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Manori B, Vaknin A, Vaňková P, Nitzan A, Zaidel-Bar R, Man P, Giladi M, Haitin Y. Chloride intracellular channel (CLIC) proteins function as fusogens. Nat Commun 2024; 15:2085. [PMID: 38453905 PMCID: PMC10920813 DOI: 10.1038/s41467-024-46301-z] [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: 08/27/2023] [Accepted: 02/19/2024] [Indexed: 03/09/2024] Open
Abstract
Chloride Intracellular Channel (CLIC) family members uniquely transition between soluble and membrane-associated conformations. Despite decades of extensive functional and structural studies, CLICs' function as ion channels remains debated, rendering our understanding of their physiological role incomplete. Here, we expose the function of CLIC5 as a fusogen. We demonstrate that purified CLIC5 directly interacts with the membrane and induces fusion, as reflected by increased liposomal diameter and lipid and content mixing between liposomes. Moreover, we show that this activity is facilitated by acidic pH, a known trigger for CLICs' transition to a membrane-associated conformation, and that increased exposure of the hydrophobic inter-domain interface is crucial for this process. Finally, mutation of a conserved hydrophobic interfacial residue diminishes the fusogenic activity of CLIC5 in vitro and impairs excretory canal extension in C. elegans in vivo. Together, our results unravel the long-sought physiological role of these enigmatic proteins.
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Grants
- 1721/16 Israel Science Foundation (ISF)
- 1653/21 Israel Science Foundation (ISF)
- 3308/20 Israel Science Foundation (ISF)
- 01214 Israel Cancer Research Fund (Israel Cancer Research Fund, Inc.)
- 19202 Israel Cancer Research Fund (Israel Cancer Research Fund, Inc.)
- 20230029 Israel Cancer Association (ICA)
- CZ.1.05/1.1.00/02.0109 Ministerstvo školstva, vedy, výskumu a športu Slovenskej republiky (Ministry of Education, Science, Research and Sport of the Slovak Republic)
- 731077 EC | Horizon 2020 Framework Programme (EU Framework Programme for Research and Innovation H2020)
- The Claire and Amedee Maratier Institute for the Study of Blindness and Visual Disorders, Faculty of Medicine, Tel-Aviv University.
- The Czech Infrastructure for Integrative Structural Biology (CIISB) grant (LM2023042).
- The Kahn Foundation's Orion project, Tel Aviv Sourasky Medical Center, Israel. The Claire and Amedee Maratier Institute for the Study of Blindness and Visual Disorders, Faculty of Medicine, Tel-Aviv University.
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Affiliation(s)
- Bar Manori
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 6997801, Israel
| | - Alisa Vaknin
- School of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Pavla Vaňková
- Institute of Biotechnology of the Czech Academy of Sciences, Division BioCeV, Prumyslova 595, 252 50, Vestec, Czech Republic
| | - Anat Nitzan
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 6997801, Israel
| | - Ronen Zaidel-Bar
- Department of Cell and Developmental Biology, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 6997801, Israel
| | - Petr Man
- Institute of Microbiology of the Czech Academy of Sciences, Division BioCeV, Prumyslova 595, 252 50, Vestec, Czech Republic
| | - Moshe Giladi
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 6997801, Israel.
- Tel Aviv Sourasky Medical Center, Tel Aviv, 6423906, Israel.
| | - Yoni Haitin
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel-Aviv University, Tel-Aviv, 6997801, Israel.
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel.
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2
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Porter LL. Predictable fold switching by the SARS-CoV-2 protein ORF9b. Protein Sci 2021; 30:1723-1729. [PMID: 33934422 PMCID: PMC8242659 DOI: 10.1002/pro.4097] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/24/2021] [Accepted: 04/27/2021] [Indexed: 12/27/2022]
Abstract
Extant fold-switching proteins remodel their secondary structures and change their functions in response to environmental stimuli. These shapeshifting proteins regulate biological processes and are associated with a number of diseases, including tuberculosis, cancer, Alzheimer's, and autoimmune disorders. Thus, predictive methods are needed to identify more fold-switching proteins, especially since all naturally occurring instances have been discovered by chance. In response to this need, two high-throughput predictive methods have recently been developed. Here we test them on ORF9b, a newly discovered fold switcher and potential therapeutic target from the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Promisingly, both methods correctly indicate that ORF9b switches folds. We then tested the same two methods on ORF9b1, the ORF9b homolog from SARS-CoV-1. Again, both methods predict that ORF9b1 switches folds, a finding consistent with experimental binding studies. Together, these results (a) demonstrate that protein fold switching can be predicted using high-throughput computational approaches and (b) suggest that fold switching might be a general characteristic of ORF9b homologs.
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Affiliation(s)
- Lauren L. Porter
- National Library of MedicineNational Center for Biotechnology Information, National Institutes of HealthBethesdaMarylandUSA
- National Heart, Lung, and Blood InstituteBiochemistry and Biophysics Center, National Institutes of HealthBethesdaMarylandUSA
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3
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Ferofontov A, Vankova P, Man P, Giladi M, Haitin Y. Conserved cysteine dioxidation enhances membrane interaction of human Cl - intracellular channel 5. FASEB J 2020; 34:9925-9940. [PMID: 32725932 DOI: 10.1096/fj.202000399r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 04/21/2020] [Accepted: 04/30/2020] [Indexed: 11/11/2022]
Abstract
The human chloride intracellular channel (hCLIC) family is thought to transition between globular and membrane-associated forms by exposure of a hydrophobic surface. However, the molecular identity of this surface, and the triggering events leading to its exposure, remain elusive. Here, by combining biochemical and structural approaches, together with mass spectrometry (MS) analyses, we show that hCLIC5 is inherently flexible. X-ray crystallography revealed the existence of a globular conformation, while small-angle X-ray scattering showed additional elongated forms consisting of exposure of the conserved hydrophobic inter-domain interface to the bulk phase. Tryptophan fluorescence measurements demonstrated that the transition to the membrane-associated form is enhanced by the presence of oxidative environment and lipids. Using MS, we identified a dose-dependent oxidation of a highly conserved cysteine residue, known to play a key role in the structurally related omega-class of glutathione-S-transferases. Hydrogen/deuterium exchange MS analysis revealed that oxidation of this cysteine facilitates the exposure of the conserved hydrophobic inter-domain interface. Together, our results pinpoint an oxidation of a specific cysteine residue as a triggering mechanism initializing the molecular commitment for membrane interaction in the CLIC family.
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Affiliation(s)
- Alisa Ferofontov
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Pavla Vankova
- Division BioCeV, Institute of Microbiology of the Czech Academy of Sciences, Vestec, Czech Republic.,Department of Biochemistry, Faculty of Science, Charles University, Prague, Czech Republic
| | - Petr Man
- Division BioCeV, Institute of Microbiology of the Czech Academy of Sciences, Vestec, Czech Republic
| | - Moshe Giladi
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Yoni Haitin
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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4
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Kawai S, Fujii T, Shimizu T, Sukegawa K, Hashimoto I, Okumura T, Nagata T, Sakai H, Fujii T. Pathophysiological properties of CLIC3 chloride channel in human gastric cancer cells. J Physiol Sci 2020; 70:15. [PMID: 32066374 PMCID: PMC7026216 DOI: 10.1186/s12576-020-00740-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 02/04/2020] [Indexed: 11/24/2022]
Abstract
Pathophysiological functions of chloride intracellular channel protein 3 (CLIC3) in human gastric cancer have been unclear. In the tissue microarray analysis using 107 gastric cancer specimens, CLIC3 expression was negatively correlated with pathological tumor depth, and the patients with lower expression of CLIC3 exhibited poorer prognosis. CLIC3 was expressed in the plasma membrane of cancer cells in the tissue. CLIC3 expression was also found in a human gastric cancer cell line (MKN7). In whole-cell patch-clamp recordings of the cells expressing CLIC3, NPPB-sensitive outwardly rectifying Cl− currents were observed. Cell proliferation was significantly accelerated by knockdown of CLIC3 in MKN7 cells. On the other hand, the proliferation was attenuated by exogenous CLIC3 expression in human gastric cancer cells (KATOIII and NUGC-4) in which endogenous CLIC3 expression is negligible. Our results suggest that CLIC3 functions as a Cl− channel in the plasma membrane of gastric cancer cells and that decreased expression of CLIC3 results in unfavorable prognosis of gastric cancer patients.
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Affiliation(s)
- Shunsuke Kawai
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Takuto Fujii
- Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Takahiro Shimizu
- Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Kenta Sukegawa
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Isaya Hashimoto
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Tomoyuki Okumura
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Takuya Nagata
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Hideki Sakai
- Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
| | - Tsutomu Fujii
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
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5
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Ferofontov A, Strulovich R, Marom M, Giladi M, Haitin Y. Inherent flexibility of CLIC6 revealed by crystallographic and solution studies. Sci Rep 2018; 8:6882. [PMID: 29720717 PMCID: PMC5931990 DOI: 10.1038/s41598-018-25231-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 04/16/2018] [Indexed: 12/22/2022] Open
Abstract
Chloride intracellular channels (CLICs) are a family of unique proteins, that were suggested to adopt both soluble and membrane-associated forms. Moreover, following this unusual metamorphic change, CLICs were shown to incorporate into membranes and mediate ion conduction in vitro, suggesting multimerization upon membrane insertion. Here, we present a 1.8 Å resolution crystal structure of the CLIC domain of mouse CLIC6 (mCLIC6). The structure reveals a monomeric arrangement and shows a high degree of structural conservation with other CLICs. Small-angle X-ray scattering (SAXS) analysis of mCLIC6 demonstrated that the overall solution structure is similar to the crystallographic conformation. Strikingly, further analysis of the SAXS data using ensemble optimization method unveiled additional elongated conformations, elucidating high structural plasticity as an inherent property of the protein. Moreover, structure-guided perturbation of the inter-domain interface by mutagenesis resulted in a population shift towards elongated conformations of mCLIC6. Additionally, we demonstrate that oxidative conditions induce an increase in mCLIC6 hydrophobicity along with mild oligomerization, which was enhanced by the presence of membrane mimetics. Together, these results provide mechanistic insights into the metamorphic nature of mCLIC6.
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Affiliation(s)
- Alisa Ferofontov
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, 6997801, Israel
| | - Roi Strulovich
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, 6997801, Israel
| | - Milit Marom
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, 6997801, Israel
| | - Moshe Giladi
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, 6997801, Israel
| | - Yoni Haitin
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, 6997801, Israel. .,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel.
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6
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Liang J, Shaulov Y, Savage-Dunn C, Boissinot S, Hoque T. Chloride intracellular channel proteins respond to heat stress in Caenorhabditis elegans. PLoS One 2017; 12:e0184308. [PMID: 28886120 PMCID: PMC5590911 DOI: 10.1371/journal.pone.0184308] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/21/2017] [Indexed: 01/05/2023] Open
Abstract
Chloride intracellular channel proteins (CLICs) are multi-functional proteins that are expressed in various cell types and differ in their subcellular location. Two CLIC homologs, EXL-1 (excretory canal abnormal like-1) and EXC-4 (excretory canal abnormal- 4), are encoded in the Caenorhabditis elegans genome, providing an excellent model to study the functional diversification of CLIC proteins. EXC-4 functions in excretory canal formation during normal animal development. However, to date, the physiological function of EXL-1 remains largely unknown. In this study, we demonstrate that EXL-1 responds specifically to heat stress and translocates from the cytoplasm to the nucleus in intestinal cells and body wall muscle cells under heat shock. In contrast, we do not observe EXC-4 nuclear translocation under heat shock. Full protein sequence analysis shows that EXL-1 bears a non-classic nuclear localization signal (NLS) that EXC-4 is lacking. All mammalian CLIC members have a nuclear localization signal, with the exception of CLIC3. Our phylogenetic analysis of the CLIC gene families across various animal species demonstrates that the duplication of CLICs in protostomes and deuterostomes occurred independently and that the NLS was subsequently lost in amniotes and nematodes, suggesting convergent evolution. We also observe that EXL-1 nuclear translocation occurs in a timely ordered manner in the intestine, from posterior to anterior regions. Finally, we find that exl-1 loss of function mutants are more susceptible to heat stress than wild-type animals, demonstrating functional relevance of the nuclear translocation. This research provides the first link between CLICs and environmental heat stress. We propose that C. elegans CLICs evolved to achieve different physiological functions through subcellular localization change and spatial separation in response to external or internal signals.
