1
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Ko W, Lee E, Kim JE, Lim HH, Suh BC. The plasma membrane inner leaflet PI(4,5)P 2 is essential for the activation of proton-activated chloride channels. Nat Commun 2024; 15:7008. [PMID: 39143141 PMCID: PMC11324729 DOI: 10.1038/s41467-024-51400-y] [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: 10/07/2023] [Accepted: 08/07/2024] [Indexed: 08/16/2024] Open
Abstract
Proton-activated chloride (PAC) channels, ubiquitously expressed in tissues, regulate intracellular Cl- levels and cell death following acidosis. However, molecular mechanisms and signaling pathways involved in PAC channel modulation are largely unknown. Herein, we determine that phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] of the plasma membrane inner leaflet is essential for the proton activation of PAC channels. PI(4,5)P2 depletion by activating phosphatidylinositol 5-phosphatases or Gq protein-coupled muscarinic receptors substantially inhibits human PAC currents. In excised inside-out patches, PI(4,5)P2 application to the cytoplasmic side increases the currents. Structural simulation reveals that the putative PI(4,5)P2-binding site is localized within the cytosol in resting state but shifts to the cell membrane's inner surface in an activated state and interacts with inner leaflet PI(4,5)P2. Alanine neutralization of basic residues near the membrane-cytosol interface of the transmembrane helice 2 significantly attenuates PAC currents. Overall, our study uncovers a modulatory mechanism of PAC channel through inner membrane PI(4,5)P2.
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Affiliation(s)
- Woori Ko
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - Euna Lee
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
- Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), Daegu, 41068, Republic of Korea
| | - Jung-Eun Kim
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - Hyun-Ho Lim
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
- Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), Daegu, 41068, Republic of Korea
| | - Byung-Chang Suh
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea.
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2
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Stocks CJ, Li X, Stow JL. New advances in innate immune endosomal trafficking. Curr Opin Cell Biol 2024; 89:102395. [PMID: 38970837 DOI: 10.1016/j.ceb.2024.102395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/28/2024] [Accepted: 06/11/2024] [Indexed: 07/08/2024]
Abstract
The exocytic and endocytic intracellular trafficking pathways in innate immune cells are known for mediating the secretion of key inflammatory mediators or the internalization of growth factors, nutrients, antigens, cell debris, pathogens and even therapeutics, respectively. Inside cells, these pathways are intertwined as an elaborate network that supports the regulation of immune functions. Endosomal membranes host dynamic platforms for molecular complexes that control signaling and inflammatory responses. High content screens, coupled with elegant microscopy across the scale of resolving molecular complexes to tracking live cellular organelles, have been employed to generate the studies highlighted here. With a focus on deactivation of STING, scaffolding by SLC15A4/TASL complexes and macropinosome shrinkage via the chloride channel protein TMEM206, new studies are identifying molecules, molecular interactions and mechanisms for immune regulation throughout endosomal pathways.
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Affiliation(s)
- Claudia J Stocks
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Xichun Li
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Jennifer L Stow
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
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3
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Cai R, Scott O, Ye G, Le T, Saran E, Kwon W, Inpanathan S, Sayed BA, Botelho RJ, Saric A, Uderhardt S, Freeman SA. Pressure sensing of lysosomes enables control of TFEB responses in macrophages. Nat Cell Biol 2024; 26:1247-1260. [PMID: 38997458 DOI: 10.1038/s41556-024-01459-y] [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: 06/06/2023] [Accepted: 06/11/2024] [Indexed: 07/14/2024]
Abstract
Polymers are endocytosed and hydrolysed by lysosomal enzymes to generate transportable solutes. While the transport of diverse organic solutes across the plasma membrane is well studied, their necessary ongoing efflux from the endocytic fluid into the cytosol is poorly appreciated by comparison. Myeloid cells that employ specialized types of endocytosis, that is, phagocytosis and macropinocytosis, are highly dependent on such transport pathways to prevent the build-up of hydrostatic pressure that otherwise offsets lysosomal dynamics including vesiculation, tubulation and fission. Without undergoing rupture, we found that lysosomes incurring this pressure owing to defects in solute efflux, are unable to retain luminal Na+, which collapses its gradient with the cytosol. This cation 'leak' is mediated by pressure-sensitive channels resident to lysosomes and leads to the inhibition of mTORC1, which is normally activated by Na+-coupled amino acid transporters driven by the Na+ gradient. As a consequence, the transcription factors TFEB/TFE3 are made active in macrophages with distended lysosomes. In addition to their role in lysosomal biogenesis, TFEB/TFE3 activation causes the release of MCP-1/CCL2. In catabolically stressed tissues, defects in efflux of solutes from the endocytic pathway leads to increased monocyte recruitment. Here we propose that macrophages respond to a pressure-sensing pathway on lysosomes to orchestrate lysosomal biogenesis as well as myeloid cell recruitment.
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Affiliation(s)
- Ruiqi Cai
- Program in Cell Biology and Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ori Scott
- Program in Cell Biology and Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Gang Ye
- Program in Cell Biology and Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Trieu Le
- Program in Cell Biology and Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ekambir Saran
- Program in Cell Biology and Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Whijin Kwon
- Program in Cell Biology and Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Subothan Inpanathan
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Molecular Science Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Blayne A Sayed
- Program in Cell Biology and Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Roberto J Botelho
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Ontario, Canada
- Molecular Science Graduate Program, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Amra Saric
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- Program in Neurosciences and Mental Health, Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Stefan Uderhardt
- Department of Internal Medicine, Rheumatology and Immunology, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen, Erlangen, Germany
- Deutsches Zentrum für Immuntherapie, Universitätsklinikum Erlangen, Friedrich-Alexander University Erlangen, Erlangen, Germany
- Exploratory Research Unit, Optical Imaging Centre Erlangen, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Spencer A Freeman
- Program in Cell Biology and Peter Gilgan Centre for Research and Learning, Hospital for Sick Children, Toronto, Ontario, Canada.
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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4
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Hu M, Feng X, Liu Q, Liu S, Huang F, Xu H. The ion channels of endomembranes. Physiol Rev 2024; 104:1335-1385. [PMID: 38451235 DOI: 10.1152/physrev.00025.2023] [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: 06/30/2023] [Revised: 02/20/2024] [Accepted: 02/25/2024] [Indexed: 03/08/2024] Open
Abstract
The endomembrane system consists of organellar membranes in the biosynthetic pathway [endoplasmic reticulum (ER), Golgi apparatus, and secretory vesicles] as well as those in the degradative pathway (early endosomes, macropinosomes, phagosomes, autophagosomes, late endosomes, and lysosomes). These endomembrane organelles/vesicles work together to synthesize, modify, package, transport, and degrade proteins, carbohydrates, and lipids, regulating the balance between cellular anabolism and catabolism. Large ion concentration gradients exist across endomembranes: Ca2+ gradients for most endomembrane organelles and H+ gradients for the acidic compartments. Ion (Na+, K+, H+, Ca2+, and Cl-) channels on the organellar membranes control ion flux in response to cellular cues, allowing rapid informational exchange between the cytosol and organelle lumen. Recent advances in organelle proteomics, organellar electrophysiology, and luminal and juxtaorganellar ion imaging have led to molecular identification and functional characterization of about two dozen endomembrane ion channels. For example, whereas IP3R1-3 channels mediate Ca2+ release from the ER in response to neurotransmitter and hormone stimulation, TRPML1-3 and TMEM175 channels mediate lysosomal Ca2+ and H+ release, respectively, in response to nutritional and trafficking cues. This review aims to summarize the current understanding of these endomembrane channels, with a focus on their subcellular localizations, ion permeation properties, gating mechanisms, cell biological functions, and disease relevance.
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Affiliation(s)
- Meiqin Hu
- Department of Neurology and Department of Cardiology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, People's Republic of China
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Xinghua Feng
- Department of Neurology and Department of Cardiology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, People's Republic of China
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Qiang Liu
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Siyu Liu
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Fangqian Huang
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
| | - Haoxing Xu
- Department of Neurology and Department of Cardiology, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, People's Republic of China
- New Cornerstone Science Laboratory, Liangzhu Laboratory and School of Basic Medical Sciences, Zhejiang University, Hangzhou, People's Republic of China
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States
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5
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Polovitskaya MM, Rana T, Ullrich K, Murko S, Bierhals T, Vogt G, Stauber T, Kubisch C, Santer R, Jentsch TJ. Gain-of-function variants in CLCN7 cause hypopigmentation and lysosomal storage disease. J Biol Chem 2024; 300:107437. [PMID: 38838776 PMCID: PMC11261146 DOI: 10.1016/j.jbc.2024.107437] [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: 03/01/2024] [Revised: 05/08/2024] [Accepted: 05/23/2024] [Indexed: 06/07/2024] Open
Abstract
Together with its β-subunit OSTM1, ClC-7 performs 2Cl-/H+ exchange across lysosomal membranes. Pathogenic variants in either gene cause lysosome-related pathologies, including osteopetrosis and lysosomal storage. CLCN7 variants can cause recessive or dominant disease. Different variants entail different sets of symptoms. Loss of ClC-7 causes osteopetrosis and mostly neuronal lysosomal storage. A recently reported de novo CLCN7 mutation (p.Tyr715Cys) causes widespread severe lysosome pathology (hypopigmentation, organomegaly, and delayed myelination and development, "HOD syndrome"), but no osteopetrosis. We now describe two additional HOD individuals with the previously described p.Tyr715Cys and a novel p.Lys285Thr mutation, respectively. Both mutations decreased ClC-7 inhibition by PI(3,5)P2 and affected residues lining its binding pocket, and shifted voltage-dependent gating to less positive potentials, an effect partially conferred to WT subunits in WT/mutant heteromers. This shift predicts augmented pH gradient-driven Cl- uptake into vesicles. Overexpressing either mutant induced large lysosome-related vacuoles. This effect depended on Cl-/H+-exchange, as shown using mutants carrying uncoupling mutations. Fibroblasts from the p.Y715C patient also displayed giant vacuoles. This was not observed with p.K285T fibroblasts probably due to residual PI(3,5)P2 sensitivity. The gain of function caused by the shifted voltage-dependence of either mutant likely is the main pathogenic factor. Loss of PI(3,5)P2 inhibition will further increase current amplitudes, but may not be a general feature of HOD. Overactivity of ClC-7 induces pathologically enlarged vacuoles in many tissues, which is distinct from lysosomal storage observed with the loss of ClC-7 function. Osteopetrosis results from a loss of ClC-7, but osteoclasts remain resilient to increased ClC-7 activity.
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Affiliation(s)
- Maya M Polovitskaya
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Tanushka Rana
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Graduate program of Humboldt-Universität zu Berlin and Graduate School of the Max Delbrück Centre for Molecular Medicine (MDC), Berlin, Germany
| | - Kurt Ullrich
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Simona Murko
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Tatjana Bierhals
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Guido Vogt
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Tobias Stauber
- Institute for Molecular Medicine, Medical School Hamburg (MSH), Hamburg, Germany
| | - Christian Kubisch
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - René Santer
- Department of Pediatrics, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany.
| | - Thomas J Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany.
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6
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Chi P, Wang X, Li J, Yang H, Li K, Zhang Y, Lin S, Yu L, Liu S, Chen L, Ren R, Wu J, Huang Z, Geng J, Deng D. Molecular insights into the inhibition of proton-activated chloride channel by transfer RNA. Cell Res 2024:10.1038/s41422-024-00993-6. [PMID: 38942816 DOI: 10.1038/s41422-024-00993-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 06/16/2024] [Indexed: 06/30/2024] Open
Affiliation(s)
- Pengliang Chi
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Xiang Wang
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Jialu Li
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Hui Yang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Kaiju Li
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan, China
- Department of Laboratory Medicine, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China
| | - Yuqi Zhang
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Westlake Laboratory of Life Sciences and Biomedicine, Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Shiyi Lin
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Westlake Laboratory of Life Sciences and Biomedicine, Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Leiye Yu
- Kobilka Institute of Innovative Drug Discovery, School of Life and Health Sciences, the Chinese University of Hong Kong, Shenzhen, Guangdong, China
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Shiqi Liu
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Lu Chen
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Ruobing Ren
- Kobilka Institute of Innovative Drug Discovery, School of Life and Health Sciences, the Chinese University of Hong Kong, Shenzhen, Guangdong, China
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Jianping Wu
- Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Westlake Laboratory of Life Sciences and Biomedicine, Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing, China.
| | - Jia Geng
- Department of Laboratory Medicine, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, Sichuan, China.
| | - Dong Deng
- Department of Obstetrics, Key Laboratory of Birth Defects and Related Disease of Women and Children of MOE, State Key Laboratory of Biotherapy, West China Second Hospital, Sichuan University, Chengdu, Sichuan, China.
- Development and Related Diseases of Women and Children Key Laboratory of Sichuan Province, Sichuan University, Chengdu, Sichuan, China.
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7
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Wu Y, Hu X, Wei Z, Lin Q. Cellular Regulation of Macropinocytosis. Int J Mol Sci 2024; 25:6963. [PMID: 39000072 PMCID: PMC11241348 DOI: 10.3390/ijms25136963] [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: 05/16/2024] [Revised: 06/17/2024] [Accepted: 06/23/2024] [Indexed: 07/16/2024] Open
Abstract
Interest in macropinocytosis has risen in recent years owing to its function in tumorigenesis, immune reaction, and viral infection. Cancer cells utilize macropinocytosis to acquire nutrients to support their uncontrolled proliferation and energy consumption. Macropinocytosis, a highly dynamic endocytic and vesicular process, is regulated by a series of cellular signaling pathways. The activation of small GTPases in conjunction with phosphoinositide signaling pivotally regulates the process of macropinocytosis. In this review, we summarize important findings about the regulation of macropinocytosis and provide information to increase our understanding of the regulatory mechanism underlying it.
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Affiliation(s)
| | | | | | - Qiong Lin
- School of Medicine, Jiangsu University, Zhenjiang 212013, China; (Y.W.); (X.H.); (Z.W.)
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8
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Pissas KP, Gründer S, Tian Y. Functional expression of the proton sensors ASIC1a, TMEM206, and OGR1 together with BK Ca channels is associated with cell volume changes and cell death under strongly acidic conditions in DAOY medulloblastoma cells. Pflugers Arch 2024; 476:923-937. [PMID: 38627262 PMCID: PMC11139714 DOI: 10.1007/s00424-024-02964-7] [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: 02/05/2024] [Revised: 03/25/2024] [Accepted: 04/05/2024] [Indexed: 06/01/2024]
Abstract
Fast growing solid tumors are frequently surrounded by an acidic microenvironment. Tumor cells employ a variety of mechanisms to survive and proliferate under these harsh conditions. In that regard, acid-sensitive membrane receptors constitute a particularly interesting target, since they can affect cellular functions through ion flow and second messenger cascades. Our knowledge of these processes remains sparse, however, especially regarding medulloblastoma, the most common pediatric CNS malignancy. In this study, using RT-qPCR, whole-cell patch clamp, and Ca2+-imaging, we uncovered several ion channels and a G protein-coupled receptor, which were regulated directly or indirectly by low extracellular pH in DAOY and UW228 medulloblastoma cells. Acidification directly activated acid-sensing ion channel 1a (ASIC1a), the proton-activated Cl- channel (PAC, ASOR, or TMEM206), and the proton-activated G protein-coupled receptor OGR1. The resulting Ca2+ signal secondarily activated the large conductance calcium-activated potassium channel (BKCa). Our analyses uncover a complex relationship of these transmembrane proteins in DAOY cells that resulted in cell volume changes and induced cell death under strongly acidic conditions. Collectively, our results suggest that these ion channels in concert with OGR1 may shape the growth and evolution of medulloblastoma cells in their acidic microenvironment.
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Affiliation(s)
| | - Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Yuemin Tian
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, 52074, Aachen, Germany
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9
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Yoshie S, Kuriyama M, Maekawa M, Xu W, Niidome T, Futaki S, Hirose H. ATP2B4 is an essential gene for epidermal growth factor-induced macropinocytosis in A431 cells. Genes Cells 2024; 29:512-520. [PMID: 38597132 DOI: 10.1111/gtc.13118] [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: 02/14/2024] [Revised: 03/27/2024] [Accepted: 03/29/2024] [Indexed: 04/11/2024]
Abstract
Macropinocytosis (MPC) is a large-scale endocytosis pathway that involves actin-dependent membrane ruffle formation and subsequent ruffle closure to generate macropinosomes for the uptake of fluid-phase cargos. MPC is categorized into two types: constitutive and stimuli-induced. Constitutive MPC in macrophages relies on extracellular Ca2+ sensing by a calcium-sensing receptor. However, the link between stimuli-induced MPC and Ca2+ remains unclear. Here, we find that both intracellular and extracellular Ca2+ are required for epidermal growth factor (EGF)-induced MPC in A431 human epidermoid carcinoma cells. Through investigation of mammalian homologs of coelomocyte uptake defective (CUP) genes, we identify ATP2B4, encoding for a Ca2+ pump called the plasma membrane calcium ATPase 4 (PMCA4), as a Ca2+-related regulator of EGF-induced MPC. Knockout (KO) of ATP2B4, as well as depletion of extracellular/intracellular Ca2+, inhibited ruffle closure and macropinosome formation, without affecting ruffle formation. We demonstrate the importance of PMCA4 activity itself, independent of interactions with other proteins via its C-terminus known as a PDZ domain-binding motif. Additionally, we show that ATP2B4-KO reduces EGF-stimulated Ca2+ oscillation during MPC. Our findings suggest that EGF-induced MPC requires ATP2B4-dependent Ca2+ dynamics.
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Affiliation(s)
- Shunsuke Yoshie
- Institute for Chemical Research, Kyoto University, Uji, Japan
| | | | - Masashi Maekawa
- Division of Physiological Chemistry and Metabolism, Graduate School of Pharmaceutical Sciences, Keio University, Tokyo, Japan
| | - Wei Xu
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, Japan
| | - Takuro Niidome
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto, Japan
| | - Shiroh Futaki
- Institute for Chemical Research, Kyoto University, Uji, Japan
| | - Hisaaki Hirose
- Institute for Chemical Research, Kyoto University, Uji, Japan
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10
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Accogli A, Park YN, Lenk GM, Severino M, Scala M, Denecke J, Hempel M, Lessel D, Kortüm F, Salpietro V, de Marco P, Guerrisi S, Torella A, Nigro V, Srour M, Turro E, Labarque V, Freson K, Piatelli G, Capra V, Kitzman JO, Meisler MH. Biallelic loss-of-function variants of SLC12A9 cause lysosome dysfunction and a syndromic neurodevelopmental disorder. Genet Med 2024; 26:101097. [PMID: 38334070 DOI: 10.1016/j.gim.2024.101097] [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: 08/02/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/10/2024] Open
Abstract
PURPOSE Pathogenic variants of FIG4 generate enlarged lysosomes and neurological and developmental disorders. To identify additional genes regulating lysosomal volume, we carried out a genome-wide activation screen to detect suppression of enlarged lysosomes in FIG4-/- cells. METHODS The CRISPR-a gene activation screen utilized sgRNAs from the promoters of protein-coding genes. Fluorescence-activated cell sorting separated cells with correction of the enlarged lysosomes from uncorrected cells. Patient variants of SLC12A9 were identified by exome or genome sequencing and studied by segregation analysis and clinical characterization. RESULTS Overexpression of SLC12A9, a solute co-transporter, corrected lysosomal swelling in FIG4-/- cells. SLC12A9 (NP_064631.2) colocalized with LAMP2 at the lysosome membrane. Biallelic variants of SLC12A9 were identified in 3 unrelated probands with neurodevelopmental disorders. Common features included intellectual disability, skeletal and brain structural abnormalities, congenital heart defects, and hypopigmented hair. Patient 1 was homozygous for nonsense variant p.(Arg615∗), patient 2 was compound heterozygous for p.(Ser109Lysfs∗20) and a large deletion, and proband 3 was compound heterozygous for p.(Glu290Glyfs∗36) and p.(Asn552Lys). Fibroblasts from proband 1 contained enlarged lysosomes that were corrected by wild-type SLC12A9 cDNA. Patient variant p.(Asn552Lys) failed to correct the lysosomal defect. CONCLUSION Impaired function of SLC12A9 results in enlarged lysosomes and a recessive disorder with a recognizable neurodevelopmental phenotype.
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Affiliation(s)
- Andrea Accogli
- Division of Medical Genetics, Department of Specialized Medicine, McGill University Health Centre (MUHC), Montreal, QC, Canada; Department of Human Genetics, McGill University, Montreal, QC, Canada
| | - Young N Park
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Guy M Lenk
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | | | - Marcello Scala
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, Università Degli Studi di Genova, Genoa, Italy; Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Jonas Denecke
- University Children's Hospital, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Maja Hempel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Davor Lessel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Fanny Kortüm
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Vincenzo Salpietro
- Department of Neuromuscular Disorders, Queen Square Institute of Neurology, University College London, London, United Kingdom; Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, 67100, L'Aquila, Italy
| | | | | | - Annalaura Torella
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy; Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Vincenzo Nigro
- Telethon Institute of Genetics and Medicine (TIGEM), Naples, Italy; Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Myriam Srour
- Department of Human Genetics, McGill University, Montreal, QC, Canada; Department of Pediatrics, Division of Pediatric Neurology, McGill University, Montreal, QC, Canada; McGill University Health Center (MUHC) Research Institute, Montreal, QC, Canada; Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Ernest Turro
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY; Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Veerle Labarque
- Center for Molecular and Vascular Biology, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium; Paediatric Hemato-Oncology, University Hospitals Leuven, Leuven, Belgium
| | - Kathleen Freson
- Center for Molecular and Vascular Biology, Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Gianluca Piatelli
- Department of Neurosurgery, Gaslini Children's Hospital, Genoa, Italy
| | - Valeria Capra
- Genomics and Clinical Genetics, IRCCS Instituto G. Gaslini, Genoa, Italy
| | - Jacob O Kitzman
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
| | - Miriam H Meisler
- Department of Human Genetics, University of Michigan, Ann Arbor, MI.
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11
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Kappel S, Melek K, Ross-Kaschitza D, Hauert B, Gerber CE, Lochner M, Peinelt C. CBA (4-chloro-2-(2-chlorophenoxy)acetamido) benzoic acid) inhibits TMEM206 mediated currents and TMEM206 does not contribute to acid-induced cell death in colorectal cancer cells. Front Pharmacol 2024; 15:1369513. [PMID: 38515848 PMCID: PMC10955468 DOI: 10.3389/fphar.2024.1369513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 02/08/2024] [Indexed: 03/23/2024] Open
Abstract
Introduction: Upon activation at low pH, TMEM206 conducts Cl- ions across plasma and vesicular membranes. In a (patho)physiological context, TMEM206 was reported to contribute to acid-induced cell death in neurons, kidney and cervical epithelial cells. We investigated the role of TMEM206 in acid-induced cell death in colorectal cancer cells. In addition, we studied CBA as a new small molecule inhibitor for TMEM206. Methods: The role of TMEM206 in acid-induced cell death was studied with CRISPR/Cas9-mediated knockout and FACS analysis. The pharmacology of TMEM206 was determined with the patch clamp technique. Results: In colorectal cancer cells, TMEM206 is not a critical mediator of acid-induced cell death. CBA is a small molecule inhibitor of TMEM206 (IC50 = 9.55 µM) at low pH, at pH 6.0 inhibition is limited. Conclusion: CBA demonstrates effective and specific inhibition of TMEM206; however, its inhibitory efficacy is limited at pH 6.0. Despite this limitation, CBA is a potent inhibitor for functional studies at pH 4.5 and may be a promising scaffold for the development of future TMEM206 inhibitors.
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Affiliation(s)
| | | | | | | | | | | | - Christine Peinelt
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
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12
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Yau E, Yang L, Chen Y, Umstead TM, Stanley AE, Halstead ES, Gandhi CK, Yewdell JW, Chroneos ZC. SP-R210 isoforms of Myosin18A modulate endosomal sorting and recognition of influenza A virus infection in macrophages. Microbes Infect 2024; 26:105280. [PMID: 38135024 PMCID: PMC10948314 DOI: 10.1016/j.micinf.2023.105280] [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: 05/28/2023] [Revised: 12/12/2023] [Accepted: 12/17/2023] [Indexed: 12/24/2023]
Abstract
Influenza A virus (IAV) infection causes acute and often lethal inflammation in the lung. The role of macrophages in this adverse inflammation is partially understood. The surfactant protein A receptor 210 (SP-R210) consists of two isoforms, a long (L) SP-R210L and a short (S) SP-R210S isoform encoded by alternative splicing of the myosin 18A gene. We reported that disruption of SP-R210L enhances cytosolic and endosomal antiviral response pathways. Here, we report that SP-R210L antagonizes type I interferon β (IFNβ), as depletion of SP-R210L potentiates IFNβ secretion. SP-R210 antibodies enhance and attenuate IFNβ secretion in SP-R210L replete and deficient macrophages, respectively, indicating that SP-R210 isoform stoichiometry alters macrophage function intrinsically. This reciprocal response is coupled to unopposed and restricted expression of viral genes in control and SP-R210L-deficient macrophages, respectively. Human monocytic cells with sub-stoichiometric expression of SP-R210L resist IAV infection, whereas alveolar macrophages with increased abundance of SP-R210L permit viral gene expression similar to murine macrophages. Uptake and membrane binding studies show that lack of SP-R210 isoforms does not impair IAV binding and internalization. Lack of SP-R210L, however, results in macropinocytic retention of the virus that depends on both SP-R210S and interferon-inducible transmembrane protein-3 (IFITM3). Mass spectrometry and Western blot analyses indicate that SP-R210 isoforms modulate differential recruitment of the Rho-family GTPase RAC1 and guanine nucleotide exchange factors. Our study suggests that SP-R210 isoforms modulate RAC-dependent macropinosomal sorting of IAV to discrete endosomal and lysosomal compartments that either permit or prevent endolysosomal escape and inflammatory sensing of viral genomes in macrophages.
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Affiliation(s)
- Eric Yau
- Department of Pediatrics, Division of Perinatal-Neonatal Medicine, Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Linlin Yang
- Department of Pediatrics, Division of Perinatal-Neonatal Medicine, Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Yan Chen
- Department of Pediatrics, Division of Perinatal-Neonatal Medicine, Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Todd M Umstead
- Department of Pediatrics, Division of Perinatal-Neonatal Medicine, Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Anne E Stanley
- Mass Spectrometry Core, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - E Scott Halstead
- Department of Pediatrics, Division of Perinatal-Neonatal Medicine, Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Pediatrics, Division of Pediatric Critical Care Medicine, Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Chintan K Gandhi
- Department of Pediatrics, Division of Perinatal-Neonatal Medicine, Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - Jonathan W Yewdell
- Cellular Biology Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA
| | - Zissis C Chroneos
- Department of Pediatrics, Division of Perinatal-Neonatal Medicine, Pulmonary Immunology and Physiology Laboratory, Pennsylvania State University College of Medicine, Hershey, PA, USA; Department of Microbiology and Immunology, Pennsylvania State University College of Medicine, Hershey, PA, USA.
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13
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Kostritskaia Y, Klüssendorf M, Pan YE, Hassani Nia F, Kostova S, Stauber T. Physiological Functions of the Volume-Regulated Anion Channel VRAC/LRRC8 and the Proton-Activated Chloride Channel ASOR/TMEM206. Handb Exp Pharmacol 2024; 283:181-218. [PMID: 37468723 DOI: 10.1007/164_2023_673] [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] [Indexed: 07/21/2023]
Abstract
Volume-regulated anion channels (VRACs) and the acid-sensitive outwardly rectifying anion channel (ASOR) mediate flux of chloride and small organic anions. Although known for a long time, they were only recently identified at the molecular level. VRACs are heteromers consisting of LRRC8 proteins A to E. Combining the essential LRRC8A with different LRRC8 paralogues changes key properties of VRAC such as conductance or substrate selectivity, which is how VRACs are involved in multiple physiological functions including regulatory volume decrease, cell proliferation and migration, cell death, purinergic signalling, fat and glucose metabolism, insulin signalling, and spermiogenesis. VRACs are also involved in pathological conditions, such as the neurotoxic release of glutamate and aspartate. Certain VRACs are also permeable to larger, organic anions, including antibiotics and anti-cancer drugs, making them an interesting therapeutic target. ASOR, also named proton-activated chloride channel (PAC), is formed by TMEM206 homotrimers on the plasma membrane and on endosomal compartments where it mediates chloride flux in response to extracytosolic acidification and plays a role in the shrinking and maturation of macropinosomes. ASOR has been shown to underlie neuronal swelling which causes cell death after stroke as well as promoting the metastasis of certain cancers, making them intriguing therapeutic targets as well.
