1
|
Wang D, Ye Z, Wei W, Yu J, Huang L, Zhang H, Yue J. Capping protein regulates endosomal trafficking by controlling F-actin density around endocytic vesicles and recruiting RAB5 effectors. eLife 2021; 10:65910. [PMID: 34796874 PMCID: PMC8654373 DOI: 10.7554/elife.65910] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 11/18/2021] [Indexed: 12/30/2022] Open
Abstract
Actin filaments (F-actin) have been implicated in various steps of endosomal trafficking, and the length of F-actin is controlled by actin capping proteins, such as CapZ, which is a stable heterodimeric protein complex consisting of α and β subunits. However, the role of these capping proteins in endosomal trafficking remains elusive. Here, we found that CapZ docks to endocytic vesicles via its C-terminal actin-binding motif. CapZ knockout significantly increases the F-actin density around immature early endosomes, and this impedes fusion between these vesicles, manifested by the accumulation of small endocytic vesicles in CapZ-knockout cells. CapZ also recruits several RAB5 effectors, such as Rabaptin-5 and Rabex-5, to RAB5-positive early endosomes via its N-terminal domain, and this further activates RAB5. Collectively, our results indicate that CapZ regulates endosomal trafficking by controlling actin density around early endosomes and recruiting RAB5 effectors.
Collapse
Affiliation(s)
- Dawei Wang
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China.,Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Zuodong Ye
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China.,Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Wenjie Wei
- Core Research Facilities, Southern University of Science and Technology, Shenzhen, China
| | - Jingting Yu
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| | - Lihong Huang
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China.,Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China
| | - Hongmin Zhang
- Department of Biology, Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research and Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, China
| | - Jianbo Yue
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China.,Department of Biomedical Sciences, City University of Hong Kong, Hong Kong, China.,City University of Hong Kong Chengdu Research Institute, Chengdu, China
| |
Collapse
|
2
|
Parkinson G, Roboti P, Zhang L, Taylor S, Woodman P. His domain protein tyrosine phosphatase and Rabaptin-5 couple endo-lysosomal sorting of EGFR with endosomal maturation. J Cell Sci 2021; 134:272512. [PMID: 34657963 PMCID: PMC8627557 DOI: 10.1242/jcs.259192] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/13/2021] [Indexed: 01/20/2023] Open
Abstract
His domain protein tyrosine phosphatase (HD-PTP; also known as PTPN23) collaborates with endosomal sorting complexes required for transport (ESCRTs) to sort endosomal cargo into intralumenal vesicles, forming the multivesicular body (MVB). Completion of MVB sorting is accompanied by maturation of the endosome into a late endosome, an event that requires inactivation of the early endosomal GTPase Rab5 (herein referring to generically to all isoforms). Here, we show that HD-PTP links ESCRT function with endosomal maturation. HD-PTP depletion prevents MVB sorting, while also blocking cargo from exiting Rab5-rich endosomes. HD-PTP-depleted cells contain hyperphosphorylated Rabaptin-5 (also known as RABEP1), a cofactor for the Rab5 guanine nucleotide exchange factor Rabex-5 (also known as RABGEF1), although HD-PTP is unlikely to directly dephosphorylate Rabaptin-5. In addition, HD-PTP-depleted cells exhibit Rabaptin-5-dependent hyperactivation of Rab5. HD-PTP binds directly to Rabaptin-5, between its Rabex-5- and Rab5-binding domains. This binding reaction involves the ESCRT-0/ESCRT-III binding site in HD-PTP, which is competed for by an ESCRT-III peptide. Jointly, these findings indicate that HD-PTP may alternatively scaffold ESCRTs and modulate Rabex-5–Rabaptin-5 activity, thereby helping to coordinate the completion of MVB sorting with endosomal maturation. Summary: Sorting of endocytic cargo to the multivesicular body is accompanied by endosomal maturation. Here, we provide a potential mechanism by which these two processes are linked.
Collapse
Affiliation(s)
- Gabrielle Parkinson
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Peristera Roboti
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Ling Zhang
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Sandra Taylor
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| | - Philip Woodman
- Faculty of Biology, Medicine and Health, Manchester Academic and Health Science Centre, The University of Manchester, Manchester M13 9PT, UK
| |
Collapse
|
3
|
Qiao Y, Wang Z, Bunikyte R, Chen X, Jin S, Qi X, Cai D, Feng S. Cobalt chloride-simulated hypoxia elongates primary cilia in immortalized human retina pigment epithelial-1 cells. Biochem Biophys Res Commun 2021; 555:190-195. [PMID: 33823365 DOI: 10.1016/j.bbrc.2021.03.097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 11/20/2022]
Abstract
Primary cilia are microtubule-based organelles that are involved in sensing micro-environmental cues and regulating cellular homeostasis via triggering signaling cascades. Hypoxia is one of the most common environmental stresses that organ and tissue cells may often encounter during embryogenesis, cell differentiation, infection, inflammation, injury, cerebral and cardiac ischemia, or tumorigenesis. Although hypoxia has been reported to promote or inhibit primary ciliogenesis in different tissues or cultured cell lines, the role of hypoxia in ciliogenesis is controversial and still unclear. Here we investigated the primary cilia change under cobalt chloride (CoCl2)-simulated hypoxia in immortalized human retina pigment epithelial-1 (hTERT RPE-1) cells. We found CoCl2 treatment elongated primary cilia in a time- and dose-dependent manner. The prolonged cilia recovered back to near normal length when CoCl2 was washed out from the cell culture medium. Under CoCl2-simulated hypoxia, the protein expression levels of HIF-1/2α and acetylated-α-tubulin (cilia marker) were increased, while the protein expression level of Rabaptin-5 is decreased during hypoxia. Taken together, our results suggest that hypoxia may elongate primary cilia by downregulating Rabaptin-5 involved endocytosis. The coordination between endocytosis and ciliogenesis may be utilized by cells to adapt to hypoxia.
Collapse
Affiliation(s)
- Ying Qiao
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Zhengduo Wang
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Raimonda Bunikyte
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Xi Chen
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Shuang Jin
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Xufeng Qi
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China
| | - Dongqing Cai
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China.
| | - Shanshan Feng
- Key Laboratory of Regenerative Medicine, Ministry of Education, International Base of Collaboration for Science and Technology (JNU), The Ministry of Science and Technology & Guangdong Province, Department of Developmental and Regenerative Biology, Jinan University, Guangzhou, 510632, China.
| |
Collapse
|
4
|
Nag S, Rani S, Mahanty S, Bissig C, Arora P, Azevedo C, Saiardi A, van der Sluijs P, Delevoye C, van Niel G, Raposo G, Setty SRG. Rab4A organizes endosomal domains for sorting cargo to lysosome-related organelles. J Cell Sci 2018; 131:jcs.216226. [PMID: 30154210 PMCID: PMC6151265 DOI: 10.1242/jcs.216226] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 08/08/2018] [Indexed: 12/13/2022] Open
Abstract
Sorting endosomes (SEs) are the regulatory hubs for sorting cargo to multiple organelles, including lysosome-related organelles, such as melanosomes in melanocytes. In parallel, melanosome biogenesis is initiated from SEs with the processing and sequential transport of melanocyte-specific proteins toward maturing melanosomes. However, the mechanism of cargo segregation on SEs is largely unknown. Here, RNAi screening in melanocytes revealed that knockdown of Rab4A results in defective melanosome maturation. Rab4A-depletion increases the number of vacuolar endosomes and disturbs the cargo sorting, which in turn lead to the mislocalization of melanosomal proteins to lysosomes, cell surface and exosomes. Rab4A localizes to the SEs and forms an endosomal complex with the adaptor AP-3, the effector rabenosyn-5 and the motor KIF3, which possibly coordinates cargo segregation on SEs. Consistent with this, inactivation of rabenosyn-5, KIF3A or KIF3B phenocopied the defects observed in Rab4A-knockdown melanocytes. Further, rabenosyn-5 was found to associate with rabaptin-5 or Rabip4/4' (isoforms encoded by Rufy1) and differentially regulate cargo sorting from SEs. Thus, Rab4A acts a key regulator of cargo segregation on SEs.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Sudeshna Nag
