Structural and functional features of yeast V-ATPase subunit C.
V-ATPase is a multi-subunit membrane protein complex, it translocates protons across biological membranes, generating electrical and pH gradients which are used for varieties of cellular processes. V-ATPase is composed of two distinct sub-complexes: a membrane bound V0 sub-complex, composed of 6 different subunits, which is responsible for proton transport and a soluble cytosolic facing V1 sub-complex, composed of 8 different subunits which hydrolyse ATP. The two sub-complexes are held together via a flexible stator. One of the main features of eukaryotic V-ATPase is its ability to reversibly dissociate to its sub-complexes in response to changing cellular conditions, which arrest both proton translocation and ATP hydrolysis, suggesting a regulation function. Subunit C (vma5p in yeast) was shown by several biochemical, genetic and recent structural data to function as a flexible stator holding the two sectors of the complex together and regulating the reversible association/dissociation of the complex, partly via association with F-actin filaments. Structural features of subunit C that allow smooth energy conversion and interaction with actin and nucleotides are discussed.
Drory
Omri
O
Department of Biochemistry, The George S. Wise Faculty of Life Sciences, The Daniella Rich Institute for Structural Biology, Tel Aviv University, Tel Aviv 69978, Israel.
Nelson
Nathan
N
D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D001692:Biological Transport; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D011522:Protons; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry* / Q000378:metabolism; D015003:Yeasts / Q000201:enzymology
D000199:Actins; D021122:Protein Subunits; D011522:Protons; D000255:Adenosine Triphosphate; D025262:Vacuolar Proton-Translocating ATPases