Structural organization of the V-ATPase and its implications for regulatory assembly and disassembly.
V-ATPases (vacuolar ATPases) are membrane-bound multiprotein complexes that are localized in the endomembrane systems of eukaryotic cells and in the plasma membranes of some specialized cells. They couple ATP hydrolysis with the transport of protons across membranes. On nutrient shortage, V-ATPases disassemble into a membrane-embedded part (V0), which contains the proton translocation machinery, and an extrinsic part (V1), which carries the nucleotide-binding sites. Disassembly decouples ATP hydrolysis and proton translocation. Furthermore, the disassembled parts are inactive, leading to an efficient shutdown of ATP consumption. On restoring the nutrient levels, V1 and V0 reassemble and restore ATP-hydrolysis activity coupled with proton translocation. This reversible assembly/disassembly process has certain conformational constraints, which are best fulfilled by adopting a unique conformation before disassembly.
Diepholz
Meikel
M
Structural and Computational Biology Unit, EMBL (European Molecular Biology Laboratory), Meyerhofstrasse 1, 69117 Heidelberg, Germany.
Börsch
Michael
M
Böttcher
Bettina
B
D008958:Models, Molecular; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000737:chemistry / Q000378:metabolism; D015003:Yeasts / Q000166:cytology / Q000378:metabolism
D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D025262:Vacuolar Proton-Translocating ATPases