The role of individual domains and the significance of shedding of ATP6AP2/(pro)renin receptor in vacuolar H(+)-ATPase biogenesis

• Published in: PloS one 2013-11, Vol.8 (11), p.e78603-e78603
• Main Authors: Kinouchi, Kenichiro, Ichihara, Atsuhiro, Sano, Motoaki, Sun-Wada, Ge-Hong, Wada, Yoh, Ochi, Hiroki, Fukuda, Toru, Bokuda, Kanako, Kurosawa, Hideaki, Yoshida, Naohiro, Takeda, Shu, Fukuda, Keiichi, Itoh, Hiroshi
• Format: Article
• Language: English
• Subjects: Acidification; Adenosine triphosphatase; Adenoviridae - genetics; Adenoviridae - metabolism; Amino acids; Animals; Autophagy - genetics; Basal ganglia; Biosynthesis; Cardiology; Central nervous system diseases; Cleavage; Deletion mutant; Embryo, Mammalian; Endocrinology; Endoplasmic reticulum; Fibroblasts - cytology; Fibroblasts - metabolism; Furin; Furin - metabolism; Gene Expression; Genetic Vectors; Golgi apparatus; H+-transporting ATPase; Humans; Hydrogen; Hypertension; Internal medicine; Kinases; Medicine; Metabolism; Mice; Movement disorders; Mutation; Nephrology; Primary Cell Culture; Protein Isoforms - chemistry; Protein Isoforms - genetics; Protein Isoforms - metabolism; Protein Structure, Tertiary; Proteins; Proton-Translocating ATPases - antagonists & inhibitors; Proton-Translocating ATPases - chemistry; Proton-Translocating ATPases - genetics; Proton-Translocating ATPases - metabolism; Receptors, Cell Surface - antagonists & inhibitors; Receptors, Cell Surface - chemistry; Receptors, Cell Surface - genetics; Receptors, Cell Surface - metabolism; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Renin; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; Saccharomyces cerevisiae; Shedding; Spasticity; trans-Golgi Network - metabolism; Transfection; Vacuolar Proton-Translocating ATPases - antagonists & inhibitors; Vacuolar Proton-Translocating ATPases - chemistry; Vacuolar Proton-Translocating ATPases - genetics; Vacuolar Proton-Translocating ATPases - metabolism
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0078603

The ATPase 6 accessory protein 2 (ATP6AP2)/(pro)renin receptor (PRR) is essential for the biogenesis of active vacuolar H(+)-ATPase (V-ATPase). Genetic deletion of ATP6AP2/PRR causes V-ATPase dysfunction and compromises vesicular acidification. Here, we characterized the domains of ATP6AP2/PRR involved in active V-ATPase biogenesis. Three forms of ATP6AP2/PRR were found intracellularly: full-length protein and the N- and C-terminal fragments of furin cleavage products, with the N-terminal fragment secreted extracellularly. Genetic deletion of ATP6AP2/PRR did not affect the protein stability of V-ATPase subunits. The extracellular domain (ECD) and transmembrane domain (TM) of ATP6AP2/PRR were indispensable for the biogenesis of active V-ATPase. A deletion mutant of ATP6AP2/PRR, which lacks exon 4-encoded amino acids inside the ECD (Δ4M) and causes X-linked mental retardation Hedera type (MRXSH) and X-linked parkinsonism with spasticity (XPDS) in humans, was defective as a V-ATPase-associated protein. Prorenin had no effect on the biogenesis of active V-ATPase. The cleavage of ATP6AP2/PRR by furin seemed also dispensable for the biogenesis of active V-ATPase. We conclude that the N-terminal ECD of ATP6AP2/PRR, which is also involved in binding to prorenin or renin, is required for the biogenesis of active V-ATPase. The V-ATPase assembly occurs prior to its delivery to the trans-Golgi network and hence shedding of ATP6AP2/PRR would not affect the biogenesis of active V-ATPase.