1
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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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2
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Yuan Y, Jaślan D, Rahman T, Bracher F, Grimm C, Patel S. Coordinating activation of endo-lysosomal two-pore channels and TRP mucolipins. J Physiol 2024; 602:1623-1636. [PMID: 38598430 DOI: 10.1113/jp283829] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 02/12/2024] [Indexed: 04/12/2024] Open
Abstract
Two-pore channels and TRP mucolipins are ubiquitous endo-lysosomal cation channels of pathophysiological relevance. Both are Ca2+-permeable and regulated by phosphoinositides, principally PI(3,5)P2. Accumulating evidence has uncovered synergistic channel activation by PI(3,5)P2 and endogenous metabolites such as the Ca2+ mobilizing messenger NAADP, synthetic agonists including approved drugs and physical cues such as voltage and osmotic pressure. Here, we provide an overview of this coordination.
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Affiliation(s)
- Yu Yuan
- Department of Cell and Developmental Biology, UCL, London, UK
| | - Dawid Jaślan
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilian University, Munich, Germany
| | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Franz Bracher
- Department of Pharmacy-Center for Drug Research, Ludwig-Maximilians University, Munich, Germany
| | - Christian Grimm
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, Ludwig-Maximilian University, Munich, Germany
- Immunology, Infection and Pandemic Research IIP, Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Frankfurt, Germany
| | - Sandip Patel
- Department of Cell and Developmental Biology, UCL, London, UK
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3
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Wang Z, Chen M, Su Q, Morais TDC, Wang Y, Nazginov E, Pillai AR, Qian F, Shi Y, Yu Y. Molecular and structural basis of the dual regulation of the polycystin-2 ion channel by small-molecule ligands. Proc Natl Acad Sci U S A 2024; 121:e2316230121. [PMID: 38483987 PMCID: PMC10962963 DOI: 10.1073/pnas.2316230121] [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: 09/21/2023] [Accepted: 02/12/2024] [Indexed: 03/19/2024] Open
Abstract
Mutations in the PKD2 gene, which encodes the polycystin-2 (PC2, also called TRPP2) protein, lead to autosomal dominant polycystic kidney disease (ADPKD). As a member of the transient receptor potential (TRP) channel superfamily, PC2 functions as a non-selective cation channel. The activation and regulation of the PC2 channel are largely unknown, and direct binding of small-molecule ligands to this channel has not been reported. In this work, we found that most known small-molecule agonists of the mucolipin TRP (TRPML) channels inhibit the activity of the PC2_F604P, a gain-of-function mutant of the PC2 channel. However, two of them, ML-SA1 and SF-51, have dual regulatory effects, with low concentration further activating PC2_F604P, and high concentration leading to inactivation of the channel. With two cryo-electron microscopy (cryo-EM) structures, a molecular docking model, and mutagenesis results, we identified two distinct binding sites of ML-SA1 in PC2_F604P that are responsible for activation and inactivation, respectively. These results provide structural and functional insights into how ligands regulate PC2 channel function through unusual mechanisms and may help design compounds that are more efficient and specific in regulating the PC2 channel and potentially also for ADPKD treatment.