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Affiliation(s)
- Jun Liang
- Department of Science, Borough of Manhattan Community College / CUNY, New York, New York, United States of America
- * E-mail:
| | - Yakov Shaulov
- Department of Biology, Queens College, CUNY, Flushing, New York, United States of America
| | - Cathy Savage-Dunn
- Department of Biology, Queens College, CUNY, Flushing, New York, United States of America
- Biology PhD Program and Biochemistry PhD Program, the Graduate Center, New York, New York, United States of America
| | - Stephane Boissinot
- New York University Abu Dhabi, Saadiyat Island campus, Abu Dhabi, United Arab Emirates
| | - Tasmia Hoque
- Department of Science, Borough of Manhattan Community College / CUNY, New York, New York, United States of America
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7
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Identification and Characterization of a Bacterial Homolog of Chloride Intracellular Channel (CLIC) Protein. Sci Rep 2017; 7:8500. [PMID: 28819106 PMCID: PMC5561075 DOI: 10.1038/s41598-017-08742-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/17/2017] [Indexed: 11/25/2022] Open
Abstract
Chloride intracellular channels (CLIC) are non-classical ion channels lacking a signal sequence for membrane targeting. In eukaryotes, they are implicated in cell volume regulation, acidification, and cell cycle. CLICs resemble the omega class of Glutathione S-transferases (GST), yet differ from them in their ability to form ion channels. They are ubiquitously found in eukaryotes but no prokaryotic homolog has been characterized. We found that indanyloxyacetic acid-94 (IAA-94), a blocker of CLICs, delays the growth of Escherichia coli. In silico analysis showed that the E. coli stringent starvation protein A (SspA) shares sequence and structural homology with CLICs. Similar to CLICs, SspA lacks a signal sequence but contains an omega GST fold. Electrophysiological analysis revealed that SspA auto-inserts into lipid bilayers and forms IAA-94-sensitive ion channels. Substituting the ubiquitously conserved residue leucine 29 to alanine in the pore-forming region increased its single-channel conductance. SspA is essential for cell survival during acid-induced stress, and we found that acidic pH increases the open probability of SspA. Further, IAA-94 delayed the growth of wild-type but not sspA null mutant E. coli. Our results for the first time show that CLIC-like proteins exist in bacteria in the form of SspA, forming functional ion channels.
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8
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Armstrong SD, Xia D, Bah GS, Krishna R, Ngangyung HF, LaCourse EJ, McSorley HJ, Kengne-Ouafo JA, Chounna-Ndongmo PW, Wanji S, Enyong PA, Taylor DW, Blaxter ML, Wastling JM, Tanya VN, Makepeace BL. Stage-specific Proteomes from Onchocerca ochengi, Sister Species of the Human River Blindness Parasite, Uncover Adaptations to a Nodular Lifestyle. Mol Cell Proteomics 2016; 15:2554-75. [PMID: 27226403 PMCID: PMC4974336 DOI: 10.1074/mcp.m115.055640] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 04/30/2016] [Indexed: 12/13/2022] Open
Abstract
Despite 40 years of control efforts, onchocerciasis (river blindness) remains one of the most important neglected tropical diseases, with 17 million people affected. The etiological agent, Onchocerca volvulus, is a filarial nematode with a complex lifecycle involving several distinct stages in the definitive host and blackfly vector. The challenges of obtaining sufficient material have prevented high-throughput studies and the development of novel strategies for disease control and diagnosis. Here, we utilize the closest relative of O. volvulus, the bovine parasite Onchocerca ochengi, to compare stage-specific proteomes and host-parasite interactions within the secretome. We identified a total of 4260 unique O. ochengi proteins from adult males and females, infective larvae, intrauterine microfilariae, and fluid from intradermal nodules. In addition, 135 proteins were detected from the obligate Wolbachia symbiont. Observed protein families that were enriched in all whole body extracts relative to the complete search database included immunoglobulin-domain proteins, whereas redox and detoxification enzymes and proteins involved in intracellular transport displayed stage-specific overrepresentation. Unexpectedly, the larval stages exhibited enrichment for several mitochondrial-related protein families, including members of peptidase family M16 and proteins which mediate mitochondrial fission and fusion. Quantification of proteins across the lifecycle using the Hi-3 approach supported these qualitative analyses. In nodule fluid, we identified 94 O. ochengi secreted proteins, including homologs of transforming growth factor-β and a second member of a novel 6-ShK toxin domain family, which was originally described from a model filarial nematode (Litomosoides sigmodontis). Strikingly, the 498 bovine proteins identified in nodule fluid were strongly dominated by antimicrobial proteins, especially cathelicidins. This first high-throughput analysis of an Onchocerca spp. proteome across the lifecycle highlights its profound complexity and emphasizes the extremely close relationship between O. ochengi and O. volvulus The insights presented here provide new candidates for vaccine development, drug targeting and diagnostic biomarkers.
