Premium
Functional reconstitution of mammalian ‘chloride intracellular channels’ CLIC1, CLIC4 and CLIC5 reveals differential regulation by cytoskeletal actin
Author(s) -
Singh H.,
Cousin M. A.,
Ashley R. H.
Publication year - 2007
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2007.06145.x
Subject(s) - cytoskeleton , microbiology and biotechnology , intracellular , actin , cytosol , actin cytoskeleton , cytochalasin d , chloride channel , transmembrane channels , biology , organelle , cytochalasin b , chemistry , ion channel , biophysics , cell , biochemistry , receptor , voltage gated ion channel , enzyme
Chloride intracellular channels (CLICs) are soluble, signal peptide‐less proteins that are distantly related to Ω‐type glutathione‐ S ‐transferases. Although some CLICs bypass the classical secretory pathway and autoinsert into cell membranes to form ion channels, their cellular roles remain unclear. Many CLICs are strongly associated with cytoskeletal proteins, but the role of these associations is not known. In this study, we incorporated purified, recombinant mammalian CLIC1, CLIC4 and (for the first time) CLIC5 into planar lipid bilayers, and tested the hypothesis that the channels are regulated by actin. CLIC5 formed multiconductance channels that were almost equally permeable to Na + , K + and Cl – , suggesting that the ‘CLIC’ nomenclature may need to be revised. CLIC1 and CLIC5, but not CLIC4, were strongly and reversibly inhibited (or inactivated) by ‘cytosolic’ F‐actin in the absence of any other protein. This inhibition effect on channels could be reversed by using cytochalasin to disrupt the F‐actin. We suggest that actin‐regulated membrane CLICs could modify solute transport at key stages during cellular events such as apoptosis, cell and organelle division and fusion, cell‐volume regulation, and cell movement.