Enriched in Molecules Regulating Intra-Golgi Transport. Traffic 2007; 8:359-68. [PMID: 17274796 DOI: 10.1111/j.1600-0854.2006.00533.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The incubation of HeLa cells at 15 degrees C induces the formation of Golgi tubules, which contain glycosylation enzymes but neither cargo nor matrix proteins. We now show by immunofluorescence and immunoelectron microscopy that these tubules are enriched in a specific set of SNARE and Rab proteins mediating intra-Golgi transport (Gos28, GS15 and Rab6) but excluded others involved in endoplasmic reticulum-Golgi trafficking (Sec22, membrin, Rab 1 and Rab2). In vivo experiments using cyan fluorescent protein-tagged galactosyltransferase showed that most of these tubules are dynamic transient membranes that grow to the cell periphery but then decrease until disappearing into the perinuclear area. Interestingly, in experiments carried out with cells cultured under physiological conditions, Golgi tubules containing Gos28, GS15, Rab6 and glycosylation enzymes and showing in vivo dynamics identical to that detected in low-temperature-cultured cells were observed. Together, our results support that low-temperature-induced tubules may be representatives of the carriers mediating intra-Golgi recycling of enzymes.
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Affiliation(s)
- Emma Martínez-Alonso
- Department of Cell Biology, School of Medicine, University of Murcia, 30100 Murcia, Spain
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