1
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Hu Y, Qin J, Ma Y, Yang R, Liu X, Shi C. Comprehensive review on the novel immunotherapy target: Leucine-rich repeat-containing 8A/volume-regulated anion channel. Int J Biol Sci 2024; 20:3881-3891. [PMID: 39113714 PMCID: PMC11302880 DOI: 10.7150/ijbs.95933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 06/28/2024] [Indexed: 08/10/2024] Open
Abstract
Leucine-rich repeat-containing 8A (LRRC8A) is a key component of the volume-regulated anion channel (VRAC) that influences essential homeostatic processes in various immune cells. These processes include the regulation of cell volume and membrane potential and the facilitation of the transport of organic agents used as anticancer drugs and immune-stimulating factors. Therefore, understanding the structure-function relationship of LRRC8A, exploring its physiological role in immunity, assessing its efficacy in treating diseases, and advancing the development of compounds that regulate its activity are important research frontiers. This review emphasized the emerging field of LRRC8A, outlined its structure and function, and summarized its role in immune cell development and immune cell-mediated antiviral and antitumor effects. Additionally, it explored the potential of LRRC8A as an immunotherapeutic target, offering insights into resolving persistent challenges and future research directions.
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Affiliation(s)
- Yaohua Hu
- Division of Cancer Biology, Laboratory Animal Center, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
- Department of Pathology, Affiliated Hospital of Yan'an University, Yanan, Shaanxi 716000, China
| | - Jing Qin
- Division of Cancer Biology, Laboratory Animal Center, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Yifan Ma
- Division of Cancer Biology, Laboratory Animal Center, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
- Gansu University of Traditional Chinese Medicine, Lanzhou 730030, China
| | - Runze Yang
- Division of Cancer Biology, Laboratory Animal Center, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
- Gansu University of Traditional Chinese Medicine, Lanzhou 730030, China
| | - Xinyu Liu
- Division of Cancer Biology, Laboratory Animal Center, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
- School of Basic Medical Sciences, Medical College of Yan'an University, 580 Bao-Ta Street, Yanan, Shaanxi 716000, China
| | - Changhong Shi
- Division of Cancer Biology, Laboratory Animal Center, The Fourth Military Medical University, Xi'an, Shaanxi 710032, China
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2
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Okada Y. Physiology of the volume-sensitive/regulatory anion channel VSOR/VRAC: part 2: its activation mechanisms and essential roles in organic signal release. J Physiol Sci 2024; 74:34. [PMID: 38877402 PMCID: PMC11177392 DOI: 10.1186/s12576-024-00926-3] [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: 05/05/2024] [Accepted: 06/01/2024] [Indexed: 06/16/2024]
Abstract
The volume-sensitive outwardly rectifying or volume-regulated anion channel, VSOR/VRAC, which was discovered in 1988, is expressed in most vertebrate cell types, and is essentially involved in cell volume regulation after swelling and in the induction of cell death. This series of review articles describes what is already known and what remains to be uncovered about the functional and molecular properties as well as the physiological and pathophysiological roles of VSOR/VRAC. This Part 2 review article describes, from the physiological and pathophysiological standpoints, first the pivotal roles of VSOR/VRAC in the release of autocrine/paracrine organic signal molecules, such as glutamate, ATP, glutathione, cGAMP, and itaconate, as well as second the swelling-independent and -dependent activation mechanisms of VSOR/VRAC. Since the pore size of VSOR/VRAC has now well been evaluated by electrophysiological and 3D-structural methods, the signal-releasing activity of VSOR/VRAC is here discussed by comparing the molecular sizes of these organic signals to the channel pore size. Swelling-independent activation mechanisms include a physicochemical one caused by the reduction of intracellular ionic strength and a biochemical one caused by oxidation due to stimulation by receptor agonists or apoptosis inducers. Because some organic substances released via VSOR/VRAC upon cell swelling can trigger or augment VSOR/VRAC activation in an autocrine fashion, swelling-dependent activation mechanisms are to be divided into two phases: the first phase induced by cell swelling per se and the second phase caused by receptor stimulation by released organic signals.