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Affiliation(s)
- Zhifei Wang
- Department of Biological Sciences, St. John’s University, Queens, NY11375
| | - Mengying Chen
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang province310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang province310024, China
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Qiang Su
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang province310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang province310024, China
| | - Tiago D. C. Morais
- Department of Biological Sciences, St. John’s University, Queens, NY11375
| | - Yan Wang
- Department of Biological Sciences, St. John’s University, Queens, NY11375
| | - Elianna Nazginov
- Department of Biological Sciences, St. John’s University, Queens, NY11375
| | - Akhilraj R. Pillai
- Department of Biological Sciences, St. John’s University, Queens, NY11375
| | - Feng Qian
- Division of Nephrology, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD21201
| | - Yigong Shi
- Research Center for Industries of the Future, Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang province310024, China
- Westlake Laboratory of Life Sciences and Biomedicine, Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, Zhejiang province310024, China
- Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing100084, China
| | - Yong Yu
- Department of Biological Sciences, St. John’s University, Queens, NY11375
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4
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Huang J, Korsunsky A, Yazdani M, Chen J. Targeting TRP channels: recent advances in structure, ligand binding, and molecular mechanisms. Front Mol Neurosci 2024; 16:1334370. [PMID: 38273937 PMCID: PMC10808746 DOI: 10.3389/fnmol.2023.1334370] [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: 11/07/2023] [Accepted: 12/26/2023] [Indexed: 01/27/2024] Open
Abstract
Transient receptor potential (TRP) channels are a large and diverse family of transmembrane ion channels that are widely expressed, have important physiological roles, and are associated with many human diseases. These proteins are actively pursued as promising drug targets, benefitting greatly from advances in structural and mechanistic studies of TRP channels. At the same time, the complex, polymodal activation and regulation of TRP channels have presented formidable challenges. In this short review, we summarize recent progresses toward understanding the structural basis of TRP channel function, as well as potential ligand binding sites that could be targeted for therapeutics. A particular focus is on the current understanding of the molecular mechanisms of TRP channel activation and regulation, where many fundamental questions remain unanswered. We believe that a deeper understanding of the functional mechanisms of TRP channels will be critical and likely transformative toward developing successful therapeutic strategies targeting these exciting proteins. This endeavor will require concerted efforts from computation, structural biology, medicinal chemistry, electrophysiology, pharmacology, drug safety and clinical studies.
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Affiliation(s)
- Jian Huang
- Department of Chemistry, University of Massachusetts, Amherst, MA, United States
| | - Aron Korsunsky
- Department of Chemistry, University of Massachusetts, Amherst, MA, United States
| | - Mahdieh Yazdani
- Modeling and Informatics, Merck & Co., Inc., West Point, PA, United States
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA, United States
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5
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Anand S, Rajagopal S. A Comprehensive Review on the Regulatory Action of TRP Channels: A Potential Therapeutic Target for Nociceptive Pain. Neurosci Insights 2023; 18:26331055231220340. [PMID: 38146332 PMCID: PMC10749524 DOI: 10.1177/26331055231220340] [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: 08/04/2023] [Accepted: 11/28/2023] [Indexed: 12/27/2023] Open
Abstract
The transient receptor potential (TRP) superfamily of ion channels in humans comprises voltage-gated, non-selective cation channels expressed both in excitable as well as non-excitable cells. Four TRP channel subunits associate to create functional homo- or heterotetramers that allow the influx of calcium, sodium, and/or potassium. These channels are highly abundant in the brain and kidney and are important mediators of diverse biological functions including thermosensation, vascular tone, flow sensing in the kidney and irritant stimuli sensing. Inherited or acquired dysfunction of TRP channels influences cellular functions and signaling pathways resulting in multifaceted disorders affecting skeletal, renal, cardiovascular, and nervous systems. Studies have demonstrated the involvement of these channels in the generation and transduction of pain. Based on the multifaceted role orchestrated by these TRP channels, modulation of the activity of these channels presents an important strategy to influence cellular function by regulating intracellular calcium levels as well as membrane excitability. Therefore, there has been a remarkable pharmaceutical inclination toward TRP channels as therapeutic interventions. Several candidate drugs influencing the activity of these channels are already in the clinical trials pipeline. The present review encompasses the current understanding of TRP channels and TRP modulators in pain and pain management.
