RT Journal Article SR Electronic T1 Zn2+ triggered two-step mechanism of CLIC1 membrane insertion and activation into chloride channels JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.10.25.465729 DO 10.1101/2021.10.25.465729 A1 Lorena Varela A1 Alex C. Hendry A1 Joseph Cassar A1 Ruben Martin-Escolano A1 Diego Cantoni A1 John C Edwards A1 Vahitha Abdul-Salam A1 Jose L. Ortega-Roldan YR 2021 UL http://biorxiv.org/content/early/2021/10/26/2021.10.25.465729.abstract AB The CLIC protein family displays the unique feature of altering its structure from a soluble form to a membrane-bound chloride channel. CLIC1, a member of this family, is found in the cytoplasm or in internal and the plasma membranes, with membrane relocalisation linked to endothelial disfunction, tumour proliferation and metastasis. The molecular switch promoting CLIC1 activation remains unclear. Here, cellular chloride efflux assays and immunofluorescence microscopy studies have identified Zn2+ intracellular release as the trigger for CLIC1 activation and membrane relocalisation. Biophysical assays confirmed specific binding to Zn2+, inducing membrane association and enhancing chloride efflux in a pH dependent manner. Together, our results identify a two-step mechanism with Zn2+ binding as the molecular switch promoting CLIC1 membrane insertion, followed by pH activation of chloride efflux.Competing Interest StatementThe authors have declared no competing interest.