An electrogenic chloride pump in a zoological membrane

Two widely documented mechanisms of chloride transport across animal plasma membranes are anion‐coupled antiport and sodium‐coupled symport. No direct genetic evidence has yet been provided for primary active chloride transport despite numerous reports of cellular Cl−‐stimulated ATPases coexisting, in the same tissue, with uphill chloride transport that could not be accounted for by the two common chloride transport processes. Cl−‐stimulated ATPases are a common property of practically all animal cells, with the major location being of mitochondrial origin. It also appears that the plasma membranes of animal cells are sites of Cl−‐stimulated ATPase activity. Recent studies of Cl−‐stimulated ATPase activity and chloride transport in the same membrane system, including liposomes, suggest a mediation by the ATPase in net movement of chloride up its electrochemical gradient across animal plasma membranes. Further studies, especially from a molecular biological perspective, are required to confirm a direct transport role to plasma membrane‐localized Cl−‐stimulated ATPases. © 1996 Wiley‐Liss, Inc.