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Affiliation(s)
- Santosh Anand
- Department of Biotechnology, School of Applied Sciences, REVA University, Bengaluru, Karnataka, India
| | - Senthilkumar Rajagopal
- Department of Biotechnology, School of Applied Sciences, REVA University, Bengaluru, Karnataka, India
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6
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Zhu MY, Wang T, Wang HD, Wang HZ, Chen HY, Zhang S, Guo YJ, Li H, Hui H. LW-213 induces immunogenic tumor cell death via ER stress mediated by lysosomal TRPML1. Cancer Lett 2023; 577:216435. [PMID: 37806516 DOI: 10.1016/j.canlet.2023.216435] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/24/2023] [Accepted: 10/04/2023] [Indexed: 10/10/2023]
Abstract
Dying tumor cells release biological signals that exhibit antigenicity, activate cytotoxic T lymphocytes, and induce immunogenic cell death (ICD), playing a key role in immune surveillance. We demonstrate that the flavonoid LW-213 activates endoplasmic reticulum stress (ERS) in different tumor cells and that the lysosomal calcium channel TRPML1 mediates the ERS process in human cellular lymphoma Hut-102 cells. Apoptotic tumor cells induced by ERS often possess immunogenicity. Tumor cells treated with LW-213 exhibit damage-associated molecular patterns (DAMPs), including calreticulin translocation to the plasma membrane and extracellular release of ATP and HMGB1. When co-cultured with antigen-presenting cells (APCs), LW-213-treated tumor cells activated APCs. Two groups of C57BL/6J mice were inoculated with Lewis cells: a "vaccine group", which demonstrated that LW-213-treated tumor cells promote the maturation of dendritic cells and increase CD8+ T cells infiltration in the tumor microenvironment and a "pharmacodynamic group", treated with a combination of LW-213 and PD1/PD-L1 inhibitor (BMS-1), which reduced tumor growth and significantly prolonged the survival time of mice in the "pharmacodynamic group". Therefore, LW-213 can be developed as a novel ICD inducer, providing a new concept for antitumor immunotherapy.
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Affiliation(s)
- Meng-Yuan Zhu
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Ting Wang
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Hai-di Wang
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Hong-Zheng Wang
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Hong-Yu Chen
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Shuai Zhang
- The Affiliated Cancer Hospital of Nanjing Medical University, Nanjing, People's Republic of China
| | - Yong-Jian Guo
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, People's Republic of China
| | - Hui Li
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, People's Republic of China.
| | - Hui Hui
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Carcinogenesis and Intervention, Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education, Jiangsu Key Laboratory of Drug Design and Optimization, China Pharmaceutical University, Nanjing, People's Republic of China.
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7
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Cunha MR, Catta-Preta CMC, Takarada JE, Moreira GA, Massirer KB, Couñago RM. A novel BRET-based assay to investigate binding and residence times of unmodified ligands to the human lysosomal ion channel TRPML1 in intact cells. J Biol Chem 2023:104807. [PMID: 37172730 DOI: 10.1016/j.jbc.2023.104807] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/17/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Here we report a Bioluminescence Resonance Energy Transfer (BRET) assay as a novel way to investigate the binding of unlabeled ligands to the human Transient Receptor Potential Mucolipin 1 (hTRPML1), a lysosomal ion channel involved in several genetic diseases and cancer progression. This novel BRET assay can be used to determine equilibrium and kinetic binding parameters of unlabeled compounds to hTRPML1 using intact human-derived cells, thus complementing the information obtained using functional assays based on ion channel activation. We expect this new BRET assay to expedite the identification and optimization of cell-permeable ligands that interact with hTRPML1 within the physiologically-relevant environment of lysosomes.
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Affiliation(s)
- Micael R Cunha
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil.
| | - Carolina M C Catta-Preta
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil; Current address: Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Jéssica E Takarada
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil
| | - Gabriela A Moreira
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil
| | - Katlin B Massirer
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil.
| | - Rafael M Couñago
- Center of Medicinal Chemistry (CQMED), Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas, Av. Dr. André Tosello 550, 13083-886 Campinas, Brazil; Structural Genomics Consortium and Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States.
