El Khoury Wendy, Hossain Khondker Rufaka, Alghalayini Amani, Ali Hala M, Valenzuela Stella M
School of Life Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia.
Biomolecules. 2025 Aug 22;15(9):1213. doi: 10.3390/biom15091213.
Increasing evidence points to members of the chloride intracellular ion channel (CLIC) protein family performing a variety of functions within cells-classifying them as moonlighting proteins-and serving as natural cellular antioxidant protective agents. Apart from their role as membrane-inserting ion channels, members of the CLIC family also possess enzymatic oxidoreduction activity in their soluble form. The current study is the first to specifically examine the S-glutathionylation catalytic activity of several purified recombinant CLIC protein members (rCLIC1, rCLIC3, and rCLIC4) by directly measuring their ability to deglutathionylate and glutathionylate a synthetic model peptide via an in vitro tryptophan fluorescence quenching assay. Effects of pH and temperature on this activity were also assessed. Our findings provide insights into a likely previously uncharacterised mechanism by which CLIC proteins serve as cellular antioxidant protective enzymes via their S-glutathionylation capabilities.
越来越多的证据表明，氯离子细胞内离子通道（CLIC）蛋白家族成员在细胞内发挥多种功能——将它们归类为兼职蛋白——并作为天然的细胞抗氧化保护剂。除了作为插入膜的离子通道的作用外，CLIC家族成员在其可溶形式下还具有酶促氧化还原活性。本研究首次通过体外色氨酸荧光猝灭测定法直接测量几种纯化的重组CLIC蛋白成员（rCLIC1、rCLIC3和rCLIC4）使合成模型肽脱谷胱甘肽化和谷胱甘肽化的能力，专门研究了它们的S-谷胱甘肽化催化活性。还评估了pH和温度对该活性的影响。我们的研究结果为CLIC蛋白通过其S-谷胱甘肽化能力作为细胞抗氧化保护酶的一种可能以前未被表征的机制提供了见解。