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Affiliation(s)
- Stuart D Armstrong
- From the ‡Institute of Infection & Global Health, University of Liverpool, Liverpool L3 5RF, UK
| | - Dong Xia
- From the ‡Institute of Infection & Global Health, University of Liverpool, Liverpool L3 5RF, UK
| | - Germanus S Bah
- §Institut de Recherche Agricole pour le Développement, Regional Centre of Wakwa, BP65 Ngaoundéré, Cameroon
| | - Ritesh Krishna
- ¶Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Henrietta F Ngangyung
- §Institut de Recherche Agricole pour le Développement, Regional Centre of Wakwa, BP65 Ngaoundéré, Cameroon
| | - E James LaCourse
- ‖Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Henry J McSorley
- **The Queens Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4JT
| | - Jonas A Kengne-Ouafo
- ‡‡Research Foundation for Tropical Diseases and Environment, PO Box 474 Buea, Cameroon
| | | | - Samuel Wanji
- ‡‡Research Foundation for Tropical Diseases and Environment, PO Box 474 Buea, Cameroon
| | - Peter A Enyong
- ‡‡Research Foundation for Tropical Diseases and Environment, PO Box 474 Buea, Cameroon; §§Tropical Medicine Research Station, Kumba, Cameroon
| | - David W Taylor
- From the ‡Institute of Infection & Global Health, University of Liverpool, Liverpool L3 5RF, UK; ¶¶Division of Pathway Medicine, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Mark L Blaxter
- ‖‖Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - Jonathan M Wastling
- From the ‡Institute of Infection & Global Health, University of Liverpool, Liverpool L3 5RF, UK; ‡‡‡The National Institute for Health Research, Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool L3 5RF, UK
| | - Vincent N Tanya
- §Institut de Recherche Agricole pour le Développement, Regional Centre of Wakwa, BP65 Ngaoundéré, Cameroon
| | - Benjamin L Makepeace
- From the ‡Institute of Infection & Global Health, University of Liverpool, Liverpool L3 5RF, UK;
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9
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Hare JE, Goodchild SC, Breit SN, Curmi PMG, Brown LJ. Interaction of Human Chloride Intracellular Channel Protein 1 (CLIC1) with Lipid Bilayers: A Fluorescence Study. Biochemistry 2016; 55:3825-33. [PMID: 27299171 DOI: 10.1021/acs.biochem.6b00080] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chloride intracellular channel protein 1 (CLIC1) is very unusual as it adopts a soluble glutathione S-transferase-like canonical fold but can also autoinsert into lipid bilayers to form an ion channel. The conversion between these forms involves a large, but reversible, structural rearrangement of the CLIC1 module. The only identified environmental triggers controlling the metamorphic transition of CLIC1 are pH and oxidation. Until now, there have been no high-resolution structural data available for the CLIC1 integral membrane state, and consequently, a limited understanding of how CLIC1 unfolds and refolds across the bilayer to form a membrane protein with ion channel activity exists. Here we show that fluorescence spectroscopy can be used to establish the interaction and position of CLIC1 in a lipid bilayer. Our method employs a fluorescence energy transfer (FRET) approach between CLIC1 and a dansyl-labeled lipid analogue to probe the CLIC1-lipid interface. Under oxidizing conditions, a strong FRET signal between the single tryptophan residue of CLIC1 (Trp35) and the dansyl-lipid analogue was detected. When considering the proportion of CLIC1 interacting with the lipid bilayer, as estimated by fluorescence quenching experiments, the FRET distance between Trp35 and the dansyl moiety on the membrane surface was determined to be ∼15 Å. This FRET-detected interaction provides direct structural evidence that CLIC1 associates with membranes. The results presented support the current model of an oxidation-driven interaction of CLIC1 with lipid bilayers and also propose a membrane anchoring role for Trp35.
