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Malis Y, Armoza-Eilat S, Nevo-Yassaf I, Dukhovny A, Sklan EH, Hirschberg K. Rab1b facilitates lipid droplet growth by ER-to-lipid droplet targeting of DGAT2. SCIENCE ADVANCES 2024; 10:eade7753. [PMID: 38809969 PMCID: PMC11135398 DOI: 10.1126/sciadv.ade7753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2023] [Accepted: 04/16/2024] [Indexed: 05/31/2024]
Abstract
Lipid droplets (LDs) comprise a triglyceride core surrounded by a lipid monolayer enriched with proteins, many of which function in LD homeostasis. How proteins are targeted to the growing LD is still unclear. Rab1b, a GTPase regulating secretory transport, was recently associated with targeting proteins to LDs in a Drosophila RNAi screen. LD formation was prevented in human hepatoma cells overexpressing dominant-negative Rab1b. We thus hypothesized that Rab1b recruits lipid-synthesizing enzymes, facilitating LD growth. Here, FRET between diacylglycerol acyltransferase 2 (DGAT2) and Rab1b and activity mutants of the latter demonstrated that Rab1b promotes DGAT2 ER to the LD surface redistribution. Last, alterations in LD metabolism and DGAT2 redistribution, consistent with Rab1b activity, were caused by mutations in the Rab1b-GTPase activating protein TBC1D20 in Warburg Micro syndrome (WARBM) model mice fibroblasts. These data contribute to our understanding of the mechanism of Rab1b in LD homeostasis and WARBM, a devastating autosomal-recessive disorder caused by mutations in TBC1D20.
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Affiliation(s)
- Yehonathan Malis
- Department of Pathology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Shir Armoza-Eilat
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Inbar Nevo-Yassaf
- Department of Pathology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Anna Dukhovny
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ella H. Sklan
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Koret Hirschberg
- Department of Pathology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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Hall BA, Senior KE, Ocampo NT, Samanta D. Coxiella burnetii-containing vacuoles interact with host recycling endosomal proteins Rab11a and Rab35 for vacuolar expansion and bacterial growth. Front Cell Infect Microbiol 2024; 14:1394019. [PMID: 38841112 PMCID: PMC11150555 DOI: 10.3389/fcimb.2024.1394019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 05/01/2024] [Indexed: 06/07/2024] Open
Abstract
Introduction Coxiella burnetii is a gram-negative obligate intracellular bacterium and a zoonotic pathogen that causes human Q fever. The lack of effective antibiotics and a licensed vaccine for Coxiella in the U.S. warrants further research into Coxiella pathogenesis. Within the host cells, Coxiella replicates in an acidic phagolysosome-like vacuole termed Coxiella-containing vacuole (CCV). Previously, we have shown that the CCV pH is critical for Coxiella survival and that the Coxiella Type 4B secretion system regulates CCV pH by inhibiting the host endosomal maturation pathway. However, the trafficking pattern of the 'immature' endosomes in Coxiella- infected cells remained unclear. Methods We transfected HeLa cells with GFP-tagged Rab proteins and subsequently infected them with mCherry-Coxiella to visualize Rab protein localization. Infected cells were immunostained with anti-Rab antibodies to confirm the Rab localization to the CCV, to quantitate Rab11a and Rab35- positive CCVs, and to quantitate total recycling endosome content of infected cells. A dual-hit siRNA mediated knockdown combined with either immunofluorescent assay or an agarose-based colony-forming unit assay were used to measure the effects of Rab11a and Rab35 knockdown on CCV area and Coxiella intracellular growth. Results The CCV localization screen with host Rab proteins revealed that recycling endosome-associated proteins Rab11a and Rab35 localize to the CCV during infection, suggesting that CCV interacts with host recycling endosomes during maturation. Interestingly, only a subset of CCVs were Rab11a or Rab35-positive at any given time point. Quantitation of Rab11a/Rab35-positive CCVs revealed that while Rab11a interacts with the CCV more at 3 dpi, Rab35 is significantly more prevalent at CCVs at 6 dpi, suggesting that the CCV preferentially interacts with Rab11a and Rab35 depending on the stage of infection. Furthermore, we observed a significant increase in Rab11a and Rab35 fluorescent intensity in Coxiella-infected cells compared to mock, suggesting that Coxiella increases the recycling endosome content in infected cells. Finally, siRNA-mediated knockdown of Rab11a and Rab35 resulted in significantly smaller CCVs and reduced Coxiella intracellular growth, suggesting that recycling endosomal Rab proteins are essential for CCV expansion and bacterial multiplication. Discussion Our data, for the first time, show that the CCV dynamically interacts with host recycling endosomes for Coxiella intracellular survival and potentially uncovers novel host cell factors essential for Coxiella pathogenesis.
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Affiliation(s)
- Brooke A. Hall
- Department of Microbiology and Immunology, College of Graduate Studies, Midwestern University, Glendale, AZ, United States
| | - Kristen E. Senior
- Department of Microbiology and Immunology, College of Graduate Studies, Midwestern University, Glendale, AZ, United States
| | - Nicolle T. Ocampo
- Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, United States
| | - Dhritiman Samanta
- Department of Microbiology and Immunology, College of Graduate Studies, Midwestern University, Glendale, AZ, United States
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3
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Li GL, Han YQ, Su BQ, Yu HS, Zhang S, Yang GY, Wang J, Liu F, Ming SL, Chu BB. Porcine reproductive and respiratory syndrome virus 2 hijacks CMA-mediated lipolysis through upregulation of small GTPase RAB18. PLoS Pathog 2024; 20:e1012123. [PMID: 38607975 PMCID: PMC11014436 DOI: 10.1371/journal.ppat.1012123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 03/14/2024] [Indexed: 04/14/2024] Open
Abstract
RAB GTPases (RABs) control intracellular membrane trafficking with high precision. In the present study, we carried out a short hairpin RNA (shRNA) screen focused on a library of 62 RABs during infection with porcine reproductive and respiratory syndrome virus 2 (PRRSV-2), a member of the family Arteriviridae. We found that 13 RABs negatively affect the yield of PRRSV-2 progeny virus, whereas 29 RABs have a positive impact on the yield of PRRSV-2 progeny virus. Further analysis revealed that PRRSV-2 infection transcriptionally regulated RAB18 through RIG-I/MAVS-mediated canonical NF-κB activation. Disrupting RAB18 expression led to the accumulation of lipid droplets (LDs), impaired LDs catabolism, and flawed viral replication and assembly. We also discovered that PRRSV-2 co-opts chaperone-mediated autophagy (CMA) for lipolysis via RAB18, as indicated by the enhanced associations between RAB18 and perlipin 2 (PLIN2), CMA-specific lysosomal associated membrane protein 2A (LAMP2A), and heat shock protein family A (Hsp70) member 8 (HSPA8/HSC70) during PRRSV-2 infection. Knockdown of HSPA8 and LAMP2A impacted on the yield of PRRSV-2 progeny virus, implying that the virus utilizes RAB18 to promote CMA-mediated lipolysis. Importantly, we determined that the C-terminal domain (CTD) of HSPA8 could bind to the switch II domain of RAB18, and the CTD of PLIN2 was capable of associating with HSPA8, suggesting that HSPA8 facilitates the interaction between RAB18 and PLIN2 in the CMA process. In summary, our findings elucidate how PRRSV-2 hijacks CMA-mediated lipid metabolism through innate immune activation to enhance the yield of progeny virus, offering novel insights for the development of anti-PRRSV-2 treatments.
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Affiliation(s)
- Guo-Li Li
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, China
- Key Laboratory of Animal Biochemistry and Nutrition, Zhengzhou, Henan Province, Ministry of Agriculture and Rural Affairs of the People’s Republic of China
- Key Laboratory of Veterinary Biotechnology of Henan Province, Zhengzhou, Henan Province, China
| | - Ying-Qian Han
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, China
- Key Laboratory of Animal Biochemistry and Nutrition, Zhengzhou, Henan Province, Ministry of Agriculture and Rural Affairs of the People’s Republic of China
- Key Laboratory of Veterinary Biotechnology of Henan Province, Zhengzhou, Henan Province, China
| | - Bing-Qian Su
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, China
- Key Laboratory of Animal Biochemistry and Nutrition, Zhengzhou, Henan Province, Ministry of Agriculture and Rural Affairs of the People’s Republic of China
- Key Laboratory of Veterinary Biotechnology of Henan Province, Zhengzhou, Henan Province, China
| | - Hai-Shen Yu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, China
- Key Laboratory of Animal Biochemistry and Nutrition, Zhengzhou, Henan Province, Ministry of Agriculture and Rural Affairs of the People’s Republic of China
- Key Laboratory of Veterinary Biotechnology of Henan Province, Zhengzhou, Henan Province, China
| | - Shuang Zhang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, China
- Key Laboratory of Animal Biochemistry and Nutrition, Zhengzhou, Henan Province, Ministry of Agriculture and Rural Affairs of the People’s Republic of China
- Key Laboratory of Veterinary Biotechnology of Henan Province, Zhengzhou, Henan Province, China
| | - Guo-Yu Yang
- Key Laboratory of Animal Biochemistry and Nutrition, Zhengzhou, Henan Province, Ministry of Agriculture and Rural Affairs of the People’s Republic of China
- Key Laboratory of Veterinary Biotechnology of Henan Province, Zhengzhou, Henan Province, China
| | - Jiang Wang
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, China
- Key Laboratory of Animal Biochemistry and Nutrition, Zhengzhou, Henan Province, Ministry of Agriculture and Rural Affairs of the People’s Republic of China
- Key Laboratory of Veterinary Biotechnology of Henan Province, Zhengzhou, Henan Province, China
- Ministry of Education Key Laboratory for Animal Pathogens and Biosafety, Zhengzhou, Henan Province, China
| | - Fang Liu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, China
| | - Sheng-Li Ming
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, China
- Key Laboratory of Animal Biochemistry and Nutrition, Zhengzhou, Henan Province, Ministry of Agriculture and Rural Affairs of the People’s Republic of China
- Key Laboratory of Veterinary Biotechnology of Henan Province, Zhengzhou, Henan Province, China
| | - Bei-Bei Chu
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, Henan Province, China
- Key Laboratory of Animal Biochemistry and Nutrition, Zhengzhou, Henan Province, Ministry of Agriculture and Rural Affairs of the People’s Republic of China
- Key Laboratory of Veterinary Biotechnology of Henan Province, Zhengzhou, Henan Province, China
- Ministry of Education Key Laboratory for Animal Pathogens and Biosafety, Zhengzhou, Henan Province, China
- International Joint Research Center of National Animal Immunology, Henan Agricultural University, Zhengzhou, Henan Province, China
- Longhu Advanced Immunization Laboratory, Zhengzhou, Henan Province, China
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4
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Niedziółka SM, Datta S, Uśpieński T, Baran B, Skarżyńska W, Humke EW, Rohatgi R, Niewiadomski P. The exocyst complex and intracellular vesicles mediate soluble protein trafficking to the primary cilium. Commun Biol 2024; 7:213. [PMID: 38378792 PMCID: PMC10879184 DOI: 10.1038/s42003-024-05817-2] [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: 03/17/2022] [Accepted: 01/15/2024] [Indexed: 02/22/2024] Open
Abstract
The efficient transport of proteins into the primary cilium is a crucial step for many signaling pathways. Dysfunction of this process can lead to the disruption of signaling cascades or cilium assembly, resulting in developmental disorders and cancer. Previous studies on the protein delivery to the cilium were mostly focused on the membrane-embedded receptors. In contrast, how soluble proteins are delivered into the cilium is poorly understood. In our work, we identify the exocyst complex as a key player in the ciliary trafficking of soluble Gli transcription factors. In line with the known function of the exocyst in intracellular vesicle transport, we demonstrate that soluble proteins, including Gli2/3 and Lkb1, can use the endosome recycling machinery for their delivery to the primary cilium. Finally, we identify GTPases: Rab14, Rab18, Rab23, and Arf4 that are involved in vesicle-mediated Gli protein ciliary trafficking. Our data pave the way for a better understanding of ciliary transport and uncover transport mechanisms inside the cell.
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Affiliation(s)
- S M Niedziółka
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - S Datta
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - T Uśpieński
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - B Baran
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
- Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - W Skarżyńska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - E W Humke
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- IGM Biosciences, Inc, Mountain View, CA, USA
| | - R Rohatgi
- Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA
| | - P Niewiadomski
- Centre of New Technologies, University of Warsaw, Warsaw, Poland.