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Affiliation(s)
- Yulia Kostritskaia
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Malte Klüssendorf
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Yingzhou Edward Pan
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Fatemeh Hassani Nia
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Simona Kostova
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Tobias Stauber
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany.
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14
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Hu S, Zhang Q, Ou Z, Dang Y. Particle sorting method based on swirl induction. J Chem Phys 2023; 159:174901. [PMID: 37909455 DOI: 10.1063/5.0170783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 10/11/2023] [Indexed: 11/03/2023] Open
Abstract
Fluid-based methods for particle sorting demonstrate increasing appeal in many areas of biosciences due to their biocompatibility and cost-effectiveness. Herein, we construct a microfluidic sorting system based on a swirl microchip. The impact of microchannel velocity on the swirl stagnation point as well as particle movement is analyzed through simulation and experiment. Moreover, the quantitative mapping relationship between flow velocity and particle position distribution is established. With this foundation established, a particle sorting method based on swirl induction is proposed. Initially, the particle is captured by a swirl. Then, the Sorting Region into which the particle aims to enter is determined according to the sorting condition and particle characteristic. Subsequently, the velocities of the microchannels are adjusted to control the swirl, which will induce the particle to enter its corresponding Induction Region. Thereafter, the velocities are adjusted again to change the fluid field and drive the particle into a predetermined Sorting Region, hence the sorting is accomplished. We have extensively conducted experiments taking particle size or color as a sorting condition. An outstanding sorting success rate of 98.75% is achieved when dealing with particles within the size range of tens to hundreds of micrometers in radius, which certifies the effectiveness of the proposed sorting method. Compared to the existing sorting techniques, the proposed method offers greater flexibility. The adjustment of sorting conditions or particle parameters no longer requires complex chip redesign, because such sorting tasks can be successfully realized through simple microchannel velocities control.
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Affiliation(s)
- Shuai Hu
- School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510641, China
| | - Qin Zhang
- School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510641, China
| | - Zhiming Ou
- School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510641, China
| | - Yanping Dang
- School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510641, China
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15
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Zhang B, Zhang S, Polovitskaya MM, Yi J, Ye B, Li R, Huang X, Yin J, Neuens S, Balfroid T, Soblet J, Vens D, Aeby A, Li X, Cai J, Song Y, Li Y, Tartaglia M, Li Y, Jentsch TJ, Yang M, Liu Z. Molecular basis of ClC-6 function and its impairment in human disease. SCIENCE ADVANCES 2023; 9:eadg4479. [PMID: 37831762 PMCID: PMC10575590 DOI: 10.1126/sciadv.adg4479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Accepted: 09/08/2023] [Indexed: 10/15/2023]
Abstract
ClC-6 is a late endosomal voltage-gated chloride-proton exchanger that is predominantly expressed in the nervous system. Mutated forms of ClC-6 are associated with severe neurological disease. However, the mechanistic role of ClC-6 in normal and pathological states remains largely unknown. Here, we present cryo-EM structures of ClC-6 that guided subsequent functional studies. Previously unrecognized ATP binding to cytosolic ClC-6 domains enhanced ion transport activity. Guided by a disease-causing mutation (p.Y553C), we identified an interaction network formed by Y553/F317/T520 as potential hotspot for disease-causing mutations. This was validated by the identification of a patient with a de novo pathogenic variant p.T520A. Extending these findings, we found contacts between intramembrane helices and connecting loops that modulate the voltage dependence of ClC-6 gating and constitute additional candidate regions for disease-associated gain-of-function mutations. Besides providing insights into the structure, function, and regulation of ClC-6, our work correctly predicts hotspots for CLCN6 mutations in neurodegenerative disorders.
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Affiliation(s)
- Bing Zhang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Department of Anesthesiology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, 201204 Shanghai, China
| | - Sensen Zhang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Maya M. Polovitskaya
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
- Max-Delbrück-Centrum für Molekulare Medizin (MDC), 13125 Berlin, Germany
| | - Jingbo Yi
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Binglu Ye
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Department of Anesthesiology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, 201204 Shanghai, China
| | - Ruochong Li
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Xueying Huang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Department of Anesthesiology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, 201204 Shanghai, China
| | - Jian Yin
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Sebastian Neuens
- Department of Genetics, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Tom Balfroid
- Department of Pediatric Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Julie Soblet
- Department of Genetics, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
- Department of Genetics, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
- Interuniversity Institute of Bioinformatics in Brussels, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Daphné Vens
- Pediatric Intensive Care Unit, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Alec Aeby
- Department of Pediatric Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Xiaoling Li
- Wuya College of Innovation, Shenyang Pharmaceutical University, 110016 Shenyang, China
| | - Jinjin Cai
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203 Shanghai, China
| | - Yingcai Song
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Department of Anesthesiology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, 201204 Shanghai, China
| | - Yuanxi Li
- Institute for Cognitive Neurodynamics, School of Mathematics, East China University of Science and Technology, 200237 Shanghai, China
| | - Marco Tartaglia
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Yang Li
- Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203 Shanghai, China
- National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
- Max-Delbrück-Centrum für Molekulare Medizin (MDC), 13125 Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, 10117 Berlin, Germany
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
- Cryo-EM Facility Center, Southern University of Science & Technology, 518055 Shenzhen, Guangdong, China
| | - Zhiqiang Liu
- Shanghai Key Laboratory of Maternal Fetal Medicine, Shanghai Institute of Maternal-Fetal Medicine and Gynecologic Oncology, Department of Anesthesiology, Clinical and Translational Research Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, 201204 Shanghai, China
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16
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Yang C, Tian F, Hu M, Kang C, Ping M, Liu Y, Hu M, Xu H, Yu Y, Gao Z, Li P. Characterization of the role of TMEM175 in an in vitro lysosomal H + fluxes model. FEBS J 2023; 290:4641-4659. [PMID: 37165739 DOI: 10.1111/febs.16814] [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: 01/31/2023] [Revised: 04/06/2023] [Accepted: 05/09/2023] [Indexed: 05/12/2023]
Abstract
Lysosome acidification is a dynamic equilibrium of H+ influx and efflux across the membrane, which is crucial for cell physiology. The vacuolar H+ ATPase (V-ATPase) is responsible for the H+ influx or refilling of lysosomes. TMEM175 was identified as a novel H+ permeable channel on lysosomal membranes, and it plays a critical role in lysosome acidification. However, how TMEM175 participates in lysosomal acidification remains unknown. Here, we present evidence that TMEM175 regulates lysosomal H+ influx and efflux in enlarged lysosomes isolated from COS1 treated with vacuolin-1. By utilizing the whole-endolysosome patch-clamp recording technique, a series of integrated lysosomal H+ influx and efflux signals in a ten-of-second time scale under the physiological pH gradient (luminal pH 4.60, and cytosolic pH 7.20) was recorded from this in vitro system. Lysosomal H+ fluxes constitute both the lysosomal H+ refilling and releasing, and they are asymmetrical processes with distinct featured kinetics for each of the H+ fluxes. Lysosomal H+ fluxes are entirely abolished when TMEM175 losses of function in the F39V mutant and is blocked by the antagonist (2-GBI). Meanwhile, lysosomal H+ fluxes are modulated by the pH-buffering capacity of the lumen and the lysosomal glycosylated membrane proteins, lysosome-associated membrane protein 1 (LAMP1). We propose that the TMEM175-mediated lysosomal H+ fluxes model would provide novel thoughts for studying the pathology of Parkinson's disease and lysosome storage disorders.