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Affiliation(s)
- Yasunobu Okada
- National Institute for Physiological Sciences (NIPS), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan.
- Department of Integrative Physiology, Graduate School of Medicine, Akita University, Akita, Japan.
- Department of Physiology, School of Medicine, Aichi Medical University, Nagakute, Japan.
- Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa, Japan.
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3
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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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4
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Liu H, Polovitskaya MM, Yang L, Li M, Li H, Han Z, Wu J, Zhang Q, Jentsch TJ, Liao J. Structural insights into anion selectivity and activation mechanism of LRRC8 volume-regulated anion channels. Cell Rep 2023; 42:112926. [PMID: 37543949 PMCID: PMC10480491 DOI: 10.1016/j.celrep.2023.112926] [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: 12/29/2022] [Revised: 06/12/2023] [Accepted: 07/18/2023] [Indexed: 08/08/2023] Open
Abstract
Volume-regulated anion channels (VRACs) are hexamers of LRRC8 proteins that are crucial for cell volume regulation. N termini (NTs) of the obligatory LRRC8A subunit modulate VRACs activation and ion selectivity, but the underlying mechanisms remain poorly understood. Here, we report a 2.8-Å cryo-electron microscopy structure of human LRRC8A that displays well-resolved NTs. Amino-terminal halves of NTs fold back into the pore and constrict the permeation path, thereby determining ion selectivity together with an extracellular selectivity filter with which it works in series. They also interact with pore-surrounding helices and support their compact arrangement. The C-terminal halves of NTs interact with intracellular loops that are crucial for channel activation. Molecular dynamics simulations indicate that low ionic strength increases NT mobility and expands the radial distance between pore-surrounding helices. Our work suggests an unusual pore architecture with two selectivity filters in series and a mechanism for VRAC activation by cell swelling.
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Affiliation(s)
- Heng Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Maya M Polovitskaya
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), 13125 Berlin, Germany
| | - Linlin Yang
- Department of Pharmacology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 45001, China.
| | - Meiling Li
- Department of Pharmacology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 45001, China
| | - Hongyue Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhen Han
- Department of Pharmacology, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan 45001, China
| | - Jianguo Wu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiansen Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, School of Life Sciences, East China Normal University, Shanghai, China.
| | - Thomas J Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), 13125 Berlin, Germany; Cluster of Excellence NeuroCure, Charité Universitätsmedizin Berlin, Berlin, Germany.
| | - Jun Liao
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai 200031, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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5
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Liu T, Li Y, Wang D, Stauber T, Zhao J. Trends in volume-regulated anion channel (VRAC) research: visualization and bibliometric analysis from 2014 to 2022. Front Pharmacol 2023; 14:1234885. [PMID: 37538172 PMCID: PMC10394876 DOI: 10.3389/fphar.2023.1234885] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 07/10/2023] [Indexed: 08/05/2023] Open
Abstract
Objective: In this study, we utilized bibliometric methods to assess the worldwide scientific output and identify hotspots related to the research on the volume-regulated anion channel (VRAC) from 2014 to 2022. Methods: From Web of Science, we obtained studies related to VRAC published from 2014 to 2022. To analyzed the data, we utilized VOSviewer, a tool for visualizing network, to create networks based on the collaboration between countries, institutions, and authors. Additionally, we performed an analysis of journal co-citation, document citation, and co-occurrence of keywords. Furthermore, we employed CiteSpace (6.1. R6 Advanced) to analyzed keywords and co-cited references with the strongest burst. Results: The final analysis included a total of 278 related articles and reviews, covering the period from 2014 to 2022. The United States emerged as the leading country contributing to this field, while the University of Copenhagen stood out as the most prominent institution. The author with most publications and most citations was Thomas J. Jentsch. Among the cited references, the article by Voss et al. published in Science (2014) gained significant attention for its identification of LRRC8 heteromers as a crucial component of the volume-regulated anion channel VRAC. Pflügers Archiv European Journal of Physiology and Journal of Physiology-London were the leading journals in terms of the quantity of associated articles and citations. Through the analysis of keyword co-occurrence, it was discovered that VRAC is involved in various physiological processes including cell growth, migration, apoptosis, swelling, and myogenesis, as well as anion and organic osmolyte transport including chloride, taurine, glutamate and ATP. VRAC is also associated with related ion channels such as TMEM16A, TMEM16F, pannexin, and CFTR, and associated with various diseases including epilepsy, leukodystrophy, atherosclerosis, hypertension, cerebral edema, stroke, and different types of cancer including gastric cancer, glioblastoma and hepatocellular carcinoma. Furthermore, VRAC is involved in anti-tumor drug resistance by regulating the uptake of platinum-based drugs and temozolomide. Additionally, VRAC has been studied in the context of pharmacology involving DCPIB and flavonoids. Conclusion: The aim of this bibliometric analysis is to provide an overall perspective for research on VRAC. VRAC has become a topic of increasing interest, and our analysis shows that it continues to be a prominent area. This study offers insights into the investigation of VRAC channel and may guide researchers in identifying new directions for future research.