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5
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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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Lazki-Hagenbach P, Kleeblatt E, Fukuda M, Ali H, Sagi-Eisenberg R. The Underlying Rab Network of MRGPRX2-Stimulated Secretion Unveils the Impact of Receptor Trafficking on Secretory Granule Biogenesis and Secretion. Cells 2024; 13:93. [PMID: 38201297 PMCID: PMC10778293 DOI: 10.3390/cells13010093] [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: 12/02/2023] [Revised: 12/18/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
MRGPRX2, the human member of the MAS-related G-protein-coupled receptors (GPCRs), mediates the immunoglobulin E (IgE)-independent responses of a subset of mast cells (MCs) that are associated with itch, pain, neurogenic inflammation, and pseudoallergy to drugs. The mechanisms underlying the responses of MRGPRX2 to its multiple and diverse ligands are still not completely understood. Given the close association between GPCR location and function, and the key role played by Rab GTPases in controlling discrete steps along vesicular trafficking, we aimed to reveal the vesicular pathways that directly impact MRGPRX2-mediated exocytosis by identifying the Rabs that influence this process. For this purpose, we screened 43 Rabs for their functional and phenotypic impacts on MC degranulation in response to the synthetic MRGPRX2 ligand compound 48/80 (c48/80), which is often used as the gold standard of MRGPRX2 ligands, or to substance P (SP), an important trigger of neuroinflammatory MC responses. Results of this study highlight the important roles played by macropinocytosis and autophagy in controlling MRGPRX2-mediated exocytosis, demonstrating a close feedback control between the internalization and post-endocytic trafficking of MRGPRX2 and its triggered exocytosis.
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Affiliation(s)
- Pia Lazki-Hagenbach
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; (P.L.-H.); (E.K.)
| | - Elisabeth Kleeblatt
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; (P.L.-H.); (E.K.)
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai 980-8578, Miyagi, Japan;
| | - Hydar Ali
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA;
| | - Ronit Sagi-Eisenberg
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel; (P.L.-H.); (E.K.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
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7
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Sun J, Shao Y, Wang S, Li X, Feng S, Wang W, Leroy P, Li C, Zheng H. An Arabidopsis Rab18 GTPase promotes autophagy by tethering ATG18a to the ER in response to nutrient starvation. Dev Cell 2023; 58:2947-2958.e5. [PMID: 38056450 DOI: 10.1016/j.devcel.2023.11.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 07/30/2023] [Accepted: 11/10/2023] [Indexed: 12/08/2023]
Abstract
The expansion of autophagosomes requires a controlled association with the endoplasmic reticulum (ER). However, the mechanisms governing this process are not well defined. In plants, ATG18a plays a key role in autophagosome formation in response to stress, yet the factors regulating the process are unknown. This study finds that ATG18a acts as a downstream effector of RABC1, a member of the poorly characterized Rab18/RabC GTPase subclass in plants. Active RABC1 interacts with ATG18a on the ER, particularly under nutrient starvation. In rabc1 mutants, autophagy is compromised, especially under nutrient deprivation, affecting the ER association and expansion of ATG18a-positive autophagosomes. Furthermore, both dominant-negative and constitutively active RABC1 forms inhibit autophagy. The dominant inactive RABC1 impedes the ER association of ATG18a, whereas the constitutively active RABC1 delays ATG18a detachment from the ER. Collectively, RABC1 regulates the ER association and the subsequent detachment of ATG18a-positive autophagosomes during nutrient starvation.
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Affiliation(s)
- Jiaqi Sun
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, Shandong, China; Department of Biology, McGill University, Montreal, QC H3B 1A1, Canada.
| | - Yang Shao
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, Shandong, China
| | - Songyang Wang
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, Shandong, China
| | - Xunzheng Li
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, Shandong, China
| | - Shuqing Feng
- Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, Shandong, China
| | - Weina Wang
- Department of Biology, McGill University, Montreal, QC H3B 1A1, Canada
| | - Pierre Leroy
- Department of Biology, McGill University, Montreal, QC H3B 1A1, Canada
| | - Chengyang Li
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Huanquan Zheng
- Department of Biology, McGill University, Montreal, QC H3B 1A1, Canada.
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8
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Ghate PS, Vacharasin JM, Ward JA, Nowling D, Kay V, Cowen MH, Lawlor MK, McCord M, Xu H, Carmona E, Cheon SH, Chukwurah E, Walla M, Lizarraga SB. The Warburg micro syndrome protein RAB3GAP1 modulates neuronal morphogenesis and interacts with axon elongation end ER-Golgi trafficking factors. Neurobiol Dis 2023; 184:106215. [PMID: 37385458 DOI: 10.1016/j.nbd.2023.106215] [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: 08/03/2022] [Revised: 05/26/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023] Open
Abstract
RAB3GAP1 is GTPase activating protein localized to the ER and Golgi compartments. In humans, mutations in RAB3GAP1 are the most common cause of Warburg Micro syndrome, a neurodevelopmental disorder associated with intellectual disability, microcephaly, and agenesis of the corpus callosum. We found that downregulation of RAB3GAP1 leads to a reduction in neurite outgrowth and complexity in human stem cell derived neurons. To further define the cellular function of RAB3GAP1, we sought to identify novel interacting proteins. We used a combination of mass spectrometry, co-immunoprecipitation and colocalization analysis and identified two novel interactors of RAB3GAP1: the axon elongation factor Dedicator of cytokinesis 7 (DOCK7) and the TATA modulatory factor 1 (TMF1) a modulator of Endoplasmic Reticulum (ER) to Golgi trafficking. To define the relationship between RAB3GAP1 and its two novel interactors, we analyzed their localization to different subcellular compartments in neuronal and non-neuronal cells with loss of RAB3GAP1. We find that RAB3GAP1 is important for the sub-cellular localization of TMF1 and DOCK7 across different compartments of the Golgi and endoplasmic reticulum. In addition, we find that loss of function mutations in RAB3GAP1 lead to dysregulation of pathways that are activated in response to the cellular stress like ATF6, MAPK, and PI3-AKT signaling. In summary, our findings suggest a novel role for RAB3GAP1 in neurite outgrowth that could encompass the regulation of proteins that control axon elongation, ER-Golgi trafficking, as well as pathways implicated in response to cellular stress.
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Affiliation(s)
- Pankaj S Ghate
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Janay M Vacharasin
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Joseph A Ward
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, United States of America; Center for Translational Neuroscience, Brown University, Providence, RI, United states of America
| | - Duncan Nowling
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Valerie Kay
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Mara H Cowen
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Mary-Kate Lawlor
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Mikayla McCord
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Hailey Xu
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Esteban Carmona
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Seon-Hye Cheon
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Evelyn Chukwurah
- Department of Biology and Center for Childhood Neurotherapeutics, University of South Carolina, Columbia, SC, United States of America
| | - Mike Walla
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC, United States of America
| | - Sofia B Lizarraga
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, United States of America; Center for Translational Neuroscience, Brown University, Providence, RI, United states of America.
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9
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Ge S, Zhang RX, Wang YF, Sun P, Chu J, Li J, Sun P, Wang J, Hetherington AM, Liang YK. The Arabidopsis Rab protein RABC1 affects stomatal development by regulating lipid droplet dynamics. THE PLANT CELL 2022; 34:4274-4292. [PMID: 35929087 PMCID: PMC9614440 DOI: 10.1093/plcell/koac239] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/13/2022] [Indexed: 05/13/2023]
Abstract
Lipid droplets (LDs) are evolutionarily conserved organelles that serve as hubs of cellular lipid and energy metabolism in virtually all organisms. Mobilization of LDs is important in light-induced stomatal opening. However, whether and how LDs are involved in stomatal development remains unknown. We show here that Arabidopsis thaliana LIPID DROPLETS AND STOMATA 1 (LDS1)/RABC1 (At1g43890) encodes a member of the Rab GTPase family that is involved in regulating LD dynamics and stomatal morphogenesis. The expression of RABC1 is coordinated with the different phases of stomatal development. RABC1 targets to the surface of LDs in response to oleic acid application in a RABC1GEF1-dependent manner. RABC1 physically interacts with SEIPIN2/3, two orthologues of mammalian seipin, which function in the formation of LDs. Disruption of RABC1, RABC1GEF1, or SEIPIN2/3 resulted in aberrantly large LDs, severe defects in guard cell vacuole morphology, and stomatal function. In conclusion, these findings reveal an aspect of LD function and uncover a role for lipid metabolism in stomatal development in plants.
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Affiliation(s)
| | | | - Yi-Fei Wang
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Pengyue Sun
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Jiaheng Chu
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jiao Li
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Peng Sun
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jianbo Wang
- State Key Laboratory of Hybrid Rice, Department of Plant Sciences, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Alistair M Hetherington
- School of Biological Sciences, Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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10
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Lu J, Swearingen E, Hardy M, Collins P, Wu B, Yuan E, Lu D, Li CM, Wang S, Ollmann M. RAB18 is a key regulator of GalNAc-conjugated siRNA-induced silencing in Hep3B cells. MOLECULAR THERAPY - NUCLEIC ACIDS 2022; 28:423-434. [PMID: 35505960 PMCID: PMC9035644 DOI: 10.1016/j.omtn.2022.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 04/01/2022] [Indexed: 12/19/2022]
Abstract
Small interfering RNA (siRNA) therapeutics have developed rapidly in recent years, despite the challenges associated with delivery of large, highly charged nucleic acids. Delivery of siRNA therapeutics to the liver has been established, with conjugation of siRNA to N-acetylgalactosamine (GalNAc) providing durable gene knockdown in hepatocytes following subcutaneous injection. GalNAc binds the asialoglycoprotein receptor (ASGPR) that is highly expressed on hepatocytes and exploits this scavenger receptor to deliver siRNA across the plasma membrane by endocytosis. However, siRNA needs to access the RNA-induced silencing complex (RISC) in the cytoplasm to provide effective gene knockdown, and the entire siRNA delivery process is very inefficient, likely because of steps required for endosomal escape, intracellular trafficking, and stability of siRNA. To reveal the cellular factors limiting delivery of siRNA therapeutics, we performed a genome-wide pooled knockout screen on the basis of delivery of GalNAc-conjugated siRNA targeting the HPRT1 gene in the human hepatocellular carcinoma line Hep3B. Our primary genome-wide pooled knockout screen identified candidate genes that when knocked out significantly enhanced siRNA efficacy in Hep3B cells. Follow-up studies indicate that knockout of RAB18 improved the efficacy of siRNA delivered by GalNAc, cholesterol, or antibodies, but not siRNA delivered by Lipofectamine transfection, suggesting a role for RAB18 in siRNA delivery and intracellular trafficking.
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11
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Bae WJ, Woo KJ, Ahn JM, Yang CM, Kim YS, Kim S, Lee D. miR-4742-5p promotes invasiveness of gastric cancer via targeting Rab43: An in vitro study. Biochem Biophys Res Commun 2022; 613:180-186. [PMID: 35597125 DOI: 10.1016/j.bbrc.2022.05.044] [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: 04/27/2022] [Accepted: 05/12/2022] [Indexed: 11/02/2022]
Abstract
miRNA (miR)-4742-5p is a recently identified microRNA regarding progression and metastasis in gastric cancer (GC). However, the biological function of this novel miRNA is largely unknown. We identified that the miR-4742-5p expression level was variably increased in GC cell lines. Suppression of miR-4742-5p using miR-inhibitor reduced the proliferation, migration, and invasion of GC cells with high miR-4742-5p expression, whereas overexpression of miR-4742-5p-mimic enhanced the aforementioned properties in GC cells with low miR-4742-5p expression. miR-4742-5p expression induced the decreases of Zo-1 and E-cadherin expression as well as the increases of vimentin and N-cadherin expression, leading to epithelial-mesenchymal transition (EMT) of cancer cells. RNA sequencing results indicated Ras-related GTP-binding protein 43 (Rab43) as a potential target gene. We identified that the expression of Rab43 is associated with activation of AKT and nuclear factor-kappa B (NF-κB) which are key oncogenic pathways in cancer cells. Our results demonstrate a new component in GC progression, promising a potential therapeutic strategy.
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Affiliation(s)
- Won Jung Bae
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Kyoung-Jin Woo
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea; Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Ji Mi Ahn
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Chan-Mo Yang
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea; Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - You-Sun Kim
- Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea; Department of Biochemistry, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Seokhwi Kim
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea; Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea.
| | - Dakeun Lee
- Department of Pathology, Ajou University School of Medicine, Suwon, Republic of Korea; Department of Biomedical Sciences, Ajou University Graduate School of Medicine, Suwon, Republic of Korea.
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12
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Casey CA, Macke AJ, Gough RR, Pachikov AN, Morris ME, Thomes PG, Kubik JL, Holzapfel MS, Petrosyan A. Alcohol-Induced Liver Injury: Down-regulation and Redistribution of Rab3D Results in Atypical Protein Trafficking. Hepatol Commun 2022; 6:374-388. [PMID: 34494400 PMCID: PMC8793998 DOI: 10.1002/hep4.1811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/05/2021] [Accepted: 08/05/2021] [Indexed: 12/17/2022] Open
Abstract
Previous work from our laboratories has identified multiple defects in endocytosis, protein trafficking, and secretion, along with altered Golgi function after alcohol administration. Manifestation of alcohol-associated liver disease (ALD) is associated with an aberrant function of several hepatic proteins, including asialoglycoprotein receptor (ASGP-R), their atypical distribution at the plasma membrane (PM), and secretion of their abnormally glycosylated forms into the bloodstream, but trafficking mechanism is unknown. Here we report that a small GTPase, Rab3D, known to be involved in exocytosis, secretion, and vesicle trafficking, shows ethanol (EtOH)-impaired function, which plays an important role in Golgi disorganization. We used multiple approaches and cellular/animal models of ALD, along with Rab3D knockout (KO) mice and human tissue from patients with ALD. We found that Rab3D resides primarily in trans- and cis-faces of Golgi; however, EtOH treatment results in Rab3D redistribution from trans-Golgi to cis-medial-Golgi. Cells lacking Rab3D demonstrate enlargement of Golgi, especially its distal compartments. We identified that Rab3D is required for coat protein I (COPI) vesiculation in Golgi, and conversely, COPI is critical for intra-Golgi distribution of Rab3D. Rab3D/COPI association was altered not only in the liver of patients with ALD but also in the donors consuming alcohol without steatosis. In Rab3D KO mice, hepatocytes experience endoplasmic reticulum (ER) stress, and EtOH administration activates apoptosis. Notably, in these cells, ASGP-R, despite incomplete glycosylation, can still reach cell surface through ER-PM junctions. This mimics the effects seen with EtOH-induced liver injury. Conclusion: We revealed that down-regulation of Rab3D contributes significantly to EtOH-induced Golgi disorganization, and abnormally glycosylated ASGP-R is excreted through ER-PM connections, bypassing canonical (ER→Golgi→PM) anterograde transportation. This suggests that ER-PM sites may be a therapeutic target for ALD.
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Affiliation(s)
- Carol A. Casey
- Department of Research ServiceOmaha Western Iowa Health Care System, VA ServiceOmahaNEUSA
- Department of Internal MedicineUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Amanda J. Macke
- Department of Biochemistry and Molecular BiologyUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Ryan R. Gough
- Department of Research ServiceOmaha Western Iowa Health Care System, VA ServiceOmahaNEUSA
- Department of Internal MedicineUniversity of Nebraska Medical CenterOmahaNEUSA
- Department of Biochemistry and Molecular BiologyUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Artem N. Pachikov
- Department of Biochemistry and Molecular BiologyUniversity of Nebraska Medical CenterOmahaNEUSA
- The Fred and Pamela Buffett Cancer CenterOmahaNEUSA
| | - Mary E. Morris
- Department of Biochemistry and Molecular BiologyUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Paul G. Thomes
- Department of Research ServiceOmaha Western Iowa Health Care System, VA ServiceOmahaNEUSA
- Department of Internal MedicineUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Jacy L. Kubik
- Department of Research ServiceOmaha Western Iowa Health Care System, VA ServiceOmahaNEUSA
- Department of Internal MedicineUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Melissa S. Holzapfel
- Department of Pathology and MicrobiologyUniversity of Nebraska Medical CenterOmahaNEUSA
| | - Armen Petrosyan
- Department of Biochemistry and Molecular BiologyUniversity of Nebraska Medical CenterOmahaNEUSA
- The Fred and Pamela Buffett Cancer CenterOmahaNEUSA
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13
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Connected function of PRAF/RLD and GNOM in membrane trafficking controls intrinsic cell polarity in plants. Nat Commun 2022; 13:7. [PMID: 35013279 PMCID: PMC8748900 DOI: 10.1038/s41467-021-27748-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 12/09/2021] [Indexed: 12/13/2022] Open
Abstract
Cell polarity is a fundamental feature underlying cell morphogenesis and organismal development. In the Arabidopsis stomatal lineage, the polarity protein BASL controls stomatal asymmetric cell division. However, the cellular machinery by which this intrinsic polarity site is established remains unknown. Here, we identify the PRAF/RLD proteins as BASL physical partners and mutating four PRAF members leads to defects in BASL polarization. Members of PRAF proteins are polarized in stomatal lineage cells in a BASL-dependent manner. Developmental defects of the praf mutants phenocopy those of the gnom mutants. GNOM is an activator of the conserved Arf GTPases and plays important roles in membrane trafficking. We further find PRAF physically interacts with GNOM in vitro and in vivo. Thus, we propose that the positive feedback of BASL and PRAF at the plasma membrane and the connected function of PRAF and GNOM in endosomal trafficking establish intrinsic cell polarity in the Arabidopsis stomatal lineage.
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14
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Lei Z, Wang J, Zhang L, Liu CH. Ubiquitination-Dependent Regulation of Small GTPases in Membrane Trafficking: From Cell Biology to Human Diseases. Front Cell Dev Biol 2021; 9:688352. [PMID: 34277632 PMCID: PMC8281112 DOI: 10.3389/fcell.2021.688352] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/09/2021] [Indexed: 01/04/2023] Open
Abstract
Membrane trafficking is critical for cellular homeostasis, which is mainly carried out by small GTPases, a class of proteins functioning in vesicle budding, transport, tethering and fusion processes. The accurate and organized membrane trafficking relies on the proper regulation of small GTPases, which involves the conversion between GTP- and GDP-bound small GTPases mediated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Emerging evidence indicates that post-translational modifications (PTMs) of small GTPases, especially ubiquitination, play an important role in the spatio-temporal regulation of small GTPases, and the dysregulation of small GTPase ubiquitination can result in multiple human diseases. In this review, we introduce small GTPases-mediated membrane trafficking pathways and the biological processes of ubiquitination-dependent regulation of small GTPases, including the regulation of small GTPase stability, activity and localization. We then discuss the dysregulation of small GTPase ubiquitination and the associated human membrane trafficking-related diseases, focusing on the neurological diseases and infections. An in-depth understanding of the molecular mechanisms by which ubiquitination regulates small GTPases can provide novel insights into the membrane trafficking process, which knowledge is valuable for the development of more effective and specific therapeutics for membrane trafficking-related human diseases.
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Affiliation(s)
- Zehui Lei
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
| | - Jing Wang
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China
| | - Lingqiang Zhang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Cui Hua Liu
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Beijing, China.,Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China
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15
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Deng Y, Zhou C, Mirza AH, Bamigbade AT, Zhang S, Xu S, Liu P. Rab18 binds PLIN2 and ACSL3 to mediate lipid droplet dynamics. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:158923. [PMID: 33713834 DOI: 10.1016/j.bbalip.2021.158923] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 02/26/2021] [Accepted: 03/05/2021] [Indexed: 01/16/2023]
Abstract
Lipid droplet (LD) is a vital organelle governing lipid homeostasis and Rab18 has been linked to lipid metabolism. However, the mechanisms of Rab18-mediated LD dynamics in myoblast cells remain elusive. Here, we report that Rab18 plays an important role in oleic acid (OA)-induced LD accumulation in mouse myoblast C2C12 cells. Rab18 was translocated from the endoplasmic reticulum (ER) to LDs during LD accumulation, which was regulated by perilipin 2 (PLIN2), a major LD protein. LD-associated Rab18 bound with the C terminus of PLIN2 and the LD localization of Rab18 was diminished when PLIN2 was depleted. Moreover, loss of function of Rab18 led to reduced triacylglycerol (TAG) level and fewer but larger LDs. In contrast, overexpression of Rab18 resulted in elevated TAG content and LD number. Furthermore, LD-associated Rab18 interacted with acyl-CoA synthetase long-chain family member 3 (ACSL3), which in turn promoted the LD localization of this protein. These data show that Rab18 interacts with PLIN2 and forms a complex with PLIN2 and ACSL3, which plays a critical role in LD accumulation and dynamics of myoblast cells.
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Affiliation(s)
- Yaqin Deng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chang Zhou
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ahmed Hammad Mirza
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Adekunle T Bamigbade
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuyan Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Shimeng Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
| | - Pingsheng Liu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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16
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Shomron O, Nevo-Yassaf I, Aviad T, Yaffe Y, Zahavi EE, Dukhovny A, Perlson E, Brodsky I, Yeheskel A, Pasmanik-Chor M, Mironov A, Beznoussenko GV, Mironov AA, Sklan EH, Patterson GH, Yonemura Y, Sannai M, Kaether C, Hirschberg K. COPII collar defines the boundary between ER and ER exit site and does not coat cargo containers. J Cell Biol 2021; 220:211990. [PMID: 33852719 PMCID: PMC8054201 DOI: 10.1083/jcb.201907224] [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: 07/31/2019] [Revised: 01/14/2021] [Accepted: 03/11/2021] [Indexed: 12/13/2022] Open
Abstract
COPII and COPI mediate the formation of membrane vesicles translocating in opposite directions within the secretory pathway. Live-cell and electron microscopy revealed a novel mode of function for COPII during cargo export from the ER. COPII is recruited to membranes defining the boundary between the ER and ER exit sites, facilitating selective cargo concentration. Using direct observation of living cells, we monitored cargo selection processes, accumulation, and fission of COPII-free ERES membranes. CRISPR/Cas12a tagging, the RUSH system, and pharmaceutical and genetic perturbations of ER-Golgi transport demonstrated that the COPII coat remains bound to the ER–ERES boundary during protein export. Manipulation of the cargo-binding domain in COPII Sec24B prohibits cargo accumulation in ERES. These findings suggest a role for COPII in selecting and concentrating exported cargo rather than coating Golgi-bound carriers. These findings transform our understanding of coat proteins’ role in ER-to-Golgi transport.
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Affiliation(s)
- Olga Shomron
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Inbar Nevo-Yassaf
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Tamar Aviad
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Yakey Yaffe
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Eitan Erez Zahavi
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Anna Dukhovny
- Department of Clinical Immunology and Microbiology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Eran Perlson
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - Ilya Brodsky
- Lomonosov Moscow State University, Andrey N. Belozersky Institute for Physico-Chemical Biology, Moscow, Russia
| | - Adva Yeheskel
- Bioinformatics Unit, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Metsada Pasmanik-Chor
- Bioinformatics Unit, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel Aviv, Israel
| | - Anna Mironov
- Istituto Firc di Oncologia Molecolare, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan, Italy
| | - Galina V Beznoussenko
- Istituto Firc di Oncologia Molecolare, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan, Italy
| | - Alexander A Mironov
- Istituto Firc di Oncologia Molecolare, Fondazione Istituto Fondazione Italiana per la Ricerca sul Cancro di Oncologia Molecolare, Milan, Italy
| | - Ella H Sklan
- Department of Clinical Immunology and Microbiology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
| | - George H Patterson
- Section on Biophotonics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Rockville, MD
| | - Yoji Yonemura
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | - Mara Sannai
- Leibniz Institute on Aging, Fritz Lipmann Institute, Jena, Germany
| | | | - Koret Hirschberg
- Department of Pathology, Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel
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17
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Wei Z, Xu X, Fang Y, Khater M, Naughton SX, Hu G, Terry AV, Wu G. Rab43 GTPase directs postsynaptic trafficking and neuron-specific sorting of G protein-coupled receptors. J Biol Chem 2021; 296:100517. [PMID: 33676895 PMCID: PMC8050390 DOI: 10.1016/j.jbc.2021.100517] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/25/2021] [Accepted: 03/03/2021] [Indexed: 12/31/2022] Open
Abstract
G protein–coupled receptors (GPCRs) are important modulators of synaptic functions. A fundamental but poorly addressed question in neurobiology is how targeted GPCR trafficking is achieved. Rab GTPases are the master regulators of vesicle-mediated membrane trafficking, but their functions in the synaptic presentation of newly synthesized GPCRs are virtually unknown. Here, we investigate the role of Rab43, via dominant-negative inhibition and CRISPR–Cas9–mediated KO, in the export trafficking of α2-adrenergic receptor (α2-AR) and muscarinic acetylcholine receptor (mAChR) in primary neurons and cells. We demonstrate that Rab43 differentially regulates the overall surface expression of endogenous α2-AR and mAChR, as well as their signaling, in primary neurons. In parallel, Rab43 exerts distinct effects on the dendritic and postsynaptic transport of specific α2B-AR and M3 mAChR subtypes. More interestingly, the selective actions of Rab43 toward α2B-AR and M3 mAChR are neuronal cell specific and dictated by direct interaction. These data reveal novel, neuron-specific functions for Rab43 in the dendritic and postsynaptic targeting and sorting of GPCRs and imply multiple forward delivery routes for different GPCRs in neurons. Overall, this study provides important insights into regulatory mechanisms of GPCR anterograde traffic to the functional destination in neurons.
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Affiliation(s)
- Zhe Wei
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Xin Xu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Yinquan Fang
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA; Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Mostafa Khater
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Sean X Naughton
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Gang Hu
- Department of Pharmacology, Nanjing Medical University, Nanjing, China
| | - Alvin V Terry
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | - Guangyu Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, Georgia, USA.
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18
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Zhang L, Zhao D, Jin M, Song M, Liu S, Guo K, Zhang Y. Rab18 binds to classical swine fever virus NS5A and mediates viral replication and assembly in swine umbilical vein endothelial cells. Virulence 2021; 11:489-501. [PMID: 32419589 PMCID: PMC7239025 DOI: 10.1080/21505594.2020.1767356] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Classical swine fever virus (CSFV), a positive-sense RNA virus, hijacks cell host proteins for its own replication. Rab18, a small Rab GTPase, regulates intracellular membrane-trafficking events between various compartments in cells and is involved in the life cycle of multiple viruses. However, the effect of Rab18 on the production of CSFV remains uncertain. In this study, we showed that knockdown of Rab18 by lentiviruses inhibited CSFV production, while overexpression of Rab18 by lentiviruses enhanced CSFV production. Subsequent experiments revealed that the negative-mutant Rab18-S22 N inhibited CSFV infection, while the positive-mutant Rab18-Q67 L enhanced CSFV infection. Furthermore, we showed that CSFV RNA replication and virion assembly, measured by real-time fluorescence quantitative PCR (RT-qPCR), indirect immunofluorescence assay (IFA), and confocal microscopy, were reduced in cells lacking Rab18 expression. In addition, co-immunoprecipitation, GST-pulldown, and confocal microscopy assays revealed that Rab18 bound to the viral protein NS5A. Further, NS5A was shown to be redistributed in Rab18 knockdown cells. Taken together, these findings demonstrate Rab18 as a novel host factor required for CSFV RNA replication and particle assembly by interaction with the viral protein NS5A.
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Affiliation(s)
- Liang Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Di Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Mingxing Jin
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Mengzhao Song
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Shanchuan Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Kangkang Guo
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Yanming Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
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19
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Deffieu MS, Cesonyte I, Delalande F, Boncompain G, Dorobantu C, Song E, Lucansky V, Hirschler A, Cianferani S, Perez F, Carapito C, Gaudin R. Rab7-harboring vesicles are carriers of the transferrin receptor through the biosynthetic secretory pathway. SCIENCE ADVANCES 2021; 7:7/2/eaba7803. [PMID: 33523982 PMCID: PMC7793588 DOI: 10.1126/sciadv.aba7803] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 11/18/2020] [Indexed: 06/07/2023]
Abstract
The biosynthetic secretory pathway is particularly challenging to investigate as it is underrepresented compared to the abundance of the other intracellular trafficking routes. Here, we combined the retention using selective hook (RUSH) to a CRISPR-Cas9 gene editing approach (eRUSH) and identified Rab7-harboring vesicles as an important intermediate compartment of the Golgi-to-plasma membrane transport of neosynthesized transferrin receptor (TfR). These vesicles did not exhibit degradative properties and were not associated to Rab6A-harboring vesicles. Rab7A was transiently associated to neosynthetic TfR-containing post-Golgi vesicles but dissociated before fusion with the plasma membrane. Together, our study reveals a role for Rab7 in the biosynthetic secretory pathway of the TfR, highlighting the diversity of the secretory vesicles' nature.
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Affiliation(s)
- Maika S Deffieu
- Institut de Recherche en Infectiologie de Montpellier (IRIM) CNRS, Univ Montpellier, 34293 Montpellier, France.
- INSERM, Univ Strasbourg, 67000 Strasbourg, France
| | | | - François Delalande
- Laboratoire de Spectrométrie de Masse Bio-Organique, IPHC, UMR 7178, CNRS-Université de Strasbourg, ECPM, 67087 Strasbourg, France
| | - Gaelle Boncompain
- Institut Curie, PSL Research University, Sorbonne Université, Centre National de la Recherche Scientifique, UMR 144, 26 rue d'Ulm, F-75005 Paris, France
| | | | - Eli Song
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | | | - Aurélie Hirschler
- Laboratoire de Spectrométrie de Masse Bio-Organique, IPHC, UMR 7178, CNRS-Université de Strasbourg, ECPM, 67087 Strasbourg, France
| | - Sarah Cianferani
- Laboratoire de Spectrométrie de Masse Bio-Organique, IPHC, UMR 7178, CNRS-Université de Strasbourg, ECPM, 67087 Strasbourg, France
| | - Franck Perez
- Institut Curie, PSL Research University, Sorbonne Université, Centre National de la Recherche Scientifique, UMR 144, 26 rue d'Ulm, F-75005 Paris, France
| | - Christine Carapito
- Laboratoire de Spectrométrie de Masse Bio-Organique, IPHC, UMR 7178, CNRS-Université de Strasbourg, ECPM, 67087 Strasbourg, France
| | - Raphael Gaudin
- Institut de Recherche en Infectiologie de Montpellier (IRIM) CNRS, Univ Montpellier, 34293 Montpellier, France.
- INSERM, Univ Strasbourg, 67000 Strasbourg, France
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20
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Cancer-driving mutations and variants of components of the membrane trafficking core machinery. Life Sci 2020; 264:118662. [PMID: 33127517 DOI: 10.1016/j.lfs.2020.118662] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/17/2020] [Accepted: 10/22/2020] [Indexed: 12/12/2022]
Abstract
The core machinery for vesicular membrane trafficking broadly comprises of coat proteins, RABs, tethering complexes and SNAREs. As cellular membrane traffic modulates key processes of mitogenic signaling, cell migration, cell death and autophagy, its dysregulation could potentially results in increased cell proliferation and survival, or enhanced migration and invasion. Changes in the levels of some components of the core machinery of vesicular membrane trafficking, likely due to gene amplifications and/or alterations in epigenetic factors (such as DNA methylation and micro RNA) have been extensively associated with human cancers. Here, we provide an overview of association of membrane trafficking with cancer, with a focus on mutations and variants of coat proteins, RABs, tethering complex components and SNAREs that have been uncovered in human cancer cells/tissues. The major cellular and molecular cancer-driving or suppression mechanisms associated with these components of the core membrane trafficking machinery shall be discussed.
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21
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Rab6 is required for rapid, cisternal-specific, intra-Golgi cargo transport. Sci Rep 2020; 10:16604. [PMID: 33024151 PMCID: PMC7538953 DOI: 10.1038/s41598-020-73276-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 08/28/2020] [Indexed: 11/08/2022] Open
Abstract
Rab6, the most abundant Golgi associated small GTPase, consists of 2 equally common isoforms, Rab6A and Rab6A′, that differ in 3 amino acids and localize to trans Golgi cisternae. The two isoforms are largely redundant in function and hence are often referred to generically as Rab6. Rab6 loss-of-function inhibits retrograde Golgi trafficking, induces an increase in Golgi cisternal number in HeLa cells and delays the cell surface appearance of the anterograde cargo protein, VSVG. We hypothesized that these effects are linked and might be explained by a cisternal-specific delay in cargo transport. In pulse chase experiments using a deconvolved, confocal line scanning approach to score the distribution of the tsO45 mutant of VSVG protein in Rab6 depleted cells, we found that anterograde transport at 32 °C, permissive conditions, through the Golgi apparatus was locally delayed, almost tenfold, between medial and trans Golgi cisterna. Cis to medial transport was nearly normal as was trans Golgi to TGN transport. TGN exit was unaffected by Rab6 depletion. These effects were the same with either of two siRNAs. Similar intra-Golgi transport delays were seen at 37 °C with RUSH VSVG or a RUSH GPI-anchored construct using a biotin pulse to release the marker proteins from the ER. Using 3D-SIM, a super resolution approach, we found that RUSH VSVG transport was delayed pre-trans Golgi. These visual approaches suggest a selective slowing of anterograde transport relative to 3 different marker proteins downstream of the trans Golgi. Using a biochemical approach, we found that the onset of VSVG endoglycosidase H resistance in Rab6 depleted cells was delayed. Depletion of neither Rab6A or Rab6A′ isoforms alone had any effect on anterograde transport through the Golgi suggesting that Rab6A and Rab6A′ act coordinately. Delayed cargo transport conditions correlate strongly with a proliferation of Golgi cisternae observed in earlier electron microscopy. Our results strongly indicate that Rab6 is selectively required for rapid anterograde transport from the medial to trans Golgi. We suggest that the observed correlation with localized cisternal proliferation fits best with a cisternal progression model of Golgi function.
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22
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Dejgaard SY, Presley JF. Class II Arfs require a brefeldin-A-sensitive factor for Golgi association. Biochem Biophys Res Commun 2020; 530:301-306. [PMID: 32828303 DOI: 10.1016/j.bbrc.2020.07.001] [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: 06/18/2020] [Accepted: 07/01/2020] [Indexed: 10/23/2022]
Abstract
Arf proteins are small Ras-family GTPases which recruit clathrin and COPI coats to Golgi membranes and regulate components of the membrane trafficking machinery. It is believed membrane association and activity of Arfs is coupled to GTP binding, with GTP hydrolysis required for vesicle uncoating. In humans, four Arf proteins (Arf1, Arf3, Arf4 and Arf5) are Golgi-associated. Conflicting reports have suggested that HA-GFP-tagged Class II ARFs (Arf4 and Arf5) are recruited to membrane independently of the brefeldin A sensitive exchange factor GBF1, suggesting regulation fundamentally different from the Class I Arfs (Arf1, Arf3), or alternately that the GTPase cycle of GFP-tagged Class II Arfs is similar to other Arfs. We show that these results depend on the fluorescent tag, with Arf4-HA-GFP tag resistant to brefeldin, but Arf4-GFP acting similarly to Arf1-GFP in brefeldin-sensitivity and photobleach assays. Arf4-HA-GFP could be partially reverted to the behavior of Arf4-GFP by mutation of two aspartic acids in the HA tag to alanine. Our results, which indicate a high sensitivity of Arf4 to tagging, can explain the discrepancies between previous studies. We discuss the implications of this study for future work with tagged Arfs.
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Affiliation(s)
- Selma Y Dejgaard
- Department of Anatomy & Cell Biology, McGill University, 3640 University Street, 1/28 Strathcona, Montreal, QC, H3A 0C7, Canada; Department of Medical Biology, Near East University, Nicosia, Cyprus
| | - John F Presley
- Department of Anatomy & Cell Biology, McGill University, 3640 University Street, 1/28 Strathcona, Montreal, QC, H3A 0C7, Canada.
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23
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Guadagno NA, Margiotta A, Bjørnestad SA, Haugen LH, Kjos I, Xu X, Hu X, Bakke O, Margadant F, Progida C. Rab18 regulates focal adhesion dynamics by interacting with kinectin-1 at the endoplasmic reticulum. J Cell Biol 2020; 219:151855. [PMID: 32525992 PMCID: PMC7337506 DOI: 10.1083/jcb.201809020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 07/17/2019] [Accepted: 03/26/2020] [Indexed: 12/13/2022] Open
Abstract
The members of the Rab family of small GTPases are molecular switches that regulate distinct steps in different membrane traffic pathways. In addition to this canonical function, Rabs can play a role in other processes, such as cell adhesion and motility. Here, we reveal the role of the small GTPase Rab18 as a positive regulator of directional migration in chemotaxis, and the underlying mechanism. We show that knockdown of Rab18 reduces the size of focal adhesions (FAs) and influences their dynamics. Furthermore, we found that Rab18, by directly interacting with the endoplasmic reticulum (ER)-resident protein kinectin-1, controls the anterograde kinesin-1–dependent transport of the ER required for the maturation of nascent FAs and protrusion orientation toward a chemoattractant. Altogether, our data support a model in which Rab18 regulates kinectin-1 transport toward the cell surface to form ER–FA contacts, thus promoting FA growth and cell migration during chemotaxis.
