Chloride Intracellular Channel Protein 5 (CLIC5)

Chloride intracellular channels are involved in chloride ion transport within various subcellular compartments. CLIC5 specifically associates with the cytoskeleton of placenta microvilli. CLIC5 can form ion channel in bilayers and is regulated by actin. Northern blot analysis revealed high expression of a major 6.4-kb transcript, as well as minor 3.8- and 2.3-kb transcripts, in heart and skeletal muscle, with moderate levels in kidney, lung, and placenta. Immunoblot analysis showed strong binding of CLIC5 to ezrin residues 475 to 586, whereas binding of CLIC4 was low and binding of CLIC1 was undetectable. Expression of CLIC5 was enriched in microvillus extracts compared with whole placenta tissue. Immunofluorescence microscopy demonstrated highest expression on the apical surface of trophoblast epithelium.