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Affiliation(s)
- Joanna E Hare
- Department of Chemistry and Biomolecular Sciences, Macquarie University , Sydney, New South Wales 2109, Australia
| | - Sophia C Goodchild
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, University of Leeds , Leeds LS29JT, United Kingdom
| | - Samuel N Breit
- St Vincent's Centre for Applied Medical Research, St Vincent's Hospital , Sydney, New South Wales 2010, Australia
| | - Paul M G Curmi
- School of Physics, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Louise J Brown
- Department of Chemistry and Biomolecular Sciences, Macquarie University , Sydney, New South Wales 2109, Australia
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10
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Salao K, Jiang L, Li H, Tsai VWW, Husaini Y, Curmi PMG, Brown LJ, Brown DA, Breit SN. CLIC1 regulates dendritic cell antigen processing and presentation by modulating phagosome acidification and proteolysis. Biol Open 2016; 5:620-30. [PMID: 27113959 PMCID: PMC4874360 DOI: 10.1242/bio.018119] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Intracellular chloride channel protein 1 (CLIC1) participates in inflammatory processes by regulating macrophage phagosomal functions such as pH and proteolysis. Here, we sought to determine if CLIC1 can regulate adaptive immunity by actions on dendritic cells (DCs), the key professional antigen presenting cells. To do this, we first generated bone marrow-derived DCs (BMDCs) from germline CLIC1 gene-deleted (CLIC1−/−) and wild-type (CLIC1+/+) mice, then studied them in vitro and in vivo. We found phagocytosis triggered cytoplasmic CLIC1 translocation to the phagosomal membrane where it regulated phagosomal pH and proteolysis. Phagosomes from CLIC1−/− BMDCs displayed impaired acidification and proteolysis, which could be reproduced if CLIC1+/+, but not CLIC1−/− cells, were treated with IAA94, a CLIC family ion channel blocker. CLIC1−/− BMDC displayed reduced in vitro antigen processing and presentation of full-length myelin oligodendrocyte glycoprotein (MOG) and reduced MOG-induced experimental autoimmune encephalomyelitis. These data suggest that CLIC1 regulates DC phagosomal pH to ensure optimal processing of antigen for presentation to antigen-specific T-cells. Further, they indicate that CLIC1 is a novel therapeutic target to help reduce the adaptive immune response in autoimmune diseases. Summary: DC phagosomes from CLIC1−/− mice display impaired acidification and in vivo and in vitro antigen processing and presentation, revealing CLIC1−/− as a potential therapeutic target in reducing the adaptive immune response in autoimmune diseases.
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Affiliation(s)
- Kanin Salao
- St Vincent's Centre for Applied Medical Research, St. Vincent's Hospital and University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Lele Jiang
- St Vincent's Centre for Applied Medical Research, St. Vincent's Hospital and University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Hui Li
- St Vincent's Centre for Applied Medical Research, St. Vincent's Hospital and University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Vicky W-W Tsai
- St Vincent's Centre for Applied Medical Research, St. Vincent's Hospital and University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Yasmin Husaini
- St Vincent's Centre for Applied Medical Research, St. Vincent's Hospital and University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Paul M G Curmi
- School of Physics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Louise J Brown
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales 2109, Australia
| | - David A Brown
- St Vincent's Centre for Applied Medical Research, St. Vincent's Hospital and University of New South Wales, Sydney, New South Wales 2010, Australia
| | - Samuel N Breit
- St Vincent's Centre for Applied Medical Research, St. Vincent's Hospital and University of New South Wales, Sydney, New South Wales 2010, Australia
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Lallement PA, Brouwer B, Keech O, Hecker A, Rouhier N. The still mysterious roles of cysteine-containing glutathione transferases in plants. Front Pharmacol 2014; 5:192. [PMID: 25191271 PMCID: PMC4138524 DOI: 10.3389/fphar.2014.00192] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 07/26/2014] [Indexed: 12/31/2022] Open
Abstract
Glutathione transferases (GSTs) represent a widespread multigenic enzyme family able to modify a broad range of molecules. These notably include secondary metabolites and exogenous substrates often referred to as xenobiotics, usually for their detoxification, subsequent transport or export. To achieve this, these enzymes can bind non-substrate ligands (ligandin function) and/or catalyze the conjugation of glutathione onto the targeted molecules, the latter activity being exhibited by GSTs having a serine or a tyrosine as catalytic residues. Besides, other GST members possess a catalytic cysteine residue, a substitution that radically changes enzyme properties. Instead of promoting GSH-conjugation reactions, cysteine-containing GSTs (Cys-GSTs) are able to perform deglutathionylation reactions similarly to glutaredoxins but the targets are usually different since glutaredoxin substrates are mostly oxidized proteins and Cys-GST substrates are metabolites. The Cys-GSTs are found in most organisms and form several classes. While Beta and Omega GSTs and chloride intracellular channel proteins (CLICs) are not found in plants, these organisms possess microsomal ProstaGlandin E-Synthase type 2, glutathionyl hydroquinone reductases, Lambda, Iota and Hemerythrin GSTs and dehydroascorbate reductases (DHARs); the four last classes being restricted to the green lineage. In plants, whereas the role of DHARs is clearly associated to the reduction of dehydroascorbate to ascorbate, the physiological roles of other Cys-GSTs remain largely unknown. In this context, a genomic and phylogenetic analysis of Cys-GSTs in photosynthetic organisms provides an updated classification that is discussed in the light of the recent literature about the functional and structural properties of Cys-GSTs. Considering the antioxidant potencies of phenolic compounds and more generally of secondary metabolites, the connection of GSTs with secondary metabolism may be interesting from a pharmacological perspective.
