Regulation of V-ATPases by reversible disassembly

V-ATPases consist of a complex of peripheral subunits containing catalytic sites for ATP hydrolysis, the V-1 sector, attached to several membrane subunits containing a proton pore, the V-0 sector. ATP-driven proton transport requires structural and functional coupling of the two sectors, but in vivo, the interaction between the V-1 and V-0 sectors is dynamic and is regulated by extracellular conditions. Dynamic instability appears to be a general characteristic of V-ATPases and, in yeast cells, the assembly state of V-ATPases is governed by glucose availability. The structural and functional implications of reversible disassembly of V-ATPases are discussed. (C) 2000 Federation of European Biochemical Societies.