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Affiliation(s)
- Tianbao Liu
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
- Shandong Institute of Endocrine and Metabolic Disease, Jinan, Shandong, China
| | - Yin Li
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Shandong Provincial Hospital, Jinan, Shandong, China
| | - Dawei Wang
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
- Shandong Institute of Endocrine and Metabolic Disease, Jinan, Shandong, China
- Department of Endocrinology, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China
| | - Tobias Stauber
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Jiajun Zhao
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
- Shandong Institute of Endocrine and Metabolic Disease, Jinan, Shandong, China
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6
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Kern DM, Bleier J, Mukherjee S, Hill JM, Kossiakoff AA, Isacoff EY, Brohawn SG. Structural basis for assembly and lipid-mediated gating of LRRC8A:C volume-regulated anion channels. Nat Struct Mol Biol 2023:10.1038/s41594-023-00944-6. [PMID: 36928458 DOI: 10.1038/s41594-023-00944-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/22/2023] [Indexed: 03/18/2023]
Abstract
Leucine-rich repeat-containing protein 8 (LRRC8) family members form volume-regulated anion channels activated by hypoosmotic cell swelling. LRRC8 channels are ubiquitously expressed in vertebrate cells as heteromeric assemblies of LRRC8A (SWELL1) and LRRC8B-E subunits. Channels of different subunit composition have distinct properties that explain the functional diversity of LRRC8 currents across cell types. However, the basis for heteromeric LRRC8 channel assembly and function is unknown. Here we leverage a fiducial-tagging strategy to determine single-particle cryo-EM structures of heterohexameric LRRC8A:C channels in multiple conformations. Compared to homomers, LRRC8A:C channels show pronounced differences in architecture due to heterotypic LRR interactions that displace subunits away from the conduction axis and poise the channel for activation. Structures and functional studies further reveal that lipids embedded in the channel pore block ion conduction in the closed state. These results provide insight into determinants for heteromeric LRRC8 channel assembly, activity and gating by lipids.
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Affiliation(s)
- David M Kern
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, USA.,Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA.,California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, USA
| | - Julia Bleier
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
| | - Somnath Mukherjee
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA
| | - Jennifer M Hill
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, USA
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL, USA.,Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, USA
| | - Ehud Y Isacoff
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, USA.,Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA.,California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, USA
| | - Stephen G Brohawn
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, USA. .,Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA. .,California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA, USA.
