Cl(-)-ATPases: Novel primary active transporters in biology.
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 medication 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. J. Exp. Zool. 289:215-223, 2001.
Gerencser
G A
GA
Department of Physiology, College of Medicine, University of Florida, Gainesville, Florida 32610, USA. gag@phys.med.ufl.edu
Zhang
J
J
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D027321:Anion Transport Proteins; D001693:Biological Transport, Active; D002462:Cell Membrane / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D008954:Models, Biological
D027321:Anion Transport Proteins; D002712:Chlorides; D000251:Adenosine Triphosphatases; C031652:anion-sensitive ATPases