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Alghalayini A, Hossain KR, Moghaddasi S, Turkewitz DR, D’Amario C, Wallach M, Valenzuela SM. In Vitro Enzymatic Studies Reveal pH and Temperature Sensitive Properties of the CLIC Proteins. Biomolecules 2023; 13:1394. [PMID: 37759794 PMCID: PMC10526857 DOI: 10.3390/biom13091394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 09/09/2023] [Accepted: 09/10/2023] [Indexed: 09/29/2023] Open
Abstract
Chloride intracellular ion channel (CLIC) proteins exist as both soluble and integral membrane proteins, with CLIC1 capable of shifting between two distinct structural conformations. New evidence has emerged indicating that members of the CLIC family act as moonlighting proteins, referring to the ability of a single protein to carry out multiple functions. In addition to their ion channel activity, CLIC family members possess oxidoreductase enzymatic activity and share significant structural and sequence homology, along with varying overlaps in their tissue distribution and cellular localization. In this study, the 2-hydroxyethyl disulfide (HEDS) assay system was used to characterize kinetic properties, as well as the temperature and pH profiles of three CLIC protein family members (CLIC1, CLIC3, CLIC4). We also assessed the effects of the drugs rapamycin and amphotericin B, on the three CLIC proteins' enzymatic activity in the HEDS assay. Our results demonstrate CLIC1 to be highly heat-sensitive, with optimal enzymatic activity observed at neutral pH7 and at a temperature of 37 °C, while CLIC3 had higher oxidoreductase activity in more acidic pH5 and was found to be relatively heat stable. CLIC4, like CLIC1, was temperature sensitive with optimal enzymatic activity observed at 37 °C; however, it showed optimal activity in more alkaline conditions of pH8. Our current study demonstrates individual differences in the enzymatic activity between the three CLIC proteins, suggesting each CLIC protein is likely regulated in discrete ways, involving changes in the subcellular milieu and microenvironment.
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Affiliation(s)
- Amani Alghalayini
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia; (A.A.); (K.R.H.); (S.M.); (D.R.T.); (C.D.); (M.W.)
- ARC Research Hub for Integrated Device for End-User Analysis at Low-Levels (IDEAL), Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Khondker Rufaka Hossain
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia; (A.A.); (K.R.H.); (S.M.); (D.R.T.); (C.D.); (M.W.)
- ARC Research Hub for Integrated Device for End-User Analysis at Low-Levels (IDEAL), Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Saba Moghaddasi
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia; (A.A.); (K.R.H.); (S.M.); (D.R.T.); (C.D.); (M.W.)
| | - Daniel R. Turkewitz
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia; (A.A.); (K.R.H.); (S.M.); (D.R.T.); (C.D.); (M.W.)
| | - Claudia D’Amario
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia; (A.A.); (K.R.H.); (S.M.); (D.R.T.); (C.D.); (M.W.)
| | - Michael Wallach
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia; (A.A.); (K.R.H.); (S.M.); (D.R.T.); (C.D.); (M.W.)
| | - Stella M. Valenzuela
- School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia; (A.A.); (K.R.H.); (S.M.); (D.R.T.); (C.D.); (M.W.)
- ARC Research Hub for Integrated Device for End-User Analysis at Low-Levels (IDEAL), Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, Australia
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Hossain KR, Escobar Bermeo JD, Warton K, Valenzuela SM. New Approaches and Biomarker Candidates for the Early Detection of Ovarian Cancer. Front Bioeng Biotechnol 2022; 10:819183. [PMID: 35223789 PMCID: PMC8867026 DOI: 10.3389/fbioe.2022.819183] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- K R Hossain
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - J D Escobar Bermeo
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.,ARC Research Hub for Integrated Device for End-user Analysis at Low-levels (IDEAL), Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
| | - K Warton
- School of Women's and Children's Health, Faculty of Medicine and Health, University of New South Wales, South Wales, NSW, Australia
| | - S M Valenzuela
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia.,ARC Research Hub for Integrated Device for End-user Analysis at Low-levels (IDEAL), Faculty of Science, University of Technology Sydney, Sydney, NSW, Australia
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Turkewitz DR, Moghaddasi S, Alghalayini A, D'Amario C, Ali HM, Wallach M, Valenzuela SM. Comparative study of His- and Non-His-tagged CLIC proteins, reveals changes in their enzymatic activity. Biochem Biophys Rep 2021; 26:101015. [PMID: 34036185 PMCID: PMC8138732 DOI: 10.1016/j.bbrep.2021.101015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/15/2021] [Accepted: 05/02/2021] [Indexed: 10/29/2022] Open
Abstract
The chloride intracellular ion channel protein (CLIC) family are a unique set of ion channels that can exist as soluble and integral membrane proteins. New evidence has emerged that demonstrates CLICs' possess oxidoreductase enzymatic activity and may function as either membrane-spanning ion channels or as globular enzymes. To further characterize the enzymatic profile of members of the CLIC family and to expand our understanding of their functions, we expressed and purified recombinant CLIC1, CLIC3, and a non-functional CLIC1-Cys24A mutant using a Histidine tag, bacterial protein expression system. We demonstrate that the presence of the six-polyhistidine tag at the amino terminus of the proteins led to a decrease in their oxidoreductase enzymatic activity compared to their non-His-tagged counterparts, when assessed using 2-hydroxyethyl disulfide as a substrate. These results strongly suggest the six-polyhistidine tag alters CLIC's structure at the N-terminus, which also contains the enzyme active site. It also raises the need for caution in use of His-tagged proteins when assessing oxidoreductase protein enzymatic function.
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Affiliation(s)
- Daniel R Turkewitz
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Saba Moghaddasi
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Amani Alghalayini
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia.,ARC Research Hub for Integrated Device for End-user Analysis at Low-levels (IDEAL), Faculty of Science, University of Technology Sydney, NSW, 2007, Australia
| | - Claudia D'Amario
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Hala M Ali
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Michael Wallach
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Stella M Valenzuela
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia.,ARC Research Hub for Integrated Device for End-user Analysis at Low-levels (IDEAL), Faculty of Science, University of Technology Sydney, NSW, 2007, Australia
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Abstract
Cl- intracellular channels (CLICs) are a family of six evolutionary conserved cytosolic proteins that exist in both soluble and membrane-associated forms; however, their functions have long been elusive. Soluble CLICs adopt a glutathione S-transferase (GST)-fold, can induce ion currents in artificial membranes and show oxidoreductase activity in vitro, but there is no convincing evidence of CLICs having such activities in vivo. Recent studies have revealed a role for CLIC proteins in Rho-regulated cortical actin dynamics as well as vesicular trafficking and integrin recycling, the latter of which are under the control of Rab GTPases. In this Commentary, we discuss the emerging roles of CLIC proteins in these processes and the lessons learned from gene-targeting studies. We also highlight outstanding questions regarding the molecular function(s) of these important but still poorly understood proteins.
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Affiliation(s)
- Elisabetta Argenzio
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam 1066CX, The Netherlands
| | - Wouter H Moolenaar
- Division of Cell Biology, The Netherlands Cancer Institute, Amsterdam 1066CX, The Netherlands
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