Cl(-)-ATPases: biological active transporters.
Five widely documented mechanisms of chloride transport across plasma membranes are: anion-coupled antiport; sodium and hydrogen-coupled symport; Cl- channels; and an electrochemical coupling process. No genetic evidence has yet been provided for primary active chloride transport despite numerous reports of cellular Cl(-)-stimulated ATPases co-existing, in the same tissue, with uphill chloride transport that could not be accounted for by the five common chloride transport processes. Cl(-)-stimulated ATPase activity is a common property of practically all biological cells with the major location being of mitochondrial origin. It also appears that plasma membranes are sites of Cl(-)-stimulated ATPase activity. Recent studies of Cl(-)-stimulated ATPase activity and active 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 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.
Gerencser
G A
GA
Department of Physiology and Department of Medicine, College of Medicine, University of Florida, Gainesville 32610-0274, USA.
Zhang
J
J
D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001048:Aplysia; D002712:Chlorides / Q000378:metabolism*; D007700:Kinetics; D008970:Molecular Weight
D002712:Chlorides; D000251:Adenosine Triphosphatases