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Affiliation(s)
- Chuanyan Yang
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
- Department of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Fuyun Tian
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
| | - Mei Hu
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
- Pharmacology Laboratory, Zhongshan Hospital, Guangzhou University of Chinese Medicine, China
| | - Chunlan Kang
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Meixuan Ping
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yiyao Liu
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
| | - Meiqin Hu
- Department of Molecular, Cellular, and Developmental Biology, The University of Michigan, Ann Arbor, Michigan, USA
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, The University of Michigan, Ann Arbor, Michigan, USA
| | - Ye Yu
- Department of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, China
| | - Zhaobing Gao
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ping Li
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
- University of Chinese Academy of Sciences, Beijing, China
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17
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Brodeur A, Migneault F, Lanoie M, Beillevaire D, Turgeon J, Karakeussian-Rimbaud A, Thibodeau N, Boilard É, Dieudé M, Hébert MJ. Apoptotic exosome-like vesicles transfer specific and functional mRNAs to endothelial cells by phosphatidylserine-dependent macropinocytosis. Cell Death Dis 2023; 14:449. [PMID: 37474514 PMCID: PMC10359336 DOI: 10.1038/s41419-023-05991-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 06/28/2023] [Accepted: 07/13/2023] [Indexed: 07/22/2023]
Abstract
Apoptosis of endothelial cells prompts the release of apoptotic exosome-like vesicles (ApoExos), subtype extracellular vesicles secreted by apoptotic cells after caspase-3 activation. ApoExos are different from both apoptotic bodies and classical exosomes in their protein and nucleic acid contents and functions. In contrast to classical apoptotic bodies, ApoExos induce immunogenic responses that can be maladaptive when not tightly regulated. In the present study, we elucidated the mechanisms by which ApoExos are internalized by endothelial cells, which leads to shared specific and functional mRNAs of importance to endothelial function. Using flow cytometry and confocal microscopy, we revealed that ApoExos were actively internalized by endothelial cells. SiRNA-induced inhibition of classical endocytosis pathways with pharmacological inhibitors showed that ApoExos were internalized via phosphatidylserine-dependent macropinocytosis independently of classical endocytosis pathways. An electron microscopy analysis revealed that ApoExos increased the macropinocytosis rate in endothelial cells, setting in motion a positive feedback loop that increased the amount of internalized ApoExos. Deep sequencing of total RNA revealed that ApoExos possessed a unique protein-coding RNA profile, with PCSK5 being the most abundant mRNA. Internalization of ApoExos by cells led to the transfer of this RNA content from the ApoExos to cells. Specifically, PCSK5 mRNA was transferred to cells that had taken up ApoExos, and these cells subsequently expressed PCSK5. Collectively, our findings suggest that macropinocytosis is an effective entry pathway for the delivery of RNAs carried by ApoExos and that these RNAs are functionally expressed by the endothelial cells that internalize them. As ApoExos express a specific mRNA signature, these results suggest new avenues to understand how ApoExos produced at sites of vascular injury impact vascular function.
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Affiliation(s)
- Alexandre Brodeur
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM) and Université de Montréal, Montréal, QC, Canada
- Canadian Donation and Transplantation Research Program (CDTRP), Edmonton, AL, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Francis Migneault
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM) and Université de Montréal, Montréal, QC, Canada
- Canadian Donation and Transplantation Research Program (CDTRP), Edmonton, AL, Canada
| | - Maude Lanoie
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM) and Université de Montréal, Montréal, QC, Canada
- Canadian Donation and Transplantation Research Program (CDTRP), Edmonton, AL, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Déborah Beillevaire
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM) and Université de Montréal, Montréal, QC, Canada
- Canadian Donation and Transplantation Research Program (CDTRP), Edmonton, AL, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Julie Turgeon
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM) and Université de Montréal, Montréal, QC, Canada
- Canadian Donation and Transplantation Research Program (CDTRP), Edmonton, AL, Canada
| | - Annie Karakeussian-Rimbaud
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM) and Université de Montréal, Montréal, QC, Canada
| | - Nicolas Thibodeau
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM) and Université de Montréal, Montréal, QC, Canada
| | - Éric Boilard
- Canadian Donation and Transplantation Research Program (CDTRP), Edmonton, AL, Canada
- Centre de Recherche, Centre Hospitalier Universitaire (CHU) de Québec-Université Laval, Département de Microbiologie et Immunologie, Québec, QC, Canada
| | - Mélanie Dieudé
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM) and Université de Montréal, Montréal, QC, Canada
- Canadian Donation and Transplantation Research Program (CDTRP), Edmonton, AL, Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
- Héma-Québec, Québec, QC, Canada
| | - Marie-Josée Hébert
- Centre de Recherche, Centre Hospitalier de l'Université de Montréal (CRCHUM) and Université de Montréal, Montréal, QC, Canada.
- Canadian Donation and Transplantation Research Program (CDTRP), Edmonton, AL, Canada.
- Département de Médecine, Université de Montréal, Montréal, QC, Canada.
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18
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Wu JZ, Zeziulia M, Kwon W, Jentsch TJ, Grinstein S, Freeman SA. ClC-7 drives intraphagosomal chloride accumulation to support hydrolase activity and phagosome resolution. J Cell Biol 2023; 222:e202208155. [PMID: 37010469 PMCID: PMC10072274 DOI: 10.1083/jcb.202208155] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 02/22/2023] [Accepted: 03/17/2023] [Indexed: 04/04/2023] Open
Abstract
Degradative organelles contain enzymes that function optimally at the acidic pH generated by the V-ATPase. The resulting transmembrane H+ gradient also energizes the secondary transport of several solutes, including Cl-. We report that Cl- influx, driven by the 2Cl-/H+ exchanger ClC-7, is necessary for the resolution of phagolysosomes formed by macrophages. Cl- transported via ClC-7 had been proposed to provide the counterions required for electrogenic H+ pumping. However, we found that deletion of ClC-7 had a negligible effect on phagosomal acidification. Instead, luminal Cl- was found to be required for activation of a wide range of phagosomal hydrolases including proteases, nucleases, and glycosidases. These findings argue that the primary role of ClC-7 is the accumulation of (phago)lysosomal Cl- and that the V-ATPases not only optimize the activity of degradative hydrolases by lowering the pH but, importantly, also play an indirect role in their activation by providing the driving force for accumulation of luminal Cl- that stimulates hydrolase activity allosterically.
