The role of individual domains and the significance of shedding of ATP6AP2/(pro)renin receptor in vacuolar H(+)-ATPase biogenesis.
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.
Division of Endocrinology, Metabolism, and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo, Japan.
Kenichiro
K
Kinouchi
Atsuhiro
A
Ichihara
Motoaki
M
Sano
Ge-Hong
GH
Sun-Wada
Yoh
Y
Wada
Hiroki
H
Ochi
Toru
T
Fukuda
Kanako
K
Bokuda
Hideaki
H
Kurosawa
Naohiro
N
Yoshida
Shu
S
Takeda
Keiichi
K
Fukuda
Hiroshi
H
Itoh
D000256:Adenoviridae / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001343:Autophagy / Q000235:genetics; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism*; D045683:Furin / Q000378:metabolism; D015870:Gene Expression; D005822:Genetic Vectors; D006801:Humans; D051379:Mice; D009154:Mutation; D061251:Primary Cell Culture; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D025262:Vacuolar Proton-Translocating ATPases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D021601:trans-Golgi Network / Q000378:metabolism*; D000093342:Prorenin Receptor
D045683:Furin; D020033:Protein Isoforms; D006180:Proton-Translocating ATPases; D034741:RNA, Small Interfering; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D025262:Vacuolar Proton-Translocating ATPases; C458319:ATP6AP2 protein, human; D000093342:Prorenin Receptor; C583530:ATP6AP2 protein, mouse