Biosynthesis and regulation of the yeast vacuolar H+-ATPase.
The yeast V-ATPase is highly similar to V-ATPases of higher organisms and has proved to be a biochemically and genetically accessible model for many aspects of V-ATPase function. Like other V-ATPases, the yeast enzyme consists of a complex of peripheral membrane proteins, the V1 sector, attached to a complex of integral membrane subunits, the V0 sector. Multiple pathways for biosynthetic assembly of the enzyme appear to be available to cells containing a full complement of subunits and enzyme activity may be further controlled during biosynthesis by a protease activity localized to the late Golgi apparatus. Surprisingly, the assembled V-ATPase is not a static structure. Instead, fully assembled V1V0 complexes appear to exist in a dynamic equilibrium with inactive cytosolic V1 and membrane-bound V0 complexes and this equilibrium can be rapidly shifted in response to changes in carbon source. The reversible disassembly of the yeast V-ATPase may be a novel regulatory mechanism, common to V-ATPases, that works in vivo in coordination with many other regulatory mechanisms.
Kane
P M
PM
Department of Biochemistry and Molecular Biology, SUNY Health Science Center, Syracuse, New York 13210, USA.
D010084:Oxidation-Reduction; D043484:Proprotein Convertases; D011487:Protein Conformation; D017494:Proton Pumps / Q000096:biosynthesis* / Q000502:physiology; D006180:Proton-Translocating ATPases / Q000096:biosynthesis* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D013381:Subtilisins / Q000378:metabolism; D025262:Vacuolar Proton-Translocating ATPases; D015003:Yeasts / Q000201:enzymology*
D017494:Proton Pumps; D029701:Saccharomyces cerevisiae Proteins; D043484:Proprotein Convertases; D013381:Subtilisins; C058751:KEX2 protein, S cerevisiae; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases