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Shvarev D, König C, Susan N, Langemeyer L, Walter S, Perz A, Fröhlich F, Ungermann C, Moeller A. Structure of the endosomal CORVET tethering complex. Nat Commun 2024; 15:5227. [PMID: 38898033 PMCID: PMC11187117 DOI: 10.1038/s41467-024-49137-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 05/24/2024] [Indexed: 06/21/2024] Open
Abstract
Cells depend on their endolysosomal system for nutrient uptake and downregulation of plasma membrane proteins. These processes rely on endosomal maturation, which requires multiple membrane fusion steps. Early endosome fusion is promoted by the Rab5 GTPase and its effector, the hexameric CORVET tethering complex, which is homologous to the lysosomal HOPS. How these related complexes recognize their specific target membranes remains entirely elusive. Here, we solve the structure of CORVET by cryo-electron microscopy and revealed its minimal requirements for membrane tethering. As expected, the core of CORVET and HOPS resembles each other. However, the function-defining subunits show marked structural differences. Notably, we discover that unlike HOPS, CORVET depends not only on Rab5 but also on phosphatidylinositol-3-phosphate (PI3P) and membrane lipid packing defects for tethering, implying that an organelle-specific membrane code enables fusion. Our data suggest that both shape and membrane interactions of CORVET and HOPS are conserved in metazoans, thus providing a paradigm how tethering complexes function.
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Affiliation(s)
- Dmitry Shvarev
- Department of Biology/Chemistry, Structural Biology Section, Osnabrück University, 49076, Osnabrück, Germany
| | - Caroline König
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, 49076, Osnabrück, Germany
| | - Nicole Susan
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, 49076, Osnabrück, Germany
| | - Lars Langemeyer
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, 49076, Osnabrück, Germany
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, 49076, Osnabrück, Germany
| | - Stefan Walter
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, 49076, Osnabrück, Germany
| | - Angela Perz
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, 49076, Osnabrück, Germany
| | - Florian Fröhlich
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, 49076, Osnabrück, Germany
- Department of Biology/Chemistry, Bioanalytical Chemistry Section, Osnabrück University, 49076, Osnabrück, Germany
| | - Christian Ungermann
- Department of Biology/Chemistry, Biochemistry Section, Osnabrück University, 49076, Osnabrück, Germany.
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, 49076, Osnabrück, Germany.
| | - Arne Moeller
- Department of Biology/Chemistry, Structural Biology Section, Osnabrück University, 49076, Osnabrück, Germany.
- Center of Cellular Nanoanalytics Osnabrück (CellNanOs), Osnabrück University, 49076, Osnabrück, Germany.
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Ying R, Li C, Li H, Zou J, Hu M, Hong Q, Shen Y, Hou L, Cheng H, Zhou R. RPGR is a guanine nucleotide exchange factor for the small GTPase RAB37 required for retinal function via autophagy regulation. Cell Rep 2024; 43:114010. [PMID: 38536817 DOI: 10.1016/j.celrep.2024.114010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 01/28/2024] [Accepted: 03/13/2024] [Indexed: 04/28/2024] Open
Abstract
Although the small GTPase RAB37 acts as an organizer of autophagosome biogenesis, the upstream regulatory mechanism of autophagy via guanosine diphosphate (GDP)-guanosine triphosphate (GTP) exchange in maintaining retinal function has not been determined. We found that retinitis pigmentosa GTPase regulator (RPGR) is a guanine nucleotide exchange factor that activates RAB37 by accelerating GDP-to-GTP exchange. RPGR directly interacts with RAB37 via the RPGR-RCC1-like domain to promote autophagy through stimulating exchange. Rpgr knockout (KO) in mice leads to photoreceptor degeneration owing to autophagy impairment in the retina. Notably, the retinopathy phenotypes of Rpgr KO retinas are rescued by the adeno-associated virus-mediated transfer of pre-trans-splicing molecules, which produce normal Rpgr mRNAs via trans-splicing in the Rpgr KO retinas. This rescue upregulates autophagy through the re-expression of RPGR in KO retinas to accelerate GDP-to-GTP exchange; thus, retinal homeostasis reverts to normal. Taken together, these findings provide an important missing link for coordinating RAB37 GDP-GTP exchange via the RPGR and retinal homeostasis by autophagy regulation.
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Affiliation(s)
- Ruhong Ying
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Cong Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Huirong Li
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou 325003, China
| | - Juan Zou
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Mengxin Hu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Qiang Hong
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Yin Shen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China
| | - Ling Hou
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou 325003, China.
| | - Hanhua Cheng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China.
| | - Rongjia Zhou
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan 430072, China.
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Yang N, Li M, Qin S, Duan N, Li X, Zhou Y, Wang M, Jin Y, Wu W, Cheng Z. Ehrlichia chaffeensis Etf-3 Induces Host RAB15 Upregulation for Bacterial Intracellular Growth. Int J Mol Sci 2024; 25:2551. [PMID: 38473798 DOI: 10.3390/ijms25052551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024] Open
Abstract
Ehrlichia chaffeensis infects human monocytes or macrophages and causes human monocytic ehrlichiosis (HME), an emerging life-threatening zoonosis. After internalization, E. chaffeensis resides in membrane-bound inclusions, E. chaffeensis-containing vesicles (ECVs), which have early endosome-like characteristics and fuse with early autophagosomes but not lysosomes, to evade host innate immune microbicidal mechanisms and obtain nutrients for bacterial intracellular growth. The mechanisms exploited by E. chaffeensis to modulate intracellular vesicle trafficking in host cells have not been comprehensively studied. Here, we demonstrate that E. chaffeensis type IV secretion system (T4SS) effector Etf-3 induces RAB15 upregulation in host cells and that RAB15, which is localized on ECVs, inhibits ECV fusion with lysosomes and induces autophagy. We found that E. chaffeensis infection upregulated RAB15 expression using qRT-PCR, and RAB15 was colocalized with E. chaffeensis using confocal microscopy. Silence of RAB15 using siRNA enhanced ECV maturation to late endosomes and fusion with lysosomes, as well as inhibited host cell autophagy. Overexpression of Etf-3 in host cells specifically induced RAB15 upregulation and autophagy. Our findings deepen the understanding of E. chaffeensis pathogenesis and adaptation in hosts as well as the function of RAB15 and facilitate the development of new therapeutics for HME.
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Affiliation(s)
- Nan Yang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Meifang Li
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Shanhua Qin
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Nan Duan
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xiaoxiao Li
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yuhong Zhou
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Mengyao Wang
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Yongxin Jin
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Weihui Wu
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Zhihui Cheng
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Nankai University, Tianjin 300071, China
- Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China
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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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Wang L, Zhang X, Zhang Z, Qin Q, Wang S. Rab32, a novel Rab small GTPase from orange-spotted grouper, Epinephelus coioides involved in SGIV infection. FISH & SHELLFISH IMMUNOLOGY 2023; 143:109229. [PMID: 37972745 DOI: 10.1016/j.fsi.2023.109229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 11/08/2023] [Accepted: 11/11/2023] [Indexed: 11/19/2023]
Abstract
Rab32 is a member of the Rab GTPase family that is involved in membrane trafficking and immune response, which are crucial for controlling pathogen infection. However, the role of Rab32 in virus infection is not well understood. In this study, we focused on the regulation of Rab32 on virus infection and the host immunity in orange-spotted grouper, Epinephelus coioides. EcRab32 encoded a 213-amino acid polypeptide, which shared a high sequence identity with other Rab32 proteins from fishes to mammals. In healthy orange-spotted grouper, the mRNA of EcRab32 was expressed in all the detected tissues, with the more expression levels in the head kidney, liver and gill. Upon SGIV infection, the expression of EcRab32 was significantly up-regulated in vitro, indicating its potential role in viral infection. EcRab32 was observed to be distributed in the cytoplasm as punctate and vesicle-like structures. EcRab32 overexpression was found to notably inhibit SGIV infection, while the interruption of EcRab32 significantly promoted SGIV infection. In addition, using single particle imaging analysis, we found that EcRab32 overexpression prominently reduced the attachment and internalization of SGIV particles. Furthermore, the results demonstrated that EcRab32 played a positive role in regulating the interferon immune and inflammatory responses. Taken together, these findings indicated that EcRab32 influenced SGIV infection by regulating the host immune response, providing an overall understanding of the interplay between the Rab32 and innate immunity.
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Affiliation(s)
- Liqun Wang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Henry Fok School of Biology and Agriculture, Shaoguan University, Shaoguan, 512005, China
| | - Xinyue Zhang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Zihan Zhang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China
| | - Qiwei Qin
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, 511464, China.
| | - Shaowen Wang
- College of Marine Sciences, South China Agricultural University, Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, 510642, China; Nansha-South China Agricultural University Fishery Research Institute, Guangzhou, 511464, China.
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