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8
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Wahl-Schott C, Freichel M, Hennis K, Philippaert K, Ottenheijm R, Tsvilovskyy V, Varbanov H. Characterization of Endo-Lysosomal Cation Channels Using Calcium Imaging. Handb Exp Pharmacol 2023; 278:277-304. [PMID: 36894791 DOI: 10.1007/164_2023_637] [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: 03/11/2023]
Abstract
Endo-lysosomes are membrane-bound acidic organelles that are involved in endocytosis, recycling, and degradation of extracellular and intracellular material. The membranes of endo-lysosomes express several Ca2+-permeable cation ion channels, including two-pore channels (TPC1-3) and transient receptor potential mucolipin channels (TRPML1-3). In this chapter, we will describe four different state-of-the-art Ca2+ imaging approaches, which are well-suited to investigate the function of endo-lysosomal cation channels. These techniques include (1) global cytosolic Ca2+ measurements, (2) peri-endo-lysosomal Ca2+ imaging using genetically encoded Ca2+ sensors that are directed to the cytosolic endo-lysosomal membrane surface, (3) Ca2+ imaging of endo-lysosomal cation channels, which are engineered in order to redirect them to the plasma membrane in combination with approaches 1 and 2, and (4) Ca2+ imaging by directing Ca2+ indicators to the endo-lysosomal lumen. Moreover, we will review useful small molecules, which can be used as valuable tools for endo-lysosomal Ca2+ imaging. Rather than providing complete protocols, we will discuss specific methodological issues related to endo-lysosomal Ca2+ imaging.
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Affiliation(s)
- Christian Wahl-Schott
- Institut für Kardiovaskuläre Physiologie und Pathophysiologie, Lehrstuhl für Vegetative Physiologie, Biomedizinisches Zentrum, Ludwig-Maximilians-Universität München, München, Germany.
| | - Marc Freichel
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany. .,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany.
| | - Konstantin Hennis
- Institut für Kardiovaskuläre Physiologie und Pathophysiologie, Lehrstuhl für Vegetative Physiologie, Biomedizinisches Zentrum, Ludwig-Maximilians-Universität München, München, Germany
| | - Koenraad Philippaert
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany
| | - Roger Ottenheijm
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany
| | - Volodymyr Tsvilovskyy
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany.,DZHK (German Centre for Cardiovascular Research), Heidelberg/Mannheim, Germany
| | - Hristo Varbanov
- Institut für Neurophysiologie, Medizinische Hochschule Hannover(MHH), Hannover, Germany
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9
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Yelshanskaya MV, Sobolevsky AI. Ligand-Binding Sites in Vanilloid-Subtype TRP Channels. Front Pharmacol 2022; 13:900623. [PMID: 35652046 PMCID: PMC9149226 DOI: 10.3389/fphar.2022.900623] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 04/06/2022] [Indexed: 02/02/2023] Open
Abstract
Vanilloid-subfamily TRP channels TRPV1-6 play important roles in various physiological processes and are implicated in numerous human diseases. Advances in structural biology, particularly the "resolution revolution" in cryo-EM, have led to breakthroughs in molecular characterization of TRPV channels. Structures with continuously improving resolution uncover atomic details of TRPV channel interactions with small molecules and protein-binding partners. Here, we provide a classification of structurally characterized binding sites in TRPV channels and discuss the progress that has been made by structural biology combined with mutagenesis, functional recordings, and molecular dynamics simulations toward understanding of the molecular mechanisms of ligand action. Given the similarity in structural architecture of TRP channels, 16 unique sites identified in TRPV channels may be shared between TRP channel subfamilies, although the chemical identity of a particular ligand will likely depend on the local amino-acid composition. The characterized binding sites and molecular mechanisms of ligand action create a diversity of druggable targets to aid in the design of new molecules for tuning TRP channel function in disease conditions.
