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Chloride ATPase pumps in nature: do they exist?
Author(s) -
GERENCSER GEORGE A.,
ZHANG JIANLIANG
Publication year - 2003
Publication title -
biological reviews
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.993
H-Index - 165
eISSN - 1469-185X
pISSN - 1464-7931
DOI - 10.1017/s146479310200605x
Subject(s) - antiporter , chloride , electrochemical gradient , chemistry , active transport , atpase , ion transporter , biophysics , mediated transport , membrane , membrane transport , chloride channel , membrane potential , ion pump , electrochemical potential , electrochemistry , biochemistry , ion , biology , enzyme , organic chemistry , electrode
Five widely documented mechanisms for chloride transport across biological membranes are known: anioncoupled antiport, Na + and H + ‐coupled symport, Cl − channels and an electrochemical coupling process. These transport processes for chloride are either secondarily active or are driven by the electrochemical gradient for chloride. Until recently, the evidence in favour of a primary active transport mechanism for chloride has been inconclusive despite numerous reports of cellular Cl − ‐stimulated ATPases coexisting, in the same tissue, with uphill ATP‐dependent chloride transport. Cl − ‐stimulated ATPase activity is a ubiquitous property of practically all cells with the major location being of mitochondrial origin. It also appears that plasma membranes are sites of Cl − ‐stimulated ATPase pump activity. Recent studies of Cl − ‐stimulated ATPase activity and ATP‐dependent chloride transport in the same plasma membrane system, including liposomes, strongly suggest a mediation by the ATPase in the net movement of chloride up its electrochemical gradient across the plasma membrane structure. Contemporary evidence points to the existence of Cl − ‐ATPase pumps; however, these primary active transporters exist as either P‐, F‐ or V‐type ATPase pumps depending upon the tissue under study.