title: Oxidation promotes insertion of the CLIC1 chloride intracellular channel into the membrane.
abstract: Members of the chloride intracellular channel (CLIC) family exist primarily as soluble proteins but can also auto-insert into cellular membranes to form ion channels. While little is known about the process of CLIC membrane insertion, a unique feature of mammalian CLIC1 is its ability to undergo a dramatic structural metamorphosis between a monomeric glutathione-S-transferase homolog and an all-helical dimer upon oxidation in solution. Whether this oxidation-induced metamorphosis facilitates CLIC1 membrane insertion is unclear. In this work, we have sought to characterise the role of oxidation in the process of CLIC1 membrane insertion. We examined how redox conditions modify the ability of CLIC1 to associate with and insert into the membrane using fluorescence quenching studies and a sucrose-loaded vesicle sedimentation assay to measure membrane binding. Our results suggest that oxidation of monomeric CLIC1, in the presence of membranes, promotes insertion into the bilayer more effectively than the oxidised CLIC1 dimer.
authors.affiliation: Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, NSW, 2109, Australia.
authors.forename: Sophia C
authors.initials: SC
authors.lastname: Goodchild
authors.forename: Michael W
authors.initials: MW
authors.lastname: Howell
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Cordina
authors.forename: Dene R
authors.initials: DR
authors.lastname: Littler
authors.forename: Samuel N
authors.initials: SN
authors.lastname: Breit
authors.forename: Paul M G
authors.initials: PM
authors.lastname: Curmi
authors.forename: Louise Jennifer
authors.initials: LJ
authors.lastname: Brown
mesh_terms: D020106:Acrylamide / Q000494:pharmacology; D002462:Cell Membrane / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D018118:Chloride Channels / Q000737:chemistry* / Q000378:metabolism*; D054879:Halogenation; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010743:Phospholipids / Q000737:chemistry / Q000494:pharmacology; D016062:Porosity; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D012995:Solubility; D013050:Spectrometry, Fluorescence; D013395:Sucrose / Q000378:metabolism
chemical_list: D018118:Chloride Channels; D008051:Lipid Bilayers; D010743:Phospholipids; D020106:Acrylamide; D013395:Sucrose