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Affiliation(s)
| | - Alexander I. Sobolevsky
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, United States
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10
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Rendezvous with PI(3,5)P2 - a rapalog gets caught opening TRPML1. Cell Calcium 2022; 105:102597. [DOI: 10.1016/j.ceca.2022.102597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 05/12/2022] [Indexed: 11/17/2022]
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11
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TRPML1-induced autophagy inhibition triggers mitochondrial mediated apoptosis. Cancer Lett 2022; 541:215752. [DOI: 10.1016/j.canlet.2022.215752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 05/18/2022] [Accepted: 05/19/2022] [Indexed: 01/18/2023]
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12
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Chen CC, Krogsaeter E, Kuo CY, Huang MC, Chang SY, Biel M. Endolysosomal cation channels point the way towards precision medicine of cancer and infectious diseases. Biomed Pharmacother 2022; 148:112751. [PMID: 35240524 DOI: 10.1016/j.biopha.2022.112751] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 11/02/2022] Open
Abstract
Infectious diseases and cancer are among the key medical challenges that humankind is facing today. A growing amount of evidence suggests that ion channels in the endolysosomal system play a crucial role in the pathology of both groups of diseases. The development of advanced patch-clamp technologies has allowed us to directly characterize ion fluxes through endolysosomal ion channels in their native environments. Endolysosomes are essential organelles for intracellular transport, digestion and metabolism, and maintenance of homeostasis. The endolysosomal ion channels regulate the function of the endolysosomal system through four basic mechanisms: calcium release, control of membrane potential, pH change, and osmolarity regulation. In this review, we put particular emphasis on the endolysosomal cation channels, including TPC2 and TRPML2, which are particularly important in monocyte function. We discuss existing endogenous and synthetic ligands of these channels and summarize current knowledge of their impact on channel activity and function in different cell types. Moreover, we summarize recent findings on the importance of TPC2 and TRPML2 channels as potential drug targets for the prevention and treatment of the emerging infectious diseases and cancer.
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Affiliation(s)
- Cheng-Chang Chen
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan.
| | | | - Ching-Ying Kuo
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Min-Chuan Huang
- Graduate Institute of Anatomy and Cell Biology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Sui-Yuan Chang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Martin Biel
- Department of Pharmacy, Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
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13
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Structural mechanism of allosteric activation of TRPML1 by PI(3,5)P 2 and rapamycin. Proc Natl Acad Sci U S A 2022; 119:2120404119. [PMID: 35131932 PMCID: PMC8851561 DOI: 10.1073/pnas.2120404119] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2022] [Indexed: 12/22/2022] Open
Abstract
Rapamycin is a specific inhibitor of mammalian target of rapamycin (mTOR). Rapamycin can also activate transient receptor potential mucolipin 1 (TRPML1), a phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2]–gated lysosomal cation channel whose loss-of-function mutations directly cause mucolipidosis type IV disease. We determined the high-resolution cryoelectron microscopy structures of TRPML1 in various ligand-bound states, including the open TRPML1 in complex with PI(3,5)P2 and a rapamycin analog at 2.1 Å. These structures reveal how rapamycin and PI(3,5)P2 bind at two distinct sites and allosterically activate the channel. Considering the high potency of TRPML1 activation by rapamycin and PI(3,5)P2, it is conceivable that some pharmacological effects from the therapeutic use of rapamycin may come from the TRPML1-dependent mechanism rather than mTOR inhibition. Transient receptor potential mucolipin 1 (TRPML1) is a Ca2+-permeable, nonselective cation channel ubiquitously expressed in the endolysosomes of mammalian cells and its loss-of-function mutations are the direct cause of type IV mucolipidosis (MLIV), an autosomal recessive lysosomal storage disease. TRPML1 is a ligand-gated channel that can be activated by phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2] as well as some synthetic small-molecule agonists. Recently, rapamycin has also been shown to directly bind and activate TRPML1. Interestingly, both PI(3,5)P2 and rapamycin have low efficacy in channel activation individually but together they work cooperatively and activate the channel with high potency. To reveal the structural basis underlying the synergistic activation of TRPML1 by PI(3,5)P2 and rapamycin, we determined the high-resolution cryoelectron microscopy (cryo-EM) structures of the mouse TRPML1 channel in various states, including apo closed, PI(3,5)P2-bound closed, and PI(3,5)P2/temsirolimus (a rapamycin analog)-bound open states. These structures, combined with electrophysiology, elucidate the molecular details of ligand binding and provide structural insight into how the TRPML1 channel integrates two distantly bound ligand stimuli and facilitates channel opening.
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Gan N, Jiang Y. Structural biology of cation channels important for lysosomal calcium release. Cell Calcium 2022; 101:102519. [PMID: 34952412 PMCID: PMC8752501 DOI: 10.1016/j.ceca.2021.102519] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 01/03/2023]
Abstract
Calcium is one of the most important second messengers in cells. The uptake and release of calcium ions are conducted by channels and transporters. Inside a eukaryotic cell, calcium is stored in intracellular organelles including the endoplasmic reticulum (ER), mitochondrion, and lysosome. Lysosomes are acid membrane-bounded organelles serving as the crucial degradation and recycling center of the cell. Lysosomes involve in multiple important signaling events, including nutrient sensing, lipid metabolism, and trafficking. Hitherto, two lysosomal cation channel families have been suggested to function as calcium release channels, namely the Two-pore Channel (TPC) family, and the Transient Receptor Potential Channel Mucolipin (TRPML) family. Additionally, a few plasma membrane calcium channels have also been found in the lysosomal membrane under certain circumstances. In this review, we will discuss the structural mechanism of the cation channels that may be important for lysosomal calcium release, primarily focusing on the TPCs and TRPMLs.
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Affiliation(s)
- Ninghai Gan
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas 75390 USA,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390 USA
| | - Youxing Jiang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas 75390 USA,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390 USA
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15
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Du W, Gu M, Hu M, Pinchi P, Chen W, Ryan M, Nold T, Bannaga A, Xu H. Lysosomal Zn 2+ release triggers rapid, mitochondria-mediated, non-apoptotic cell death in metastatic melanoma. Cell Rep 2021; 37:109848. [PMID: 34686351 PMCID: PMC8559338 DOI: 10.1016/j.celrep.2021.109848] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 08/16/2021] [Accepted: 09/27/2021] [Indexed: 01/18/2023] Open
Abstract
During tumor progression, lysosome function is often maladaptively upregulated to match the high energy demand required for cancer cell hyper-proliferation and invasion. Here, we report that mucolipin TRP channel 1 (TRPML1), a lysosomal Ca2+ and Zn2+ release channel that regulates multiple aspects of lysosome function, is dramatically upregulated in metastatic melanoma cells compared with normal cells. TRPML-specific synthetic agonists (ML-SAs) are sufficient to induce rapid (within hours) lysosomal Zn2+-dependent necrotic cell death in metastatic melanoma cells while completely sparing normal cells. ML-SA-caused mitochondria swelling and dysfunction lead to cellular ATP depletion. While pharmacological inhibition or genetic silencing of TRPML1 in metastatic melanoma cells prevents such cell death, overexpression of TRPML1 in normal cells confers ML-SA vulnerability. In the melanoma mouse models, ML-SAs exhibit potent in vivo efficacy of suppressing tumor progression. Hence, targeting maladaptively upregulated lysosome machinery can selectively eradicate metastatic tumor cells in vitro and in vivo.
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Affiliation(s)
- Wanlu Du
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 4104 Biological Sciences Building, 1105 North University Ave., Ann Arbor, MI 48109, USA.
| | - Mingxue Gu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 4104 Biological Sciences Building, 1105 North University Ave., Ann Arbor, MI 48109, USA
| | - Meiqin Hu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 4104 Biological Sciences Building, 1105 North University Ave., Ann Arbor, MI 48109, USA
| | - Prateeksunder Pinchi
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 4104 Biological Sciences Building, 1105 North University Ave., Ann Arbor, MI 48109, USA
| | - Wei Chen
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 4104 Biological Sciences Building, 1105 North University Ave., Ann Arbor, MI 48109, USA
| | - Michael Ryan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 4104 Biological Sciences Building, 1105 North University Ave., Ann Arbor, MI 48109, USA
| | - Timothy Nold
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 4104 Biological Sciences Building, 1105 North University Ave., Ann Arbor, MI 48109, USA
| | - Ahmed Bannaga
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 4104 Biological Sciences Building, 1105 North University Ave., Ann Arbor, MI 48109, USA
| | - Haoxing Xu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 4104 Biological Sciences Building, 1105 North University Ave., Ann Arbor, MI 48109, USA
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