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7
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Vandorpe DH, Heneghan JF, Waitzman JS, McCarthy GM, Blasio A, Magraner JM, Donovan OG, Schaller LB, Shah SS, Subramanian B, Riella CV, Friedman DJ, Pollak MR, Alper SL. Apolipoprotein L1 (APOL1) cation current in HEK-293 cells and in human podocytes. Pflugers Arch 2023; 475:323-341. [PMID: 36449077 DOI: 10.1007/s00424-022-02767-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/14/2022] [Accepted: 10/25/2022] [Indexed: 12/05/2022]
Abstract
Two heterozygous missense variants (G1 and G2) of Apolipoprotein L1 (APOL1) found in individuals of recent African ancestry can attenuate the severity of infection by some forms of Trypanosoma brucei. However, these two variants within a broader African haplotype also increase the risk of kidney disease in Americans of African descent. Although overexpression of either variant G1 or G2 causes multiple pathogenic changes in cultured cells and transgenic mouse models, the mechanism(s) promoting kidney disease remain unclear. Human serum APOL1 kills trypanosomes through its cation channel activity, and cation channel activity of recombinant APOL1 has been reconstituted in lipid bilayers and proteoliposomes. Although APOL1 overexpression increases whole cell cation currents in HEK-293 cells, the ion channel activity of APOL1 has not been assessed in glomerular podocytes, the major site of APOL1-associated kidney diseases. We characterize APOL1-associated whole cell and on-cell cation currents in HEK-293 T-Rex cells and demonstrate partial inhibition of currents by anti-APOL antibodies. We detect in primary human podocytes a similar cation current inducible by interferon-γ (IFNγ) and sensitive to inhibition by anti-APOL antibody as well as by a fragment of T. brucei Serum Resistance-Associated protein (SRA). CRISPR knockout of APOL1 in human primary podocytes abrogates the IFNγ-induced, antibody-sensitive current. Our novel characterization in HEK-293 cells of heterologous APOL1-associated cation conductance inhibited by anti-APOL antibody and our documentation in primary human glomerular podocytes of endogenous IFNγ-stimulated, APOL1-mediated, SRA and anti-APOL-sensitive ion channel activity together support APOL1-mediated channel activity as a therapeutic target for treatment of APOL1-associated kidney diseases.
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Affiliation(s)
- David H Vandorpe
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - John F Heneghan
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Department of Pathology, Brigham and Women's Hospital, Boston, MA, 02215, USA
| | - Joshua S Waitzman
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Gizelle M McCarthy
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Vertex Pharmaceuticals, Boston, MA, 02210, USA
| | - Angelo Blasio
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Vertex Pharmaceuticals, Boston, MA, 02210, USA
| | - Jose M Magraner
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,, San Diego, CA, USA
| | - Olivia G Donovan
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA
| | - Lena B Schaller
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Ludwig-Maximilians-Universitaet, 80336, Munich, Germany
| | - Shrijal S Shah
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Chroma Medicine, Cambridge, MA, 02142, USA
| | - Balajikarthick Subramanian
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Cristian V Riella
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - David J Friedman
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA.,Broad Institute of Harvard and MIT, Cambridge, MA, 02139, USA
| | - Martin R Pollak
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA.,Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA.,Broad Institute of Harvard and MIT, Cambridge, MA, 02139, USA
| | - Seth L Alper
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center RN380F, 99 Brookline Ave, Boston, MA, 02215, USA. .,Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA. .,Broad Institute of Harvard and MIT, Cambridge, MA, 02139, USA.
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8
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Rutz S, Deneka D, Dittmann A, Sawicka M, Dutzler R. Structure of a volume-regulated heteromeric LRRC8A/C channel. Nat Struct Mol Biol 2023; 30:52-61. [PMID: 36522427 PMCID: PMC9851909 DOI: 10.1038/s41594-022-00899-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 11/15/2022] [Indexed: 12/23/2022]
Abstract
Volume-regulated anion channels (VRACs) participate in the cellular response to osmotic swelling. These membrane proteins consist of heteromeric assemblies of LRRC8 subunits, whose compositions determine permeation properties. Although structures of the obligatory LRRC8A, also referred to as SWELL1, have previously defined the architecture of VRACs, the organization of heteromeric channels has remained elusive. Here we have addressed this question by the structural characterization of murine LRRC8A/C channels. Like LRRC8A, these proteins assemble as hexamers. Despite 12 possible arrangements, we find a predominant organization with an A:C ratio of two. In this assembly, four LRRC8A subunits cluster in their preferred conformation observed in homomers, as pairs of closely interacting proteins that stabilize a closed state of the channel. In contrast, the two interacting LRRC8C subunits show a larger flexibility, underlining their role in the destabilization of the tightly packed A subunits, thereby enhancing the activation properties of the protein.