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Affiliation(s)
- Jing Ze Wu
- Program in Cell Biology, Hospital for Sick Children, Toronto, Canada
- Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Mariia Zeziulia
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie and Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
- Graduate Program of the Freie Universität Berlin, Berlin, Germany
| | - Whijin Kwon
- Program in Cell Biology, Hospital for Sick Children, Toronto, Canada
| | - Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie and Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
- NeuroCure Cluster of Excellence, Charité University Medicine Berlin, Berlin, Germany
| | - Sergio Grinstein
- Program in Cell Biology, Hospital for Sick Children, Toronto, Canada
- Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Spencer A. Freeman
- Program in Cell Biology, Hospital for Sick Children, Toronto, Canada
- Department of Biochemistry, University of Toronto, Toronto, Canada
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19
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Liu LZ, Liu L, Shi ZH, Bian XL, Si ZR, Wang QQ, Xiang Y, Zhang Y. Amphibian pore-forming protein βγ-CAT drives extracellular nutrient scavenging under cell nutrient deficiency. iScience 2023; 26:106598. [PMID: 37128610 PMCID: PMC10148134 DOI: 10.1016/j.isci.2023.106598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 02/22/2023] [Accepted: 03/30/2023] [Indexed: 05/03/2023] Open
Abstract
Nutrient acquisition is essential for animal cells. βγ-CAT is a pore-forming protein (PFP) and trefoil factor complex assembled under tight regulation identified in toad Bombina maxima. Here, we reported that B. maxima cells secreted βγ-CAT under glucose, glutamine, and pyruvate deficiency to scavenge extracellular proteins for their nutrient supply and survival. AMPK signaling positively regulated the expression and secretion of βγ-CAT. The PFP complex selectively bound extracellular proteins and promoted proteins uptake through endolysosomal pathways. Elevated intracellular amino acids, enhanced ATP production, and eventually prolonged cell survival were observed in the presence of βγ-CAT and extracellular proteins. Liposome assays indicated that high concentration of ATP negatively regulated the opening of βγ-CAT channels. Collectively, these results uncovered that βγ-CAT is an essential element in cell nutrient scavenging under cell nutrient deficiency by driving vesicular uptake of extracellular proteins, providing a new paradigm for PFPs in cell nutrient acquisition and metabolic flexibility.
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Affiliation(s)
- Ling-Zhen Liu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Engineering Laboratory of Peptides of the Chinese Academy of Sciences, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan 650201, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Long Liu
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Engineering Laboratory of Peptides of the Chinese Academy of Sciences, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan 650201, China
- Human Aging Research Institute (HARI) and School of Life Sciences, Nanchang University, Nanchang, Jiangxi 330031, China
| | - Zhi-Hong Shi
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Engineering Laboratory of Peptides of the Chinese Academy of Sciences, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan 650201, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Xian-Ling Bian
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Engineering Laboratory of Peptides of the Chinese Academy of Sciences, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan 650201, China
- School of Life Science, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Zi-Ru Si
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Engineering Laboratory of Peptides of the Chinese Academy of Sciences, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan 650201, China
- School of Life Science, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Qi-Quan Wang
- Human Aging Research Institute (HARI) and School of Life Sciences, Nanchang University, Nanchang, Jiangxi 330031, China
| | - Yang Xiang
- Human Aging Research Institute (HARI) and School of Life Sciences, Nanchang University, Nanchang, Jiangxi 330031, China
- Corresponding author
| | - Yun Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Engineering Laboratory of Peptides of the Chinese Academy of Sciences, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan 650201, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
- Corresponding author
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20
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Salloum G, Bresnick AR, Backer JM. Macropinocytosis: mechanisms and regulation. Biochem J 2023; 480:335-362. [PMID: 36920093 DOI: 10.1042/bcj20210584] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/22/2023] [Accepted: 02/27/2023] [Indexed: 03/16/2023]
Abstract
Macropinocytosis is defined as an actin-dependent but coat- and dynamin-independent endocytic uptake process, which generates large intracellular vesicles (macropinosomes) containing a non-selective sampling of extracellular fluid. Macropinocytosis provides an important mechanism of immune surveillance by dendritic cells and macrophages, but also serves as an essential nutrient uptake pathway for unicellular organisms and tumor cells. This review examines the cell biological mechanisms that drive macropinocytosis, as well as the complex signaling pathways - GTPases, lipid and protein kinases and phosphatases, and actin regulatory proteins - that regulate macropinosome formation, internalization, and disposition.
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Affiliation(s)
- Gilbert Salloum
- Department of Molecular Pharamacology, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| | - Anne R Bresnick
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| | - Jonathan M Backer
- Department of Molecular Pharamacology, Albert Einstein College of Medicine, Bronx, NY, U.S.A
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, U.S.A
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21
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Mihaljević L, Ruan Z, Osei-Owusu J, Lü W, Qiu Z. Inhibition of the proton-activated chloride channel PAC by PIP 2. eLife 2023; 12:83935. [PMID: 36633397 PMCID: PMC9876566 DOI: 10.7554/elife.83935] [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: 10/04/2022] [Accepted: 12/18/2022] [Indexed: 01/13/2023] Open
Abstract
Proton-activated chloride (PAC) channel is a ubiquitously expressed pH-sensing ion channel, encoded by PACC1 (TMEM206). PAC regulates endosomal acidification and macropinosome shrinkage by releasing chloride from the organelle lumens. It is also found at the cell surface, where it is activated under pathological conditions related to acidosis and contributes to acid-induced cell death. However, the pharmacology of the PAC channel is poorly understood. Here, we report that phosphatidylinositol (4,5)-bisphosphate (PIP2) potently inhibits PAC channel activity. We solved the cryo-electron microscopy structure of PAC with PIP2 at pH 4.0 and identified its putative binding site, which, surprisingly, locates on the extracellular side of the transmembrane domain (TMD). While the overall conformation resembles the previously resolved PAC structure in the desensitized state, the TMD undergoes remodeling upon PIP2-binding. Structural and electrophysiological analyses suggest that PIP2 inhibits the PAC channel by stabilizing the channel in a desensitized-like conformation. Our findings identify PIP2 as a new pharmacological tool for the PAC channel and lay the foundation for future drug discovery targeting this channel.
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Affiliation(s)
- Ljubica Mihaljević
- Department of Physiology, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Zheng Ruan
- Department of Structural Biology, Van Andel InstituteGrand RapidsUnited States
| | - James Osei-Owusu
- Department of Physiology, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Wei Lü
- Department of Structural Biology, Van Andel InstituteGrand RapidsUnited States
| | - Zhaozhu Qiu
- Department of Physiology, Johns Hopkins University School of MedicineBaltimoreUnited States
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
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22
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Abstract
The discovery of NAADP-evoked Ca2+ release in sea urchin eggs and then as a ubiquitous Ca2+ mobilizing messenger has introduced several novel paradigms to our understanding of Ca2+ signalling, not least in providing a link between cell stimulation and Ca2+ release from lysosomes and other acidic Ca2+ storage organelles. In addition, the hallmark concentration-response relationship of NAADP-mediated Ca2+ release, shaped by striking activation/desensitization mechanisms, influences its actions as an intracellular messenger. There has been recent progress in our understanding of the molecular mechanisms underlying NAADP-evoked Ca2+ release, such as the identification of the endo-lysosomal two-pore channel family of cation channels (TPCs) as their principal target and the identity of NAADP-binding proteins that complex with them. The NAADP/TPC signalling axis has gained recent prominence in pathophysiology for their roles in such disease processes as neurodegeneration, tumorigenesis and cellular viral entry.
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Affiliation(s)
- Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, UK.
| | - Lianne C Davis
- Department of Pharmacology, University of Oxford, Oxford, UK
| | - Lora L Martucci
- Department of Pharmacology, University of Oxford, Oxford, UK
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23
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de Paz Linares GA, Freeman SA, Cai R. Using Ion Substitution and Fluid Indicators to Monitor Macropinosome Dynamics in Live Cells. Methods Mol Biol 2023; 2692:375-384. [PMID: 37365480 DOI: 10.1007/978-1-0716-3338-0_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
All forms of endocytosis involve the incidental uptake of fluid (pinocytosis). Macropinocytosis is a specialized type of endocytosis that results in the bulk ingestion of extracellular fluid via large (>0.2 μm) vacuoles called macropinosomes. The process is a means of immune surveillance, a point of entry for intracellular pathogens, and a source of nutrients for proliferating cancer cells. Macropinocytosis has also recently emerged as a tractable system that can be experimentally exploited to understand fluid handling in the endocytic pathway. In this chapter, we describe how stimulating macropinocytosis in the presence of extracellular fluids of a defined ionic composition can be combined with high-resolution microscopy to understand the role of ion transport in controlling membrane traffic.
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Affiliation(s)
| | - Spencer A Freeman
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada.
| | - Ruiqi Cai
- Program in Cell Biology, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, ON, Canada
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24
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Osei-Owusu J, Ruan Z, Mihaljević L, Matasic DS, Chen KH, Lü W, Qiu Z. Molecular mechanism underlying desensitization of the proton-activated chloride channel PAC. eLife 2022; 11:e82955. [PMID: 36547405 PMCID: PMC9779784 DOI: 10.7554/elife.82955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
Desensitization is a common property of membrane receptors, including ion channels. The newly identified proton-activated chloride (PAC) channel plays an important role in regulating the pH and size of organelles in the endocytic pathway, and is also involved in acid-induced cell death. However, how the PAC channel desensitizes is largely unknown. Here, we show by patch-clamp electrophysiological studies that PAC (also known as TMEM206/ASOR) undergoes pH-dependent desensitization upon prolonged acid exposure. Through structure-guided and comprehensive mutagenesis, we identified several residues critical for PAC desensitization, including histidine (H) 98, glutamic acid (E) 94, and aspartic acid (D) 91 at the extracellular extension of the transmembrane helix 1 (TM1), as well as E107, D109, and E250 at the extracellular domain (ECD)-transmembrane domain (TMD) interface. Structural analysis and molecular dynamic simulations revealed extensive interactions between residues at the TM1 extension and those at the ECD-TMD interface. These interactions likely facilitate PAC desensitization by stabilizing the desensitized conformation of TM1, which undergoes a characteristic rotational movement from the resting and activated states to the desensitized state. Our studies establish a new paradigm of channel desensitization in this ubiquitously expressed ion channel and pave the way for future investigation of its relevance in cellular physiology and disease.
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Affiliation(s)
- James Osei-Owusu
- Department of Physiology, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Zheng Ruan
- Department of Structural Biology, Van Andel InstituteGrand RapidsUnited States
| | - Ljubica Mihaljević
- Department of Physiology, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Daniel S Matasic
- Department of Medicine, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Kevin Hong Chen
- Department of Physiology, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Wei Lü
- Department of Structural Biology, Van Andel InstituteGrand RapidsUnited States
| | - Zhaozhu Qiu
- Department of Physiology, Johns Hopkins University School of MedicineBaltimoreUnited States
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
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25
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Hu M, Zhou N, Cai W, Xu H. Lysosomal solute and water transport. J Cell Biol 2022; 221:213536. [PMID: 36219209 PMCID: PMC9559593 DOI: 10.1083/jcb.202109133] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 09/05/2022] [Accepted: 09/22/2022] [Indexed: 11/22/2022] Open
Abstract
Lysosomes mediate hydrolase-catalyzed macromolecule degradation to produce building block catabolites for reuse. Lysosome function requires an osmo-sensing machinery that regulates osmolytes (ions and organic solutes) and water flux. During hypoosmotic stress or when undigested materials accumulate, lysosomes become swollen and hypo-functional. As a membranous organelle filled with cargo macromolecules, catabolites, ions, and hydrolases, the lysosome must have mechanisms that regulate its shape and size while coordinating content exchange. In this review, we discussed the mechanisms that regulate lysosomal fusion and fission as well as swelling and condensation, with a focus on solute and water transport mechanisms across lysosomal membranes. Lysosomal H+, Na+, K+, Ca2+, and Cl- channels and transporters sense trafficking and osmotic cues to regulate both solute flux and membrane trafficking. We also provide perspectives on how lysosomes may adjust the volume of themselves, the cytosol, and the cytoplasm through the control of lysosomal solute and water transport.
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Affiliation(s)
- Meiqin Hu
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China.,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI.,Liangzhu Laboratory & Zhejiang University Medical Center, Hangzhou, China
| | - Nan Zhou
- Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou, China.,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI.,Liangzhu Laboratory & Zhejiang University Medical Center, Hangzhou, China
| | - Weijie Cai
- Liangzhu Laboratory & Zhejiang University Medical Center, Hangzhou, China
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI.,Liangzhu Laboratory & Zhejiang University Medical Center, Hangzhou, China.,Department of Neurology, Second Affiliated Hospital of Zhejiang University Medical School, Hangzhou, China
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26
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Maekawa M, Natsume R, Arita M. Functional significance of ion channels during macropinosome resolution in immune cells. Front Physiol 2022; 13:1037758. [DOI: 10.3389/fphys.2022.1037758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/10/2022] [Indexed: 11/13/2022] Open
Abstract
Macropinocytosis is a unique type of endocytosis accompanied by membrane ruffle formation. Closure of membrane ruffles leads to the uptake of large volumes of fluid phase and, subsequently, the formation of large vacuoles termed macropinosomes. Immune cells, such as dendritic cells, T cells, and macrophages, endocytose the surrounding amino acids and pathogens via macropinocytosis either constitutively or in a stimulus-dependent fashion. This process is critical for cell migration, mammalian target of rapamycin complex 1 (mTORC1) activation, and antigen presentation. Large vacuoles are fragmented into tubules and smaller vesicles during the progression and maturation of macropinosomes in immune cells. This process is called “macropinosome resolution” and requires osmotically driven shrinkage of macropinosomes, which is controlled by ion channels present in them. The crenation of membranes on shrunken macropinosomes is recognized by curvature-sensing proteins and results in intracellular membrane trafficking. In this mini review, we highlight the recent progress in research on macropinosome resolution in macrophages, with a focus on ion channels (TPC1/2 for Na+ and TMEM206 for Cl−) that is required for macropinosome resolution. We also discuss the potential contribution of membrane lipids to this process.
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27
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Take a big sip and shrink it with ASOR. Pflugers Arch 2022; 474:1121-1122. [PMID: 36171315 DOI: 10.1007/s00424-022-02750-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 09/14/2022] [Accepted: 09/16/2022] [Indexed: 10/14/2022]
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28
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Two-pore channels: going with the flows. Biochem Soc Trans 2022; 50:1143-1155. [PMID: 35959977 PMCID: PMC9444070 DOI: 10.1042/bst20220229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/21/2022] [Accepted: 07/25/2022] [Indexed: 11/26/2022]
Abstract
In recent years, our understanding of the structure, mechanisms and functions of the endo-lysosomal TPC (two-pore channel) family have grown apace. Gated by the second messengers, NAADP and PI(3,5)P2, TPCs are an integral part of fundamental signal-transduction pathways, but their array and plasticity of cation conductances (Na+, Ca2+, H+) allow them to variously signal electrically, osmotically or chemically. Their relative tissue- and organelle-selective distribution, together with agonist-selective ion permeabilities provides a rich palette from which extracellular stimuli can choose. TPCs are emerging as mediators of immunity, cancer, metabolism, viral infectivity and neurodegeneration as this short review attests.
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