Structure, function and regulation of the vacuolar (H+)-ATPase.
The vacuolar (H+)-ATPases (or V-ATPases) function in the acidification of intracellular compartments in eukaryotic cells. The V-ATPases are multisubunit complexes composed of two functional domains. The peripheral V1 domain, a 500-kDa complex responsible for ATP hydrolysis, contains at least eight different subunits of molecular weight 70-13 (subunits A-H). The integral V0 domain, a 250-kDa complex, functions in proton translocation and contains at least five different subunits of molecular weight 100-17 (subunits a-d). Biochemical and genetic analysis has been used to identify subunits and residues involved in nucleotide binding and hydrolysis, proton translocation, and coupling of these activities. Several mechanisms have been implicated in the regulation of vacuolar acidification in vivo, including control of pump density, regulation of assembly of V1 and V0 domains, disulfide bond formation, activator or inhibitor proteins, and regulation of counterion conductance. Recent information concerning targeting and regulation of V-ATPases has also been obtained.
Stevens
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Institute of Molecular Biology, University of Oregon, Eugene 97403-1229, USA. stevens@molbio.uoregon.edu
Forgac
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D000818:Animals; D001665:Binding Sites; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D017494:Proton Pumps; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases
D017494:Proton Pumps; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases