Regulation of proton-translocating V-ATPases

Vacuolar-type ATPases (V-ATPases) are proton-translocating enzymes that occur in the endomembranes of all eukaryotes and in the plasma membranes of many eukaryotes. They are multisubunit, heteromeric proteins composed of two structural domains, a peripheral, catalytic V₁ domain and a membrane-spanning V_o domain. Both the multitude of locations and the heteromultimeric structure make it likely that the expression and the activity of V-ATPases are regulated in various ways. Regulation of gene expression encompasses control of transcription as well as control at the post-transcriptional level. Regulation of enzyme activity encompasses many diverse mechanisms such as disassembly/reassembly of V₁ and V_o domains, oxidation of SH groups, control by activator and inhibitor proteins or by small signalling molecules, and sorting of the holoenzyme or its subunits to target membranes.