Identification of two subunit A isoforms of the vacuolar H(+)-ATPase in human osteoclastoma.

Article Details

Citation

van Hille B, Richener H, Evans DB, Green JR, Bilbe G

Identification of two subunit A isoforms of the vacuolar H(+)-ATPase in human osteoclastoma.

J Biol Chem. 1993 Apr 5;268(10):7075-80.

PubMed ID
8463241 [ View in PubMed
]
Abstract

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.

DrugBank Data that Cites this Article

Polypeptides
NameUniProt ID
V-type proton ATPase catalytic subunit AP38606Details