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Affiliation(s)
- Pierre-Alexandre Lallement
- UMR1136, Interactions Arbres - Microorganismes, Université de Lorraine Vandoeuvre-lès-Nancy, France ; UMR1136, Interactions Arbres - Microorganismes, INRA Champenoux, France
| | - Bastiaan Brouwer
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University Umeå, Sweden
| | - Olivier Keech
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University Umeå, Sweden
| | - Arnaud Hecker
- UMR1136, Interactions Arbres - Microorganismes, Université de Lorraine Vandoeuvre-lès-Nancy, France ; UMR1136, Interactions Arbres - Microorganismes, INRA Champenoux, France
| | - Nicolas Rouhier
- UMR1136, Interactions Arbres - Microorganismes, Université de Lorraine Vandoeuvre-lès-Nancy, France ; UMR1136, Interactions Arbres - Microorganismes, INRA Champenoux, France
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Do H, Kim IS, Kim YS, Shin SY, Kim JJ, Mok JE, Park SI, Wi AR, Park H, Kim HW, Yoon HS, Lee JH. Crystallization and preliminary X-ray crystallographic studies of dehydroascorbate reductase (DHAR) from Oryza sativa L. japonica. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2014; 70:781-5. [PMID: 24915093 DOI: 10.1107/s2053230x14009133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 04/22/2014] [Indexed: 11/10/2022]
Abstract
Dehydroascorbate reductase from Oryza sativa L. japonica (OsDHAR), a key enzyme in the regeneration of vitamin C, maintains reduced pools of ascorbic acid to detoxify reactive oxygen species. In previous studies, the overexpression of OsDHAR in transgenic rice increased grain yield and biomass as well as the amount of ascorbate, suggesting that ascorbate levels are directly associated with crop production in rice. Hence, it has been speculated that the increased level of antioxidants generated by OsDHAR protects rice from oxidative damage and increases the yield of rice grains. However, the crystal structure and detailed mechanisms of this important enzyme need to be further elucidated. In this study, recombinant OsDHAR protein was purified and crystallized using the sitting-drop vapour-diffusion method at pH 8.0 and 298 K. Plate-shaped crystals were obtained using 0.15 M potassium bromide, 30%(w/v) PEG MME 2000 as a precipitant, and the crystals diffracted to a resolution of 1.9 Å on beamline 5C at the Pohang Accelerator Laboratory. The X-ray diffraction data indicated that the crystal contained one OsDHAR molecule in the asymmetric unit and belonged to space group P2₁ with unit-cell parameters a=47.03, b=48.38, c=51.83 Å, β=107.41°.
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Affiliation(s)
- Hackwon Do
- Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 406-840, Republic of Korea
| | - Il-Sup Kim
- Department of Biology, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Young-Saeng Kim
- Department of Biology, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Sun-Young Shin
- Department of Biology, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Jin-Ju Kim
- Department of Biology, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Ji-Eun Mok
- Department of Biology, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Seong-Im Park
- Department of Biology, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Ah Ram Wi
- Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 406-840, Republic of Korea
| | - Hyun Park
- Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 406-840, Republic of Korea
| | - Han-Woo Kim
- Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 406-840, Republic of Korea
| | - Ho-Sung Yoon
- Department of Biology, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Jun Hyuck Lee
- Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 406-840, Republic of Korea
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Computational analysis of the soluble form of the intracellular chloride ion channel protein CLIC1. BIOMED RESEARCH INTERNATIONAL 2013; 2013:170586. [PMID: 24089665 PMCID: PMC3780514 DOI: 10.1155/2013/170586] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/26/2013] [Accepted: 06/27/2013] [Indexed: 11/18/2022]
Abstract
The chloride intracellular channel (CLIC) family of proteins has the remarkable property of maintaining both a soluble form and an integral membrane form acting as an ion channel. The soluble form is structurally related to the glutathione-S-transferase family, and CLIC can covalently bind glutathione via an active site cysteine. We report approximately 0.6 μs of molecular dynamics simulations, encompassing the three possible ligand-bound states of CLIC1, using the structure of GSH-bound human CLIC1. Noncovalently bound GSH was rapidly released from the protein, whereas the covalently ligand-bound protein remained close to the starting structure over 0.25 μs of simulation. In the unliganded state, conformational changes in the vicinity of the glutathione-binding site resulted in reduced reactivity of the active site thiol. Elastic network analysis indicated that the changes in the unliganded state are intrinsic to the protein architecture and likely represent functional transitions. Overall, our results are consistent with a model of CLIC function in which covalent binding of glutathione does not occur spontaneously but requires interaction with another protein to stabilise the GSH binding site and/or transfer of the ligand. The results do not indicate how CLIC1 undergoes a radical conformational change to form a transmembrane chloride channel but further elucidate the mechanism by which CLICs are redox controlled.