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Affiliation(s)
- Sonja Rutz
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | - Dawid Deneka
- Department of Biochemistry, University of Zurich, Zurich, Switzerland
| | | | - Marta Sawicka
- Department of Biochemistry, University of Zurich, Zurich, Switzerland.
| | - Raimund Dutzler
- Department of Biochemistry, University of Zurich, Zurich, Switzerland.
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9
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Ghouli MR, Fiacco TA, Binder DK. Structure-function relationships of the LRRC8 subunits and subdomains of the volume-regulated anion channel (VRAC). Front Cell Neurosci 2022; 16:962714. [PMID: 36035259 PMCID: PMC9399500 DOI: 10.3389/fncel.2022.962714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/18/2022] [Indexed: 11/19/2022] Open
Abstract
Volume Regulated Anion Channels (VRAC) are critical contributors to cell volume homeostasis and are expressed ubiquitously in all vertebrate cells. VRAC sense increases in cell volume, and act to return cells to baseline volume in a process known as regulatory volume decrease (RVD) through the efflux of anions and organic osmolytes. This review will highlight seminal studies that elucidated the role of VRAC in RVD, their characteristics as a function of subunit specificity, and their clinical relevance in physiology and pathology. VRAC are also known as volume-sensitive outward rectifiers (VSOR) and volume-sensitive organic osmolyte/anion channels (VSOAC). In this review, the term VRAC will be used to refer to this family of channels.
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Affiliation(s)
- Manolia R. Ghouli
- Division of Biomedical Sciences, School of Medicine, University of California–Riverside, Riverside, CA, United States
| | - Todd A. Fiacco
- Department of Cell Biology and Neuroscience, Center for Glial-Neuronal Interactions, University of California–Riverside, Riverside, CA, United States
| | - Devin K. Binder
- Division of Biomedical Sciences, School of Medicine, University of California–Riverside, Riverside, CA, United States
- *Correspondence: Devin K. Binder
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10
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Sawicka M, Dutzler R. Regulators of cell volume: The structural and functional properties of anion channels of the LRRC8 family. Curr Opin Struct Biol 2022; 74:102382. [DOI: 10.1016/j.sbi.2022.102382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 11/03/2022]
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11
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Kasuya G, Nureki O. Recent Advances in the Structural Biology of the Volume-Regulated Anion Channel LRRC8. Front Pharmacol 2022; 13:896532. [PMID: 35645818 PMCID: PMC9130832 DOI: 10.3389/fphar.2022.896532] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 04/25/2022] [Indexed: 01/23/2023] Open
Abstract
Members of the leucine-rich repeat-containing 8 (LRRC8) protein family, composed of five LRRC8A-E isoforms, are pore-forming components of the volume-regulated anion channel (VRAC), which is activated by cell swelling and releases chloride ions (Cl−) or other osmolytes to counteract cell swelling. Although the LRRC8 protein family was identified as the molecular entity of VRAC only in 2014, due to recent advances in cryo-electron microscopy (cryo-EM), various LRRC8 structures, including homo-hexameric LRRC8A and LRRC8D structures, as well as inhibitor-bound and synthetic single-domain antibody-bound homo-hexameric LRRC8A structures, have been reported, thus extending our understanding of the molecular mechanisms of this protein family. In this review, we describe the important features of LRRC8 provided by these structures, particularly the overall architectures, and the suggested mechanisms underlying pore inhibition and allosteric modulation by targeting the intracellular leucine-rich repeat (LRR) domain.