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Affiliation(s)
| | | | | | | | - Ingrid Kjos
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Xiaochun Xu
- Mechanobiology Institute, National University of Singapore, Singapore
| | - Xian Hu
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Oddmund Bakke
- Department of Biosciences, University of Oslo, Oslo, Norway
| | - Felix Margadant
- Mechanobiology Institute, National University of Singapore, Singapore
| | - Cinzia Progida
- Department of Biosciences, University of Oslo, Oslo, Norway
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24
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Zhang L, Wang T, Song M, Jin M, Liu S, Guo K, Zhang Y. Rab1b-GBF1-ARFs mediated intracellular trafficking is required for classical swine fever virus replication in swine umbilical vein endothelial cells. Vet Microbiol 2020; 246:108743. [PMID: 32605744 DOI: 10.1016/j.vetmic.2020.108743] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/22/2020] [Accepted: 05/31/2020] [Indexed: 01/24/2023]
Abstract
Classical swine fever virus (CSFV), a plus-sense RNA virus, utilizes host intracellular membrane organelles for its replication. Our previous studies have shown that disruption of the intracellular membrane-trafficking events can inhibit CSFV replication. However, the underlying mechanism of this process in CSFV infection has not been elucidated. To determine the role of Golgi-associated anterograde and retrograde trafficking in CSFV replication, we revealed the effect of vesicular transport between Golgi and ER inhibitors Brefeldin A (BFA) and 2,2-methyl-N-(2,4,6,-trimethoxyphenyl) dodecanamide (CI-976), the GBF1 inhibitor golgicide A (GCA) on virus production. Our results showed that disruption of vesicular trafficking by BFA, CI-976, and GCA significantly inhibited CSFV infection. Subsequent experiments revealed that knockdown of Rab1b by lentiviruses and negative-mutant Rab1b-N121I transfection inhibited CSFV infection. Furthermore, we showed that the Rab1b downstream vesicular component effectors GBF1, and class I and class II ADP-ribosylation factors (ARFs) were also involved in virus replication. In addition, confocal microscopy assay showed that CSFV infection disrupted the Golgi apparatus resulting in extended Golgi distribution around the nucleus. We also showed that cell secretory pathway, measured using Gaussia luciferase flash assay, was blocked in CSFV infected cells. Taken together, these findings demonstrate that CSFV utilizes Rab1b-GBF1-ARFs mediated trafficking to promote its own replication. These findings also provide new insights into the intracellular trafficking pathways utilized for CSFV life cycle.
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Affiliation(s)
- Liang Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Tao Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Mengzhao Song
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Mingxing Jin
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Shanchuan Liu
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Kangkang Guo
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, China.
| | - Yanming Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, China.
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25
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Takáts S, Lévay L, Boda A, Tóth S, Simon-Vecsei Z, Rubics A, Varga Á, Lippai M, Lőrincz P, Glatz G, Juhász G. The Warburg Micro Syndrome-associated Rab3GAP-Rab18 module promotes autolysosome maturation through the Vps34 Complex I. FEBS J 2020; 288:190-211. [PMID: 32248620 DOI: 10.1111/febs.15313] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 02/10/2020] [Accepted: 03/26/2020] [Indexed: 12/23/2022]
Abstract
Warburg micro syndrome (WMS) is a hereditary autosomal neuromuscular disorder in humans caused by mutations in Rab18, Rab3GAP1, or Rab3GAP2 genes. Rab3GAP1/2 forms a heterodimeric complex, which acts as a guanosine nucleotide exchange factor and activates Rab18. Although the genetic causes of WMS are known, it is still unclear whether loss of the Rab3GAP-Rab18 module affects neuronal or muscle cell physiology or both, and how. In this work, we characterize a Rab3GAP2 mutant Drosophila line to establish a novel animal model for WMS. Similarly to symptoms of WMS, loss of Rab3GAP2 leads to highly decreased motility in Drosophila that becomes more serious with age. We demonstrate that these mutant flies are defective for autophagic degradation in multiple tissues including fat cells and muscles. Loss of Rab3GAP-Rab18 module members leads to perturbed autolysosome morphology due to destabilization of Rab7-positive autophagosomal and late endosomal compartments and perturbation of lysosomal biosynthetic transport. Importantly, overexpression of UVRAG or loss of Atg14, two alternative subunits of the Vps34/PI3K (vacuole protein sorting 34/phosphatidylinositol 3-kinase) complexes in fat cells, mimics the autophagic phenotype of Rab3GAP-Rab18 module loss. We find that GTP-bound Rab18 binds to Atg6/Beclin1, a permanent subunit of Vps34 complexes. Finally, we show that Rab3GAP2 and Rab18 are present on autophagosomal and autolysosomal membranes and colocalize with Vps34 Complex I subunits. Our data suggest that the Rab3GAP-Rab18 module regulates autolysosomal maturation through its interaction with the Vps34 Complex I, and perturbed autophagy due to loss of the Rab3GAP-Rab18 module may contribute to the development of WMS.
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Affiliation(s)
- Szabolcs Takáts
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Premium Postdoctorate Research Program, Hungarian Academy of Sciences, Budapest, Hungary
| | - Luca Lévay
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Attila Boda
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Sarolta Tóth
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Zsófia Simon-Vecsei
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - András Rubics
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Ágnes Varga
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Mónika Lippai
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Péter Lőrincz
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Premium Postdoctorate Research Program, Hungarian Academy of Sciences, Budapest, Hungary
| | - Gábor Glatz
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Institute of Genetics, Biological Research Centre of the Hungarian Academy of Sciences, Szeged, Hungary
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26
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Huang Z, Liang H, Chen L. RAB43 Promotes Gastric Cancer Cell Proliferation and Metastasis via Regulating the PI3K/AKT Signaling Pathway. Onco Targets Ther 2020; 13:2193-2202. [PMID: 32210585 PMCID: PMC7073444 DOI: 10.2147/ott.s237356] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 03/01/2020] [Indexed: 01/29/2023] Open
Abstract
Background Ras-related GTP-binding protein 43 (RAB43) plays a key part in the progression of many human cancers. However, the role and functional mechanisms of RAB43 in gastric cancer (GC) remain unknown. Purpose To elucidate the function and mechanism of RAB43 in the progression of GC. Patients and Methods One hundred patients with histologically confirmed GC were recruited for this study. Tumor samples and GC cell lines were used to detect RAB43 levels. Cell Counting Kit8 (CCK8) and colony formation assays were used to analyze cell proliferation. Cell migration and invasion ability were examined by wound healing and transwell assays. Western blot assays and quantitative real‑time PCR (qRT-PCR) were performed to examine related mRNA and protein expression. In vivo experiments were used to examine the effect of RAB43. Results Patients with RAB43-positive tumors had worse overall survival than patients with RAB43-negative tumors. Downregulation of RAB43 significantly inhibited cell proliferation and cell metastasis. In contrast, RAB43 overexpression promoted proliferation and metastasis in normal gastric epithelial GES‑1 cells. In vivo studies confirmed that RAB43 promoted tumor growth. In addition, the knockdown of RAB43 significantly inhibited cell proliferation and metastasis via phosphatidylinositol-3-kinases/protein-serine-threonine kinase (PI3K/AKT) pathway. Conclusion RAB43 promotes GC cells proliferation and migration in vivo and in vitro and probably served as a novel potential therapeutic biomarker for GC.
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Affiliation(s)
- Zhiye Huang
- Department of General Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, People's Republic of China
| | - Haibin Liang
- Department of General Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, People's Republic of China
| | - Lei Chen
- Department of General Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, People's Republic of China
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27
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Abstract
The mammalian Golgi apparatus is a highly dynamic organelle, which is normally localized in the juxtanuclear space and plays an essential role in the regulation of cellular homeostasis. While posttranslational modification of cargo is mediated by the resident enzymes (glycosyltransferases, glycosidases, and kinases), the ribbon structure of Golgi and its cisternal stacking mostly rely on the cooperation of coiled-coil matrix golgins. Among them, giantin, GM130, and GRASPs are unique, because they form a tripartite complex and serve as Golgi docking sites for cargo delivered from the endoplasmic reticulum (ER). Golgi undergoes significant disorganization in many pathologies associated with a block of the ER-to-Golgi or intra-Golgi transport, including cancer, different neurological diseases, alcoholic liver damage, ischemic stress, viral infections, etc. In addition, Golgi fragments during apoptosis and mitosis. Here, we summarize and analyze clinically relevant observations indicating that Golgi fragmentation is associated with the selective loss of Golgi residency for some enzymes and, conversely, with the relocation of some cytoplasmic proteins to the Golgi. The central concept is that ER and Golgi stresses impair giantin docking site but have no impact on the GM130-GRASP65 complex, thus inducing mislocalization of giantin-sensitive enzymes only. This cardinally changes the processing of proteins by eliminating the pathways controlled by the missing enzymes and by activating the processes now driven by the GM130-GRASP65-dependent proteins. This type of Golgi disorganization is different from the one induced by the cytoskeleton alteration, which despite Golgi de-centralization, neither impairs function of golgins nor alters trafficking.
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Affiliation(s)
- A Petrosyan
- College of Medicine, Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA. .,The Nebraska Center for Integrated Biomolecular Communication, Lincoln, NE 68588, USA.,The Fred and Pamela Buffett Cancer Center, Omaha, NE 68106, USA
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28
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Coulter ME, Dorobantu CM, Lodewijk GA, Delalande F, Cianferani S, Ganesh VS, Smith RS, Lim ET, Xu CS, Pang S, Wong ET, Lidov HGW, Calicchio ML, Yang E, Gonzalez DM, Schlaeger TM, Mochida GH, Hess H, Lee WCA, Lehtinen MK, Kirchhausen T, Haussler D, Jacobs FMJ, Gaudin R, Walsh CA. The ESCRT-III Protein CHMP1A Mediates Secretion of Sonic Hedgehog on a Distinctive Subtype of Extracellular Vesicles. Cell Rep 2020; 24:973-986.e8. [PMID: 30044992 PMCID: PMC6178983 DOI: 10.1016/j.celrep.2018.06.100] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 04/18/2018] [Accepted: 06/24/2018] [Indexed: 01/23/2023] Open
Abstract
Endosomal sorting complex required for transport (ESCRT) complex proteins regulate biogenesis and release of extracellular vesicles (EVs), which enable cell-to-cell communication in the nervous system essential for development and adult function. We recently showed human loss-of-function (LOF) mutations in ESCRT-III member CHMP1A cause autosomal recessive microcephaly with pontocerebellar hypoplasia, but its mechanism was unclear. Here, we show Chmp1a is required for progenitor proliferation in mouse cortex and cerebellum and progenitor maintenance in human cerebral organoids. In Chmp1a null mice, this defect is associated with impaired sonic hedgehog (Shh) secretion and intraluminal vesicle (ILV) formation in multivesicular bodies (MVBs). Furthermore, we show CHMP1A is important for release of an EV subtype that contains AXL, RAB18, and TMED10 (ART) and SHH. Our findings show CHMP1A loss impairs secretion of SHH on ART-EVs, providing molecular mechanistic insights into the role of ESCRT proteins and EVs in the brain. Extracellular vesicles (EVs) are essential for cell-to-cell communication in developing brain. Coulter et al. show that the human microcephaly gene CHMP1A is required for neuroprogenitor proliferation through regulation of vesicular secretion of the growth factor sonic hedgehog (SHH). CHMP1A specifically impairs SHH secretion on a distinctive EV subtype, ART-EV.
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Affiliation(s)
- Michael E Coulter
- Division of Genetics and Genomics and Howard Hughes Medical Institute, Boston Children's Hospital, Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Program in Neuroscience and Harvard/MIT MD-PHD Program, Harvard Medical School, Boston, MA 02115, USA
| | - Cristina M Dorobantu
- Inserm U1110, Université de Strasbourg, Institut de Recherche sur les Maladies Virales et Hépatiques, 67000 Strasbourg, France
| | - Gerrald A Lodewijk
- University of Amsterdam, Swammerdam Institute for Life Sciences, 1098 XH Amsterdam, the Netherlands
| | - François Delalande
- Laboratoire de Spectrométrie de Masse Bio-Organique, IPHC, UMR 7178, CNRS-Université de Strasbourg, ECPM, 67087 Strasbourg, France
| | - Sarah Cianferani
- Laboratoire de Spectrométrie de Masse Bio-Organique, IPHC, UMR 7178, CNRS-Université de Strasbourg, ECPM, 67087 Strasbourg, France
| | - Vijay S Ganesh
- Division of Genetics and Genomics and Howard Hughes Medical Institute, Boston Children's Hospital, Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Richard S Smith
- Division of Genetics and Genomics and Howard Hughes Medical Institute, Boston Children's Hospital, Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Elaine T Lim
- Division of Genetics and Genomics and Howard Hughes Medical Institute, Boston Children's Hospital, Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - C Shan Xu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Song Pang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Eric T Wong
- Brain Tumor Center and Neuro-Oncology Unit, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Hart G W Lidov
- Department of Pathology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Monica L Calicchio
- Department of Pathology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Edward Yang
- Department of Radiology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Dilenny M Gonzalez
- Division of Genetics and Genomics and Howard Hughes Medical Institute, Boston Children's Hospital, Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Thorsten M Schlaeger
- Division of Hematology and Oncology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Ganeshwaran H Mochida
- Division of Genetics and Genomics and Howard Hughes Medical Institute, Boston Children's Hospital, Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA; Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Harald Hess
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Wei-Chung Allen Lee
- F.M. Kirby Neurobiology Center, Boston Children's Hospital and Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Maria K Lehtinen
- Department of Pathology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Tomas Kirchhausen
- Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - David Haussler
- Center for Biomolecular Science and Engineering, University of California and Howard Hughes Medical Institute, Santa Cruz, CA 95064, USA
| | - Frank M J Jacobs
- University of Amsterdam, Swammerdam Institute for Life Sciences, 1098 XH Amsterdam, the Netherlands.
| | - Raphael Gaudin
- Inserm U1110, Université de Strasbourg, Institut de Recherche sur les Maladies Virales et Hépatiques, 67000 Strasbourg, France; Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
| | - Christopher A Walsh
- Division of Genetics and Genomics and Howard Hughes Medical Institute, Boston Children's Hospital, Departments of Pediatrics and Neurology, Harvard Medical School, Boston, MA 02115, USA.
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29
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Bekbulat F, Schmitt D, Feldmann A, Huesmann H, Eimer S, Juretschke T, Beli P, Behl C, Kern A. RAB18 Loss Interferes With Lipid Droplet Catabolism and Provokes Autophagy Network Adaptations. J Mol Biol 2019; 432:1216-1234. [PMID: 31874152 DOI: 10.1016/j.jmb.2019.12.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 12/16/2019] [Accepted: 12/16/2019] [Indexed: 12/18/2022]
Abstract
Autophagy is dependent on appropriate lipid supply for autophagosome formation. The regulation of lipid acquisition and the autophagy network response to lipid-limiting conditions are mostly elusive. Here, we show that the knockout of the RAB GTPase RAB18 interferes with lipid droplet catabolism, causing an impaired fatty acid release. The resulting reduced lipid-droplet-derived lipid availability influences autophagy and provokes adaptive modifications of the autophagy network. These adjustments include increased expression and phosphorylation of ATG2B as well as augmented formation of the ATG12-ATG5 conjugate. Moreover, ATG9A shows an enhanced phosphorylation at amino acid residues tyrosine 8 and serine 14, resulting in an increased ATG9A trafficking. Via pharmacological inhibition of Y8 phosphorylation, we demonstrate that this ATG9A modification is important to maintain basal autophagy under RAB18 knockout conditions. However, while the network adaptations are sufficient to maintain basal autophagic activity, they are incapable of ensuring autophagy induction upon starvation, which is characterized by an enhanced lipid demand. Thus, here, we define the molecular role of RAB18 in connecting lipid droplets and autophagy, emphasize the significance of lipid droplets as lipid sources for the degradative pathway, and uncover a remarkable autophagy network plasticity, including phosphorylation-dependent ATG9A activation, to compensate reduced lipid availability in order to rescue basal autophagic activity.
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Affiliation(s)
- Fazilet Bekbulat
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany
| | - Daniel Schmitt
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany
| | - Anne Feldmann
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany
| | - Heike Huesmann
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany
| | - Stefan Eimer
- Department of Structural Cell Biology, Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, Max-von-Laue-Str. 13, 60438 Frankfurt, Germany
| | - Thomas Juretschke
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany
| | - Petra Beli
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128 Mainz, Germany
| | - Christian Behl
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany.
| | - Andreas Kern
- Institute of Pathobiochemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, 55128 Mainz, Germany.
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30
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Frisbie CP, Lushnikov AY, Krasnoslobodtsev AV, Riethoven JJM, Clarke JL, Stepchenkova EI, Petrosyan A. Post-ER Stress Biogenesis of Golgi Is Governed by Giantin. Cells 2019; 8:E1631. [PMID: 31847122 PMCID: PMC6953117 DOI: 10.3390/cells8121631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/05/2019] [Accepted: 12/09/2019] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The Golgi apparatus undergoes disorganization in response to stress, but it is able to restore compact and perinuclear structure under recovery. This self-organization mechanism is significant for cellular homeostasis, but remains mostly elusive, as does the role of giantin, the largest Golgi matrix dimeric protein. METHODS In HeLa and different prostate cancer cells, we used the model of cellular stress induced by Brefeldin A (BFA). The conformational structure of giantin was assessed by proximity ligation assay and atomic force microscopy. The post-BFA distribution of Golgi resident enzymes was examined by 3D SIM high-resolution microscopy. RESULTS We detected that giantin is rather flexible than an extended coiled-coil dimer and BFA-induced Golgi disassembly was associated with giantin monomerization. A fusion of the nascent Golgi membranes after BFA washout is forced by giantin re-dimerization via disulfide bond in its luminal domain and assisted by Rab6a GTPase. GM130-GRASP65-dependent enzymes are able to reach the nascent Golgi membranes, while giantin-sensitive enzymes appeared at the Golgi after its complete recovery via direct interaction of their cytoplasmic tail with N-terminus of giantin. CONCLUSION Post-stress recovery of Golgi is conducted by giantin dimer and Golgi proteins refill membranes according to their docking affiliation rather than their intra-Golgi location.
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Affiliation(s)
- Cole P. Frisbie
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA;
| | - Alexander Y. Lushnikov
- Nanoimaging Core Facility, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA; (A.Y.L.); (A.V.K.)
| | - Alexey V. Krasnoslobodtsev
- Nanoimaging Core Facility, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA; (A.Y.L.); (A.V.K.)
- Department of Physics, University of Nebraska-Omaha, Omaha, NE 68182-0266, USA
| | - Jean-Jack M. Riethoven
- Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE 68588-0665, USA;
- The Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA;
| | - Jennifer L. Clarke
- The Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA;
- Department of Statistics, University of Nebraska-Lincoln, Lincoln, NE 68583-0963, USA
| | - Elena I. Stepchenkova
- Vavilov Institute of General Genetics, Saint-Petersburg Branch, Russian Academy of Sciences, Saint-Petersburg 199034, Russia;
- Department of Genetics, Saint-Petersburg State University, Saint-Petersburg 199034, Russia
| | - Armen Petrosyan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198-5870, USA;
- The Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE 68588-0304, USA;
- The Fred and Pamela Buffett Cancer Center, Omaha, NE 68198-5870, USA
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Gao G, Sheng Y, Yang H, Chua BT, Xu L. DFCP1 associates with lipid droplets. Cell Biol Int 2019; 43:1492-1504. [PMID: 31293035 DOI: 10.1002/cbin.11199] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 07/07/2019] [Indexed: 01/24/2023]
Abstract
Double FYVE-containing protein 1 (DFCP1) is ubiquitously expressed, participates in intracellular membrane trafficking and labels omegasomes through specific interactions with phosphatidylinositol-3-phosphate (PI3P). Previous studies showed that subcellular DFCP1 proteins display multi-organelle localization, including in the endoplasmic reticulum (ER), Golgi apparatus and mitochondria. However, its localization and function on lipid droplets (LDs) remain unclear. Here, we demonstrate that DFCP1 localizes to the LD upon oleic acid incubation. The ER-targeted domain of DFCP1 is indispensable for its LD localization, which is further enhanced by double FYVE domains. Inhibition of PI3P binding at the FYVE domain through wortmannin treatment or double mutation at C654S and C770S have no effect on DFCP1's LD localization. These show that the mechanisms for DFCP1 targeting the omegasome and LDs are different. DFCP1 deficiency in MEF cells causes an increase in LD number and reduces LD size. Interestingly, DFCP1 interacts with GTP-bound Rab18, an LD-associated protein. Taken together, our work demonstrates the dynamic localization of DFCP1 is regulated by nutritional status in response to cellular metabolism.
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Affiliation(s)
- Guangang Gao
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Yuanyuan Sheng
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, 2052 New South Wales, Sydney, Australia
| | - Boon Tin Chua
- The Institute of Metabolism and Integrative Biology, Fudan University, 200438, Shanghai, China
| | - Li Xu
- State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
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Dejgaard SY, Presley JF. Rab18 regulates lipolysis via Arf/GBF1 and adipose triglyceride lipase. Biochem Biophys Res Commun 2019; 520:526-531. [PMID: 31610914 DOI: 10.1016/j.bbrc.2019.10.069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 10/06/2019] [Indexed: 01/09/2023]
Abstract
Rab18 is a small GTPase associated with lipid droplets and other membranes. While it likely has multiple functions on lipid droplets, one proposed function is regulation of lipolysis. Previous work has concentrated on regulation of autophagy; however, in this study, we provide evidence that Rab18 plays a role upstream of the cytosolic lipolytic enzyme adipose triglyceride lipase (ATGL) and that recruitment of ATGL by Rab18 is mediated by elements of the Arf/GBF1 machinery. We find that Arf4-GFP is accumulated on the subset of lipid droplets associated with Rab18, and that this association is lost within 5 min upon treatment with 5 μg/ml of the drug brefeldin A, which targets GBF1 and other Sec7-domain containing Arf exchange factors. ATGL-GFP is also recruited to lipid droplets, but is lost more slowly after treatment with 5 μg/ml brefeldin A, with significant loss from lipid droplets after 1 h treatment, and almost complete loss from lipid droplets 4 h after brefeldin A treatment. Upon overexpression of the dominant negative GDP-locked cerulean-Rab18-S22 N, GFP-ATGL and Arf4 are lost from the surface of lipid droplets similarly to BFA treatment. This study establishes, for the first time, an essential role for Rab18 in recruiting ATGL to lipid droplets.
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Affiliation(s)
- Selma Yilmaz Dejgaard
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada; Department of Medical Biology, Near East University, Nicosia, Cyprus
| | - John F Presley
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.
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RAB18 modulates autophagy in human stellate cells. J Clin Lipidol 2019; 13:832-838. [PMID: 31563421 DOI: 10.1016/j.jacl.2019.07.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 07/06/2019] [Accepted: 07/16/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Macroautophagy (or autophagy) is a conserved degradative pathway that breaks down sequestered cytoplasmic proteins and organelles in specialized double-membrane compartments called autophagosomes that fuse with lysosomes. Several proteins orchestrate this process, specifically Rab GTPases that are master regulators of molecular trafficking. RAB18 GTPase, a known mediator of stellate cell activation, is known to modulate autophagic flux in fibroblasts. However, its role in autophagy is unexplored in hepatic stellate cells. OBJECTIVE The aim of this study was to investigate the role of RAB18 in modulating autophagy in hepatic stellate cells. METHODS Role of RAB18 was determined by genetic depletion, pharmacologic inhibition, and overexpression studies to monitor autophagy flux and proteostasis in human LX2 stellate cell line. RESULTS RAB18 knockdown increases autophagy flux and regulates proteostasis. LX2 cells stimulated with transforming growth factor-beta robustly increases expression of profibrotic genes such as COL1A1 and ACTA2 along with RAB18 and its guanine nucleotide exchange factor, RAB3GAP1. CONCLUSION The study elucidates a role for RAB18 in autophagy and regulation of proteostasis in human stellate cells. Molecular insights into this process can provide therapeutic opportunities for intervention in liver fibrosis.
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Gillingham AK, Bertram J, Begum F, Munro S. In vivo identification of GTPase interactors by mitochondrial relocalization and proximity biotinylation. eLife 2019; 8:45916. [PMID: 31294692 PMCID: PMC6639074 DOI: 10.7554/elife.45916] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Accepted: 07/10/2019] [Indexed: 12/11/2022] Open
Abstract
The GTPases of the Ras superfamily regulate cell growth, membrane traffic and the cytoskeleton, and a wide range of diseases are caused by mutations in particular members. They function as switchable landmarks with the active GTP-bound form recruiting to the membrane a specific set of effector proteins. The GTPases are precisely controlled by regulators that promote acquisition of GTP (GEFs) or its hydrolysis to GDP (GAPs). We report here MitoID, a method for identifying effectors and regulators by performing in vivo proximity biotinylation with mitochondrially-localized forms of the GTPases. Applying this to 11 human Rab GTPases identified many known effectors and GAPs, as well as putative novel effectors, with examples of the latter validated for Rab2, Rab5, Rab9 and Rab11. MitoID can also efficiently identify effectors and GAPs of Rho and Ras family GTPases such as Cdc42, RhoA, Rheb, and N-Ras, and can identify GEFs by use of GDP-bound forms.
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Affiliation(s)
| | - Jessie Bertram
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Farida Begum
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
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35
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Estrogen enhances human osteoblast survival and function via promotion of autophagy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:1498-1507. [PMID: 31255720 DOI: 10.1016/j.bbamcr.2019.06.014] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/05/2019] [Accepted: 06/26/2019] [Indexed: 12/12/2022]
Abstract
Estrogen increases bone formation by promoting mineralization and prolonging the lifespan of osteoblasts. To understand the underlying molecular mechanism/s, we identified estrogen-regulated proteins at different stages of human osteoblast differentiation using differential proteomics approach. Among the identified proteins, we observed that estrogen upregulated RAB3GAP1 on day 1 and 5 of differentiation. RAB3GAP1 is critically involved in the process of autophagy, a eukaryotic degradative pathway essential for cell survival. We, therefore, investigated the effect of estrogen on autophagy in differentiating human osteoblasts and their precursors, the mesenchymal stem cells (MSCs). MSCs exhibited high autophagic flux which declined during osteoblast differentiation, resulting in high basal apoptosis in osteoblasts. Estrogen reduced apoptosis in differentiating osteoblasts by promoting autophagy, thus contributing towards their longer lifespan. Further, MSCs were resistant against starvation-induced apoptosis, whereas, differentiating osteoblasts showed significant susceptibility towards it. Estrogen, in addition to promoting mineralization, protected differentiating osteoblasts from starvation-induced apoptosis by increasing autophagic flux. Autophagic flux in RAB3GAP1 knockdown osteoblasts appeared diminished, and showed increased apoptosis even in nutrient-rich conditions, and exhibited significantly impaired mineralization. However, irrespective of the presence of estrogen, starvation further enhanced apoptosis in these cells. Furthermore, estrogen failed to promote mineralization in these osteoblasts. Our study illustrates that autophagy is essential for human osteoblast survival and mineralization, and osteoblasts are susceptible to apoptosis due to reduced autophagy during differentiation. Estrogen, via upregulation of RAB3GAP1, promotes autophagy in osteoblasts during differentiation thereby increasing their survival and mineralization capacity. Our study demonstrates the positive role of autophagy in bone homeostasis.
