| Structural highlights
Function
CLIC1_HUMAN Can insert into membranes and form chloride ion channels. Channel activity depends on the pH. Membrane insertion seems to be redox-regulated and may occur only under oxydizing conditions. Involved in regulation of the cell cycle.[1] [2] [3] [4] [5] [6] [7]
Publication Abstract from PubMed
Ascorbate is an important cellular antioxidant that gets readily oxidized to dehydroascorbate (DHA). Recycling of DHA is therefore paramount in the maintenance of cellular homeostasis and preventing oxidative stress. Dehydroascorbate reductases (DHARs), in conjunction with glutathione (GSH), carry out this vital process in eukaryotes, among which plant DHARs have garnered considerable attention. A detailed kinetic analysis of plant DHARs relative to their human counterparts is, however, lacking. Chloride intracellular channels (HsCLICs) are close homologs of plant DHARs, recently demonstrated to share their enzymatic activity. This study reports the highest turnover rate for a plant DHAR from stress adapted Pennisetum glaucum (PgDHAR). In comparison, HsCLICs 1, 3, and 4 reduced DHA at a significantly lower rate. We further show that the catalytic cysteine from both homologs was susceptible to varying degrees of oxidation, validated by crystal structures and mass-spectrometry. Our findings may have broader implications on crop improvement using pearl millet DHAR vis-a-vis discovery of cancer therapeutics targeting Vitamin-C recycling capability of human CLICs.
Comparative kinetic analysis of ascorbate (Vitamin-C) recycling dehydroascorbate reductases from plants and humans.,Das BK, Kumar A, Sreekumar SN, Ponraj K, Gadave K, Kumar S, Murali Achary VM, Ray P, Reddy MK, Arockiasamy A Biochem Biophys Res Commun. 2021 Dec 29;591:110-117. doi:, 10.1016/j.bbrc.2021.12.103. PMID:35007834[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Valenzuela SM, Martin DK, Por SB, Robbins JM, Warton K, Bootcov MR, Schofield PR, Campbell TJ, Breit SN. Molecular cloning and expression of a chloride ion channel of cell nuclei. J Biol Chem. 1997 May 9;272(19):12575-82. PMID:9139710
- ↑ Tonini R, Ferroni A, Valenzuela SM, Warton K, Campbell TJ, Breit SN, Mazzanti M. Functional characterization of the NCC27 nuclear protein in stable transfected CHO-K1 cells. FASEB J. 2000 Jun;14(9):1171-8. PMID:10834939
- ↑ Valenzuela SM, Mazzanti M, Tonini R, Qiu MR, Warton K, Musgrove EA, Campbell TJ, Breit SN. The nuclear chloride ion channel NCC27 is involved in regulation of the cell cycle. J Physiol. 2000 Dec 15;529 Pt 3:541-52. PMID:11195932
- ↑ Tulk BM, Kapadia S, Edwards JC. CLIC1 inserts from the aqueous phase into phospholipid membranes, where it functions as an anion channel. Am J Physiol Cell Physiol. 2002 May;282(5):C1103-12. PMID:11940526 doi:10.1152/ajpcell.00402.2001
- ↑ Warton K, Tonini R, Fairlie WD, Matthews JM, Valenzuela SM, Qiu MR, Wu WM, Pankhurst S, Bauskin AR, Harrop SJ, Campbell TJ, Curmi PM, Breit SN, Mazzanti M. Recombinant CLIC1 (NCC27) assembles in lipid bilayers via a pH-dependent two-state process to form chloride ion channels with identical characteristics to those observed in Chinese hamster ovary cells expressing CLIC1. J Biol Chem. 2002 Jul 19;277(29):26003-11. Epub 2002 Apr 26. PMID:11978800 doi:https://dx.doi.org/10.1074/jbc.M203666200
- ↑ Harrop SJ, DeMaere MZ, Fairlie WD, Reztsova T, Valenzuela SM, Mazzanti M, Tonini R, Qiu MR, Jankova L, Warton K, Bauskin AR, Wu WM, Pankhurst S, Campbell TJ, Breit SN, Curmi PM. Crystal structure of a soluble form of the intracellular chloride ion channel CLIC1 (NCC27) at 1.4-A resolution. J Biol Chem. 2001 Nov 30;276(48):44993-5000. Epub 2001 Sep 10. PMID:11551966 doi:10.1074/jbc.M107804200
- ↑ Littler DR, Harrop SJ, Fairlie WD, Brown LJ, Pankhurst GJ, Pankhurst S, DeMaere MZ, Campbell TJ, Bauskin AR, Tonini R, Mazzanti M, Breit SN, Curmi PM. The intracellular chloride ion channel protein CLIC1 undergoes a redox-controlled structural transition. J Biol Chem. 2004 Mar 5;279(10):9298-305. Epub 2003 Nov 12. PMID:14613939 doi:https://dx.doi.org/10.1074/jbc.M308444200
- ↑ Das BK, Kumar A, Sreekumar SN, Ponraj K, Gadave K, Kumar S, Murali Achary VM, Ray P, Reddy MK, Arockiasamy A. Comparative kinetic analysis of ascorbate (Vitamin-C) recycling dehydroascorbate reductases from plants and humans. Biochem Biophys Res Commun. 2022 Feb 5;591:110-117. PMID:35007834 doi:10.1016/j.bbrc.2021.12.103
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