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Affiliation(s)
- Go Kasuya
- Division of Integrative Physiology, Department of Physiology, Jichi Medical University, Shimotsuke, Japan
- *Correspondence: Go Kasuya, ; Osamu Nureki,
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- *Correspondence: Go Kasuya, ; Osamu Nureki,
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Tee WV, Wah Tan Z, Guarnera E, Berezovsky IN. Conservation and diversity in allosteric fingerprints of proteins for evolutionary-inspired engineering and design. J Mol Biol 2022; 434:167577. [PMID: 35395233 DOI: 10.1016/j.jmb.2022.167577] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 03/30/2022] [Accepted: 03/30/2022] [Indexed: 11/26/2022]
Abstract
Hand-in-hand work of physics and evolution delivered protein universe with diversity of forms, sizes, and functions. Pervasiveness and advantageous traits of allostery made it an important component of the protein function regulation, calling for thorough investigation of its structural determinants and evolution. Learning directly from nature, we explored here allosteric communication in several major folds and repeat proteins, including α/β and β-barrels, β-propellers, Ig-like fold, ankyrin and α/β leucine-rich repeat proteins, which provide structural platforms for many different enzymatic and signalling functions. We obtained a picture of conserved allosteric communication characteristic in different fold types, modifications of the structure-driven signalling patterns via sequence-determined divergence to specific functions, as well as emergence and potential diversification of allosteric regulation in multi-domain proteins and oligomeric assemblies. Our observations will be instrumental in facilitating the engineering and de novo design of proteins with allosterically regulated functions, including development of therapeutic biologics. In particular, results described here may guide the identification of the optimal structural platforms (e.g. fold type, size, and oligomerization states) and the types of diversifications/perturbations, such as mutations, effector binding, and order-disorder transition. The tunable allosteric linkage across distant regions can be used as a pivotal component in the design/engineering of modular biological systems beyond the traditional scaffolding function.
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Affiliation(s)
- Wei-Ven Tee
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01, Matrix, Singapore 138671
| | - Zhen Wah Tan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01, Matrix, Singapore 138671
| | - Enrico Guarnera
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01, Matrix, Singapore 138671
| | - Igor N Berezovsky
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), 30 Biopolis Street, #07-01, Matrix, Singapore 138671; Department of Biological Sciences (DBS), National University of Singapore (NUS), 8 Medical Drive, Singapore 117597.
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Okada Y, Sabirov RZ, Merzlyak PG, Numata T, Sato-Numata K. Properties, Structures, and Physiological Roles of Three Types of Anion Channels Molecularly Identified in the 2010's. Front Physiol 2022; 12:805148. [PMID: 35002778 PMCID: PMC8733619 DOI: 10.3389/fphys.2021.805148] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/06/2021] [Indexed: 11/24/2022] Open
Abstract
Molecular identification was, at last, successfully accomplished for three types of anion channels that are all implicated in cell volume regulation/dysregulation. LRRC8A plus LRRC8C/D/E, SLCO2A1, and TMEM206 were shown to be the core or pore-forming molecules of the volume-sensitive outwardly rectifying anion channel (VSOR) also called the volume-regulated anion channel (VRAC), the large-conductance maxi-anion channel (Maxi-Cl), and the acid-sensitive outwardly rectifying anion channel (ASOR) also called the proton-activated anion channel (PAC) in 2014, 2017, and 2019, respectively. More recently in 2020 and 2021, we have identified the S100A10-annexin A2 complex and TRPM7 as the regulatory proteins for Maxi-Cl and VSOR/VRAC, respectively. In this review article, we summarize their biophysical and structural properties as well as their physiological roles by comparing with each other on the basis of their molecular insights. We also point out unsolved important issues to be elucidated soon in the future.
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Affiliation(s)
- Yasunobu Okada
- National Institute for Physiological Sciences (NIPS), Okazaki, Japan.,Department of Physiology, School of Medicine, Aichi Medical University, Nagakute, Japan.,Department of Physiology, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Cardiovascular Research Institute, Yokohama City University, Yokohama, Japan
| | - Ravshan Z Sabirov
- Laboratory of Molecular Physiology, Institute of Biophysics and Biochemistry, National University of Uzbekistan, Tashkent, Uzbekistan
| | - Petr G Merzlyak
- Laboratory of Molecular Physiology, Institute of Biophysics and Biochemistry, National University of Uzbekistan, Tashkent, Uzbekistan
| | - Tomohiro Numata
- Department of Integrative Physiology, Graduate School of Medicine, Akita University, Akita, Japan
| | - Kaori Sato-Numata
- Department of Integrative Physiology, Graduate School of Medicine, Akita University, Akita, Japan.,Japan Society for the Promotion of Science, Tokyo, Japan
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