Structural gene organization and evolutionary aspects of the V-ATPase accessory subunit Ac45

• Published in: Biochimica et biophysica acta 2002-04, Vol.1574 (3), p.245-254
• Main Authors: Schoonderwoert, Vincent Th.G., Martens, Gerard J.M.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Chromosome X; Cloning, Molecular; Gene promoter region; Membrane Proteins - chemistry; Membrane Proteins - genetics; Mice; Molecular Sequence Data; Mouse; Promoter Regions, Genetic; Proton pump; Sequence Alignment; Vacuolar acidification; Vacuolar Proton-Translocating ATPases - chemistry; Vacuolar Proton-Translocating ATPases - genetics; X Chromosome; Xq28
• ISSN: 0167-4781; 0006-3002; 1879-2634
• DOI: 10.1016/S0167-4781(01)00368-2

The vacuolar H +-ATPase (V-ATPase) is a multisubunit enzyme that couples ATP hydrolysis to proton pumping across membranes. The intracellular targeting and activity of the V-ATPase may be regulated via proteins that interact with the pump such as the accessory subunit Ac45. Here we report the isolation and characterization of the gene encoding Ac45. This single-copy gene is located in a gene-dense region of chromosome Xq and consists of 10 exons spanning ∼8 kb in the mouse and human genomes. The gene structure is poorly conserved in that its invertebrate orthologs of Caenorhabditis elegans and Drosophila melanogaster encompass only six and four exons extending over 4.1 and 2.1 kb, respectively. Furthermore, the overall degree of amino acid sequence identity between the mammalian and invertebrate Ac45 proteins is very low (