Catalytic subunit of the peripheral V1 complex of vacuolar ATPase. V-ATPase vacuolar ATPase is responsible for acidifying a variety of intracellular compartments in eukaryotic cells.
CuratedUniProtKB
According to TCDB this is a transporter from family:
H+- or Na+-translocating F-type, V-type and A-type ATPase (F-ATPase) superfamily 3.A.2.2.4
Interacting selectively and non-covalently with ATP, adenosine 5'-triphosphate, a universally important coenzyme and enzyme regulator.
IEAUniProtKB KW
Hydrogen ion transporting ATP synthase activity, rotational mechanismdefinition[GO:0046933]‹silver
Catalysis of protons from one side of a membrane to the other according to the reaction: ADP + phosphate = ATP + H2O, coupled with transport of H+ down a concentration gradient, by a rotational mechanism.
Catalysis of the transfer of a solute or solutes from one side of a membrane to the other according to the reaction: ATP + H2O + H+(in) = ADP + phosphate + H+(out), by a rotational mechanism.
The directed movement of substances (such as macromolecules, small molecules, ions) into, out of or within a cell, or between cells, or within a multicellular organism by means of some agent such as a transporter or pore.
J. Biol. Chem. 268, 7075-7080 (1993)[PubMed:8463241]
Subunit A is thought to be the main component of the catalytic site of the vacuolar-type H(+)-ATPase. Screening of a cDNA library made from human osteoclastoma tumor tissue revealed the presence of two isoforms of subunit A. HO68 is a cDNA of 3.1 kilobase pairs, corresponding to a mRNA of approximately 3.4 kilobases in osteoclastoma only, encoding a protein of 615 amino acids with a predicted molecular mass of 68177 Da. A second subtype, VA68, corresponding to a mRNA of approximately 4.8 kilobases was present in all tissues analyzed, and codes for a predicted protein of 617 residues and theoretical molecular mass of 68264 Da. These clones share homology with previously published subunit A sequences, and this, together with the tissue distribution of the mRNA, suggests there are ubiquitous (VA68-type) and tissue-specific (HO68-type) isoforms. HO68 shows the closest sequence homology (95% at the amino acid level) to subunit A of a proton-secreting vacuolar-type H(+)-ATPase located in the apical membrane of midgut goblet cells of tobacco hornworm larva (Manduca sexta). We propose that HO68 could correspond to an isoform of subunit A specific for a vacuolar-type H(+)-ATPase located in the osteoclast plasma membrane.
Protein involved in the transport of ions. Such proteins are usually transmembrane and mediate a movement of ions across cell membranes. Transport may be passive (facilitated diffusion; down the electrochemical gradient), or active (against the electrochemical gradient). Active transport requires energy which may come from light, oxidation reactions, ATP hydrolysis, or cotransport of other ions or molecules.
Protein involved in the transport of a molecule (metabolite, protein, etc), a ion or an electron across cell membranes, inside the cell or in a tissue fluid.
Enzyme which catalyzes hydrolysis reaction, i.e. the addition of the hydrogen and hydroxyl ions of water to a molecule with its consequent splitting into two or more simpler molecules.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.