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36
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A germline mutation in Rab43 gene identified from a cancer family predisposes to a hereditary liver-colon cancer syndrome. BMC Cancer 2019; 19:613. [PMID: 31226964 PMCID: PMC6588942 DOI: 10.1186/s12885-019-5845-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/16/2019] [Indexed: 12/18/2022] Open
Abstract
Background Hereditary cancer syndromes have inherited germline mutations which predispose to benign and malignant tumors. Understanding of the molecular causes in hereditary cancer syndromes has advanced cancer treatment and prevention. However, the causal genes of many hereditary cancer syndromes remain unknown due to their rare frequency of mutation. Methods A large Chinese family with a history of hereditary liver-colon cancer syndrome was studied. The genomic DNA was extracted from the blood samples of involved family members, whole-exome sequencing was performed to identify genetic variants. Functional validation of a candidate variant was carried out using gene expression, gene knockout and immunohistochemistry. Results The whole-exome of the proband diagnosed with colon cancer was sequenced in comparison with his mother. A total of 13 SNVs and 16 InDels were identified. Among these variants, we focused on a mutation of Rab43 gene, a GTPase family member involving in protein trafficking, for further validation. Sanger DNA sequencing confirmed a mutation (c: 128810106C > T, p: A158T) occurred in one allele of Rab43 gene from the proband, that heterozygous mutation also was verified in the genome of the proband’s deceased father with liver cancer, but not in his healthy mother and sister. Ectopic expression of the Rab43 A158T mutant in Huh7 cells led to more enhanced cell growth, proliferation and migration compared to the expression of wild type Rab43. Conversely, knockout of Rab43 in HepG2 cells resulted in slow cell growth and multiple nuclei formation and impaired activation of Akt. Finally, a positive correlation between the expression levels of Rab43 protein and cancer development in that family was confirmed. Conclusions A germline mutation of Rab43 gene is identified to be associated with the onset of a familial liver-colon cancer syndrome. Our finding points to a potential role of protein trafficking in the tumorigenesis of the familial cancer syndrome, and helps the genetic counseling to the affected family members. Electronic supplementary material The online version of this article (10.1186/s12885-019-5845-4) contains supplementary material, which is available to authorized users.
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37
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A Premature Stop Codon in RAF1 Is the Priority Candidate Causative Mutation of the Inherited Chicken Wingless-2 Developmental Syndrome. Genes (Basel) 2019; 10:genes10050353. [PMID: 31075853 PMCID: PMC6562611 DOI: 10.3390/genes10050353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/23/2019] [Accepted: 04/26/2019] [Indexed: 11/17/2022] Open
Abstract
The chicken wingless-2 (wg-2) mutation is inherited in an autosomal recessive fashion, and the resulting phenotype in mutant (wg-2/wg-2) individuals is a developmental syndrome characterized by absent wings, truncated legs, craniofacial as well as skin and feather defects, and kidney malformations. Mapping and genotyping established that the mutation resides within 227 kilobases (kb) of chromosome 12 in a wg-2 congenic inbred line. A capture array was designed to target and sequence the candidate region along with flanking DNA in 24 birds from the line. Many point mutations and insertions or deletions were identified, and analysis of the linked variants indicated a point mutation predicted to cause a premature stop codon in the RAF1 gene. Expression studies were conducted inclusive of all genes in the candidate region. Interestingly, RAF1 transcription was elevated, yet the protein was absent in the mutants relative to normal individuals. RAF1 encodes a protein integral to the Ras/Raf/MAPK signaling pathway controlling cellular proliferation, and notably, human RASopathies are developmental syndromes caused by germline mutations in genes of this pathway. Our work indicates RAF1 as the priority candidate causative gene for wg-2 and provides a new animal model to study an important signaling pathway implicated in limb development, as well as RASopathies.
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38
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Parakh S, Perri ER, Jagaraj CJ, Ragagnin AMG, Atkin JD. Rab-dependent cellular trafficking and amyotrophic lateral sclerosis. Crit Rev Biochem Mol Biol 2019; 53:623-651. [PMID: 30741580 DOI: 10.1080/10409238.2018.1553926] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Rab GTPases are becoming increasingly implicated in neurodegenerative disorders, although their role in amyotrophic lateral sclerosis (ALS) has been somewhat overlooked. However, dysfunction of intracellular transport is gaining increasing attention as a pathogenic mechanism in ALS. Many previous studies have focused axonal trafficking, and the extreme length of axons in motor neurons may contribute to their unique susceptibility in this disorder. In contrast, the role of transport defects within the cell body has been relatively neglected. Similarly, whilst Rab GTPases control all intracellular membrane trafficking events, their role in ALS is poorly understood. Emerging evidence now highlights this family of proteins in ALS, particularly the discovery that C9orf72 functions in intra transport in conjunction with several Rab GTPases. Here, we summarize recent updates on cellular transport defects in ALS, with a focus on Rab GTPases and how their dysfunction may specifically target neurons and contribute to pathophysiology. We discuss the molecular mechanisms associated with dysfunction of Rab proteins in ALS. Finally, we also discuss dysfunction in other modes of transport recently implicated in ALS, including nucleocytoplasmic transport and the ER-mitochondrial contact regions (MAM compartment), and speculate whether these may also involve Rab GTPases.
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Affiliation(s)
- S Parakh
- a Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Centre for MND Research , Macquarie University , Sydney , Australia.,b Department of Biochemistry and Genetics , La Trobe Institute for Molecular Science, La Trobe University , Melbourne , Australia
| | - E R Perri
- a Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Centre for MND Research , Macquarie University , Sydney , Australia.,b Department of Biochemistry and Genetics , La Trobe Institute for Molecular Science, La Trobe University , Melbourne , Australia
| | - C J Jagaraj
- a Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Centre for MND Research , Macquarie University , Sydney , Australia
| | - A M G Ragagnin
- a Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Centre for MND Research , Macquarie University , Sydney , Australia
| | - J D Atkin
- a Faculty of Medicine and Health Sciences, Department of Biomedical Sciences, Centre for MND Research , Macquarie University , Sydney , Australia.,b Department of Biochemistry and Genetics , La Trobe Institute for Molecular Science, La Trobe University , Melbourne , Australia
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39
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Dejgaard SY, Presley JF. Rab18: new insights into the function of an essential protein. Cell Mol Life Sci 2019; 76:1935-1945. [PMID: 30830238 PMCID: PMC11105521 DOI: 10.1007/s00018-019-03050-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 12/14/2022]
Abstract
Rab18 is one of the small number of conserved Rab proteins which have been traced to the last eukaryotic common ancestor. It is found in organisms ranging from humans to trypanosomes, and localizes to multiple organelles, including most notably endoplasmic reticulum and lipid droplets. In humans, absence of Rab18 leads to a severe illness known as Warburg-Micro syndrome. Despite this evidence that Rab18 is essential, its role in cells remains mysterious. However, recent studies identifying effectors and interactors of Rab18, are now shedding light on its mechanism of action, suggesting functions related to organelle tethering and to autophagy. In this review, we examine the variety of roles proposed for Rab18 with a focus on new evidence giving insights into the molecular mechanisms it utilizes. Based on this summary of our current understanding, we identify priority areas for further research.
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Affiliation(s)
- Selma Yilmaz Dejgaard
- Department of Medical Biology, Near East University, Nicosia, Cyprus
- Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montreal, QC, H3A 0C7, Canada
| | - John F Presley
- Department of Anatomy and Cell Biology, McGill University, 3640 University Street, Montreal, QC, H3A 0C7, Canada.
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40
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Rasika S, Passemard S, Verloes A, Gressens P, El Ghouzzi V. Golgipathies in Neurodevelopment: A New View of Old Defects. Dev Neurosci 2019; 40:396-416. [PMID: 30878996 DOI: 10.1159/000497035] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 01/16/2019] [Indexed: 11/19/2022] Open
Abstract
The Golgi apparatus (GA) is involved in a whole spectrum of activities, from lipid biosynthesis and membrane secretion to the posttranslational processing and trafficking of most proteins, the control of mitosis, cell polarity, migration and morphogenesis, and diverse processes such as apoptosis, autophagy, and the stress response. In keeping with its versatility, mutations in GA proteins lead to a number of different disorders, including syndromes with multisystem involvement. Intriguingly, however, > 40% of the GA-related genes known to be associated with disease affect the central or peripheral nervous system, highlighting the critical importance of the GA for neural function. We have previously proposed the term "Golgipathies" in relation to a group of disorders in which mutations in GA proteins or their molecular partners lead to consequences for brain development, in particular postnatal-onset microcephaly (POM), white-matter defects, and intellectual disability (ID). Here, taking into account the broader role of the GA in the nervous system, we refine and enlarge this emerging concept to include other disorders whose symptoms may be indicative of altered neurodevelopmental processes, from neurogenesis to neuronal migration and the secretory function critical for the maturation of postmitotic neurons and myelination.
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Affiliation(s)
- Sowmyalakshmi Rasika
- NeuroDiderot, INSERM UMR1141, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,AP HP, Hôpital Robert Debré, UF de Génétique Clinique, Paris, France
| | - Sandrine Passemard
- NeuroDiderot, INSERM UMR1141, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,AP HP, Hôpital Robert Debré, UF de Génétique Clinique, Paris, France
| | - Alain Verloes
- NeuroDiderot, INSERM UMR1141, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,AP HP, Hôpital Robert Debré, UF de Génétique Clinique, Paris, France
| | - Pierre Gressens
- NeuroDiderot, INSERM UMR1141, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.,Centre for the Developing Brain, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' Hospital, London, United Kingdom
| | - Vincent El Ghouzzi
- NeuroDiderot, INSERM UMR1141, Université Paris Diderot, Sorbonne Paris Cité, Paris, France,
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Koparir A, Karatas OF, Yilmaz SS, Suer I, Ozer B, Yuceturk B, Ozen M. Revealing the functions of novel mutations in RAB3GAP1
in Martsolf and Warburg micro syndromes. Am J Med Genet A 2019; 179:579-587. [DOI: 10.1002/ajmg.a.61065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/17/2019] [Accepted: 01/17/2019] [Indexed: 12/30/2022]
Affiliation(s)
- Asuman Koparir
- Department of Internal Medicine, Division of Medical Genetics; Istanbul University; Istanbul Turkey
| | - Omer Faruk Karatas
- Molecular Biology and Genetics Department; Erzurum Technical University; Erzurum Turkey
| | - Seda Salman Yilmaz
- Department of Medical Genetics; Istanbul University, Cerrahpasa Medical School; Istanbul Turkey
| | - Ilknur Suer
- Department of Internal Medicine, Division of Medical Genetics; Istanbul University; Istanbul Turkey
| | - Bugra Ozer
- Advanced Genomics and Bioinformatics Research Center; The Scientific and Technological Research Council of Turkey (TUBITAK-BILGEM); Kocaeli Turkey
| | - Betul Yuceturk
- Advanced Genomics and Bioinformatics Research Center; The Scientific and Technological Research Council of Turkey (TUBITAK-BILGEM); Kocaeli Turkey
| | - Mustafa Ozen
- Department of Medical Genetics; Istanbul University, Cerrahpasa Medical School; Istanbul Turkey
- Department of Pathology and Immunology; Baylor College of Medicine; Houston Texas
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Nian FS, Li LL, Cheng CY, Wu PC, Lin YT, Tang CY, Ren BS, Tai CY, Fann MJ, Kao LS, Hong CJ, Tsai JW. Rab18 Collaborates with Rab7 to Modulate Lysosomal and Autophagy Activities in the Nervous System: an Overlapping Mechanism for Warburg Micro Syndrome and Charcot-Marie-Tooth Neuropathy Type 2B. Mol Neurobiol 2019; 56:6095-6105. [PMID: 30721447 DOI: 10.1007/s12035-019-1471-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 01/10/2019] [Indexed: 01/24/2023]
Abstract
Mutations in RAB18, a member of small G protein, cause Warburg micro syndrome (WARBM), whose clinical features include vision impairment, postnatal microcephaly, and lower limb spasticity. Previously, our Rab18-/- mice exhibited hind limb weakness and spasticity as well as signs of axonal degeneration in the spinal cord and lumbar spinal nerves. However, the cellular and molecular function of RAB18 and its roles in the pathogenesis of WARBM are still not fully understood. Using immunofluorescence staining and expression of Rab18 and organelle markers, we find that Rab18 associates with lysosomes and actively traffics along neurites in cultured neurons. Interestingly, Rab18-/- neurons exhibit impaired lysosomal transport. Using autophagosome marker LC3-II, we show that Rab18 dysfunction leads to aberrant autophagy activities in neurons. Electron microscopy further reveals accumulation of lipofuscin-like granules in the dorsal root ganglion of Rab18-/- mice. Surprisingly, Rab18 colocalizes, cofractionates, and coprecipitates with the lysosomal regulator Rab7, mutations of which cause Charcot-Marie-Tooth (CMT) neuropathy type 2B. Moreover, Rab7 is upregulated in Rab18-deficient neurons, suggesting a compensatory effect. Together, our results suggest that the functions of RAB18 and RAB7 in lysosomal and autophagic activities may constitute an overlapping mechanism underlying WARBM and CMT pathogenesis in the nervous system.
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Affiliation(s)
- Fang-Shin Nian
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan.,Program in Molecular Medicine, National Yang-Ming University and Academia Sinica, Taipei, Taiwan
| | - Lei-Li Li
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Chih-Ya Cheng
- Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Pei-Chun Wu
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - You-Tai Lin
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Cheng-Yung Tang
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Bo-Shiun Ren
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan
| | - Chin-Yin Tai
- Institute of Molecular Biology, Academia Sinica, Nankang, Taipei, Taiwan
| | - Ming-Ji Fann
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Lung-Sen Kao
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan.,Brain Research Center, National Yang-Ming University, Taipei, Taiwan
| | - Chen-Jee Hong
- Brain Research Center, National Yang-Ming University, Taipei, Taiwan.,Division of Psychiatry, School of Medicine, National Yang-Ming University, Taipei, Taiwan.,Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Jin-Wu Tsai
- Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan. .,Brain Research Center, National Yang-Ming University, Taipei, Taiwan. .,Biopotonics and Molecular Imaging Research Center, National Yang-Ming University, Taipei, Taiwan.
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Rivero-Ríos P, Romo-Lozano M, Madero-Pérez J, Thomas AP, Biosa A, Greggio E, Hilfiker S. The G2019S variant of leucine-rich repeat kinase 2 (LRRK2) alters endolysosomal trafficking by impairing the function of the GTPase RAB8A. J Biol Chem 2019; 294:4738-4758. [PMID: 30709905 PMCID: PMC6442034 DOI: 10.1074/jbc.ra118.005008] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 01/30/2019] [Indexed: 12/25/2022] Open
Abstract
Mutations in the gene encoding for leucine-rich repeat kinase 2 (LRRK2) are a common cause of hereditary Parkinson's disease. LRRK2 regulates various intracellular vesicular trafficking pathways, including endolysosomal degradative events such as epidermal growth factor receptor (EGFR) degradation. Recent studies have revealed that a subset of RAB proteins involved in secretory and endocytic recycling are LRRK2 kinase substrates in vivo. However, the effects of LRRK2-mediated phosphorylation of these substrates on membrane trafficking remain unknown. Here, using an array of immunofluorescence and pulldown assays, we report that expression of active or phosphodeficient RAB8A variants rescues the G2019S LRRK2–mediated effects on endolysosomal membrane trafficking. Similarly, up-regulation of the RAB11–Rabin8–RAB8A cascade, which activates RAB8A, also reverted these trafficking deficits. Loss of RAB8A mimicked the effects of G2019S LRRK2 on endolysosomal trafficking and decreased RAB7A activity. Expression of pathogenic G2019S LRRK2 or loss of RAB8A interfered with EGFR degradation by causing its accumulation in a RAB4-positive endocytic compartment, which was accompanied by a deficit in EGFR recycling and was rescued upon expression of active RAB7A. Dominant-negative RAB7A expression resulted in similar deficits in EGF degradation, accumulation in a RAB4 compartment, and deficits in EGFR recycling, which were all rescued upon expression of active RAB8A. Taken together, these findings suggest that, by impairing RAB8A function, pathogenic G2019S LRRK2 deregulates endolysosomal transport and endocytic recycling events.
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Affiliation(s)
- Pilar Rivero-Ríos
- From the Institute of Parasitology and Biomedicine "López-Neyra," Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain
| | - María Romo-Lozano
- From the Institute of Parasitology and Biomedicine "López-Neyra," Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain
| | - Jesús Madero-Pérez
- From the Institute of Parasitology and Biomedicine "López-Neyra," Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain
| | - Andrew P Thomas
- the Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103, and
| | - Alice Biosa
- the Department of Biology, University of Padova, Padova 35121, Italy
| | - Elisa Greggio
- the Department of Biology, University of Padova, Padova 35121, Italy
| | - Sabine Hilfiker
- From the Institute of Parasitology and Biomedicine "López-Neyra," Consejo Superior de Investigaciones Científicas (CSIC), Avda del Conocimiento s/n, 18016 Granada, Spain,
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Abstract
The Golgi apparatus is a central intracellular membrane-bound organelle with key functions in trafficking, processing, and sorting of newly synthesized membrane and secretory proteins and lipids. To best perform these functions, Golgi membranes form a unique stacked structure. The Golgi structure is dynamic but tightly regulated; it undergoes rapid disassembly and reassembly during the cell cycle of mammalian cells and is disrupted under certain stress and pathological conditions. In the past decade, significant amount of effort has been made to reveal the molecular mechanisms that regulate the Golgi membrane architecture and function. Here we review the major discoveries in the mechanisms of Golgi structure formation, regulation, and alteration in relation to its functions in physiological and pathological conditions to further our understanding of Golgi structure and function in health and diseases.
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Affiliation(s)
- Jie Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Erpan Ahat
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI, USA.
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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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Elgner F, Hildt E, Bender D. Relevance of Rab Proteins for the Life Cycle of Hepatitis C Virus. Front Cell Dev Biol 2018; 6:166. [PMID: 30564577 PMCID: PMC6288913 DOI: 10.3389/fcell.2018.00166] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 11/20/2018] [Indexed: 12/18/2022] Open
Abstract
Although potent direct-acting antiviral drugs for the treatment of chronic hepatitis C virus (HCV) infection are licensed, there are more than 70 million individuals suffering from chronic HCV infection. In light of the limited access to these drugs, high costs, and a lot of undiagnosed cases, it is expected that the number of HCV cases will not decrease worldwide in the next years. Therefore, and due to the paradigmatic character of HCV for deciphering the crosstalk between viral pathogens and the host cell, characterization of HCV life cycle remains a challenge. HCV belongs to the family of Flaviviridae. As an enveloped virus HCV life cycle depends in many steps on intracellular trafficking. Rab GTPases, a large family of small GTPases, play a central role in intracellular trafficking processes controlling fusion, uncoating, vesicle budding, motility by recruiting specific effector proteins. This review describes the relevance of various Rab proteins for the different steps of the HCV life cycle.
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Affiliation(s)
- Fabian Elgner
- Department of Virology, Paul-Ehrlich-Institut, Langen, Germany
| | - Eberhard Hildt
- Department of Virology, Paul-Ehrlich-Institut, Langen, Germany
| | - Daniela Bender
- Department of Virology, Paul-Ehrlich-Institut, Langen, Germany
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Wei F, Duan Y. Crosstalk between Autophagy and Nanomaterials: Internalization, Activation, Termination. ACTA ACUST UNITED AC 2018; 3:e1800259. [PMID: 32627344 DOI: 10.1002/adbi.201800259] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/02/2018] [Indexed: 12/12/2022]
Abstract
Nanomaterials (NMs) are comprehensively applied in biomedicine due to their unique physical and chemical properties. Autophagy, as an evolutionarily conserved cellular quality control process, is closely associated with the effect of NMs on cells. In this review, the recent advances in NM-induced/inhibited autophagy (NM-phagy) are summarized, with an aim to present a comprehensive description of the mechanisms of NM-phagy from the perspective of internalization, activation, and termination, thereby bridging autophagy and nanomaterials. Several possible mechanisms are extensively reviewed including the endocytosis pathway of NMs and the related cross components (clathrin and adaptor protein 2 (AP-2), adenosine diphosphate (ADP)-ribosylation factor 6 (Arf6), Rab, UV radiation resistance associated gene (UVRAG)), three main stress mechanisms (oxidative stress, damaged organelles stress, and toxicity stress), and several signal pathway-related molecules. The mechanistic insight is beneficial to understand the autophagic response to NMs or NMs' regulation of autophagy. The challenges currently encountered and research trend in the field of NM-phagy are also highlighted. It is hoped that the NM-phagy discussion in this review with the focus on the mechanistic aspects may serve as a guideline for future research in this field.
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Affiliation(s)
- Fujing Wei
- Research Center of Analytical Instrumentation, Key Laboratory of Bio-resource and Eco-enviroment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, P. R. China
| | - Yixiang Duan
- Research Center of Analytical Instrumentation, Key Laboratory of Bio-resource and Eco-enviroment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, Sichuan, P. R. China
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Abstract
Fruit ripening is a complex developmental process that involves the synthesis and modification of the cell wall leading up to the formation of an edible fruit. During the period of fruit ripening, new cell wall polymers and enzymes are synthesized and trafficked to the apoplast. Vesicle trafficking has been shown to play a key role in facilitating the synthesis and modification of cell walls in fruits. Through reverse genetics and gene expression studies, the importance of Rab guanosine triphosphatases (GTPases) as integral regulators of vesicle trafficking to the cell wall has been revealed. It has been a decade since a rich literature on the involvement of Rab GTPase in ripening was published. Therefore, this review sets out to summarize the progress in studies on the pivotal roles of Rab GTPases in fruit development and sheds light on new approaches that could be adopted in the fields of postharvest biology and fruit-ripening research.
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Affiliation(s)
- Tamunonengiyeofori Lawson
- a School of Biosciences, Faculty of Science , The University of Nottingham, Malaysia Campus , Semenyih , Selangor , Malaysia.,b Division of Plant and Crop Sciences, School of Biosciences , University of Nottingham , Sutton Bonington Campus, Loughborough , Leicestershire , UK.,c Crops for the Future (CFF) , Semenyih , Malaysia
| | - Sean Mayes
- b Division of Plant and Crop Sciences, School of Biosciences , University of Nottingham , Sutton Bonington Campus, Loughborough , Leicestershire , UK.,c Crops for the Future (CFF) , Semenyih , Malaysia
| | - Grantley W Lycett
- b Division of Plant and Crop Sciences, School of Biosciences , University of Nottingham , Sutton Bonington Campus, Loughborough , Leicestershire , UK
| | - Chiew Foan Chin
- a School of Biosciences, Faculty of Science , The University of Nottingham, Malaysia Campus , Semenyih , Selangor , Malaysia
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Harris JL, Dave K, Gorman J, Khanna KK. The breast cancer antigen 5T4 interacts with Rab11, and is a target and regulator of Rab11 mediated trafficking. Int J Biochem Cell Biol 2018; 99:28-37. [DOI: 10.1016/j.biocel.2018.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/07/2018] [Accepted: 03/08/2018] [Indexed: 01/19/2023]
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50
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Chua CEL, Tang BL. Rab 10-a traffic controller in multiple cellular pathways and locations. J Cell Physiol 2018; 233:6483-6494. [PMID: 29377137 DOI: 10.1002/jcp.26503] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 01/24/2018] [Indexed: 12/29/2022]
Abstract
Rab GTPases are key regulators of eukaryotic membrane traffic, and their functions and activities are limited to particular intracellular transport steps and their membrane localization is by and large restricted. Some Rabs do participate in more than one transport steps, but broadly speaking, there is a clear demarcation between exocytic and endocytic Rabs. One Rab protein, Rab10, however, appears to be anomalous in this regard and has a diverse array of functions and subcellular localizations. Rab10 has been implicated in a myriad of activities ranging from polarized exocytosis and endosomal sorting in polarized cells, insulin-dependent Glut4 transport in adipocytes, axonal growth in neurons, and endo-phagocytic processes in macrophages. It's reported subcellular localizations include the endoplasmic reticulum (ER), Golgi/TGN, the endosomes/phagosomes and the primary cilia. In this review, we summarize and discuss the multitude of known roles of Rab10 in cellular membrane transport and the molecular players and mechanisms associated with these roles.
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Affiliation(s)
- Christelle En Lin Chua
- Singapore Nuclear Research and Safety Initiative, National University of Singapore, Singapore
| | - Bor L Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore
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