| First Author | van Hille B | Year | 1993 |
| Journal | J Biol Chem | Volume | 268 |
| Issue | 10 | Pages | 7075-80 |
| PubMed ID | 8463241 | Mgi Jnum | J:49139 |
| Mgi Id | MGI:1276764 | Doi | 10.1016/s0021-9258(18)53147-1 |
| Citation | van Hille B, et al. (1993) Identification of two subunit A isoforms of the vacuolar H(+)-ATPase in human osteoclastoma. J Biol Chem 268(10):7075-80 |
| abstractText | 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. |