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
| | - Shikha Rani
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
| | - Sarmistha Mahanty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
| | - Christin Bissig
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, F-75005, Paris, France
| | - Pooja Arora
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
| | - Cristina Azevedo
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Peter van der Sluijs
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Cedric Delevoye
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, F-75005, Paris, France.,Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), F-75005, Paris, France
| | - Guillaume van Niel
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, F-75005, Paris, France.,Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), F-75005, Paris, France
| | - Graca Raposo
- Institut Curie, PSL Research University, CNRS, UMR 144, Structure and Membrane Compartments, F-75005, Paris, France.,Institut Curie, PSL Research University, CNRS, UMR144, Cell and Tissue Imaging Facility (PICT-IBiSA), F-75005, Paris, France
| | - Subba Rao Gangi Setty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India 560 012
| |
Collapse
|
5
|
Zhang Z, Zhang T, Wang S, Gong Z, Tang C, Chen J, Ding J. Molecular mechanism for Rabex-5 GEF activation by Rabaptin-5. eLife 2014; 3. [PMID: 24957337 PMCID: PMC4102244 DOI: 10.7554/elife.02687] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 06/20/2014] [Indexed: 01/30/2023] Open
Abstract
Rabex-5 and Rabaptin-5 function together to activate Rab5 and further promote early endosomal fusion in endocytosis. The Rabex-5 GEF activity is autoinhibited by the Rabex-5 CC domain (Rabex-5CC) and activated by the Rabaptin-5 C2-1 domain (Rabaptin-5C21) with yet unknown mechanism. We report here the crystal structures of Rabex-5 in complex with the dimeric Rabaptin-5C21 (Rabaptin-5C212) and in complex with Rabaptin-5C212 and Rab5, along with biophysical and biochemical analyses. We show that Rabex-5CC assumes an amphipathic α-helix which binds weakly to the substrate-binding site of the GEF domain, leading to weak autoinhibition of the GEF activity. Binding of Rabaptin-5C21 to Rabex-5 displaces Rabex-5CC to yield a largely exposed substrate-binding site, leading to release of the GEF activity. In the ternary complex the substrate-binding site of Rabex-5 is completely exposed to bind and activate Rab5. Our results reveal the molecular mechanism for the regulation of the Rabex-5 GEF activity. DOI:http://dx.doi.org/10.7554/eLife.02687.001 Cells need to allow various molecules to pass through the plasma membrane on their surface. Some molecules have to enter the cell, whereas others have to leave. Cells rely on a process called endocytosis to move large molecules into the cell. This involves part of the membrane engulfing the molecule to form a ‘bubble’ around it. This bubble, which is called an endosome, then moves the molecule to final destination inside the cell. A protein called Rab5 controls how a new endosome is produced. However, before this can happen, various other molecules—including two proteins called Rabex-5 and Rabaptin-5—must activate the Rab5 protein. Exactly how these three proteins interact with each other was unknown. Zhang et al. used X-ray crystallography to examine the structures of the complexes formed when Rabex-5 and Rabaptin-5 bind to each other, both when Rab5 is present, and also when it is absent. Biochemical and biophysical experiments confirmed that the Rabex-5/Rabaptin-5 complex is able to activate Rab5. Zhang et al. also found that Rabex-5, on its own, folds so that the site that normally binds to Rab5 instead binds to a different part of Rabex-5, thus preventing endocytosis. However, when Rabaptin-5 forms a complex with Rabex-5, the Rab5 binding site is freed up. The Rabex-5/Rabaptin-5 complex can switch between a V shape and a linear structure. Binding to Rab5 stabilizes the linear form of the complex, which then helps activate Rab5, and subsequently the activated Rab5 can interact with other downstream molecules, triggering endocytosis. DOI:http://dx.doi.org/10.7554/eLife.02687.002
Collapse
Affiliation(s)
- Zhe Zhang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Tianlong Zhang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Shanshan Wang
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zhou Gong
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Chun Tang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China
| | - Jiangye Chen
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jianping Ding
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| |
Collapse
|