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14
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Knowles LM, Zewe J, Malik G, Parwani AV, Gingrich JR, Pilch J. CLT1 targets bladder cancer through integrin α5β1 and CLIC3. Mol Cancer Res 2012. [PMID: 23204394 DOI: 10.1158/1541-7786.mcr-12-0300] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
High-grade non-muscle-invasive bladder cancer is commonly treated with Bacillus Calmette-Guérin, an immunotherapeutic that depends on fibronectin and tumor cell integrin α5β1 for internalization into bladder cancer cells. We previously showed that the anti-angiogenic peptide CLT1 forms cytotoxic complexes with fibronectin that are cooperatively internalized into proliferating endothelium through ligation of integrins and chloride intracellular channel 1. While CLT1 has no effect on mature, differentiated cells, we show here that CLT1 is highly cytotoxic for a panel of bladder tumor cell lines as well as a variety of cell lines derived from kidney, lung, breast, and prostate cancer. Paralleling our previous results, we found CLT1-induced tumor cell death to be increased in the presence of fibronectin, which mediated CLT1 internalization and subsequent autophagic cell death in a mechanism that depends on tumor cell integrin α5β1 and chloride intracellular channel 3 (CLIC3). This mechanistic link was further supported by our results showing upregulation of α5β1 and CLIC3 in CLT1-responsive tumor cell lines and colocalization with CLT1 in tumor tissues. Incubating tumor tissue from patients with bladder cancer with fluorescein-conjugated CLT1 resulted in a strong and specific fluorescence whereas normal bladder tissue remained negative. On the basis of its affinity for bladder tumor tissue and strong antitumor effects, we propose that CLT1 could be useful for targeting bladder cancer.
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Affiliation(s)
- Lynn M Knowles
- Department of Urology, University of Pittsburgh School of Medicine, Shadyside Medical Center, Suite G33, 5200 Centre Avenue, Pittsburgh, PA 15232, USA
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15
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Goodchild SC, Curmi PMG, Brown LJ. Structural gymnastics of multifunctional metamorphic proteins. Biophys Rev 2011; 3:143. [PMID: 28510063 DOI: 10.1007/s12551-011-0053-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Accepted: 07/05/2011] [Indexed: 10/17/2022] Open
Abstract
The classic structure-function paradigm holds that a protein exhibits a single well-defined native state that gives rise to its biological function. Nonetheless, over the past few decades, numerous examples of proteins exhibiting biological function arising from multiple structural states of varying disorder have been identified. Most recently, several examples of 'metamorphic proteins', able to interconvert between vastly different native-like topologies under physiological conditions, have been characterised with multiple functions. In this review, we look at the concept of protein metamorphosis in relation to the current understanding of the protein structure-function landscape. Although structural dynamism observed for metamorphic proteins provides a novel source of functional versatility, the dynamic nature of the metamorphic proteins generally makes them difficult to identify and probe using conventional protein structure determination methods. However, as the existence of metamorphic proteins has now been established and techniques enabling the analysis of multiple protein conformers are improving, it is likely that this class will continue to grow in number.
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Affiliation(s)
- Sophia C Goodchild
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia
| | - Paul M G Curmi
- School of Physics, University of New South Wales, Sydney, New South Wales, 2052, Australia.,Centre for Applied Medical Research, St Vincent's Hospital, Sydney, New South Wales, 2010, Australia
| | - Louise J Brown
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, 2109, Australia.
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