8.A.107.  The V-type ATPase assembly factor, ATP6AP1 (ATP6AP1) Family 

Atp6ap1b functions to localize the V-ATPase to the plasma membrane where it regulates proton flux and cytoplasmic pH in humans and zebrafish (Gokey et al. 2015). It forms a complex with ATP6AP2 which serves the same function (Guida et al. 2018). It has been given the designation of the Vacuolar ATP synthase subunit S1 (ATP6S1) family in the conserved domain database, CDD.



Gokey, J.J., A. Dasgupta, and J.D. Amack. (2015). The V-ATPase accessory protein Atp6ap1b mediates dorsal forerunner cell proliferation and left-right asymmetry in zebrafish. Dev Biol 407: 115-130.

Guida, M.C., T. Hermle, L.A. Graham, V. Hauser, M. Ryan, T.H. Stevens, and M. Simons. (2018). ATP6AP2 functions as a V-ATPase assembly factor in the endoplasmic reticulum. Mol. Biol. Cell mbcE18040234. [Epub: Ahead of Print]

Rujano, M.A., M. Cannata Serio, G. Panasyuk, R. Péanne, J. Reunert, D. Rymen, V. Hauser, J.H. Park, P. Freisinger, E. Souche, M.C. Guida, E.M. Maier, Y. Wada, S. Jäger, N.J. Krogan, O. Kretz, S. Nobre, P. Garcia, D. Quelhas, T.D. Bird, W.H. Raskind, M. Schwake, S. Duvet, F. Foulquier, G. Matthijs, T. Marquardt, and M. Simons. (2017). Mutations in the X-linked cause a glycosylation disorder with autophagic defects. J Exp Med 214: 3707-3729.

Schoonderwoert, V.T. and G.J. Martens. (2002). Structural gene organization and evolutionary aspects of the V-ATPase accessory subunit Ac45. Biochim. Biophys. Acta. 1574: 245-254.


TC#NameOrganismal TypeExample

ATP6AP1 (ATP6IP1, ATP6S1, VATPS1), an accesory protein that functions in a complex with ATP6AP2 to facilitate assembly of V-type ATPases in eukaryotes (Guida et al. 2018).

ATP6AP1 of Homo sapiens


ATP6AP1 pf 459 aas and 2 TMSs, N- and C-terminal.  Functions together with ATP6AP2 as an assemby factor for V-type ATPases in the plasma membrane ().

ATP6AP1 of Danio rerio (Zebrafish) (Brachydanio rerio)


AC45 or ATP6AP1 chaparone protein of the V-type ATPase (Schoonderwoert and Martens 2002). ATP6AP2 mutations impair protein stability and the interaction with ATP6AP1, a constituent of the V0-ATPase assembly complex. Missense mutations in ATP6AP2 lead to impaired V-ATPase assembly and subsequent defects in glycosylation and autophagy (Rujano et al. 2017).

AC45 of Drosophila melanogaster


V-type ATPase accessory protein, Vha-19, of 451 aas and 2 TMSs, N- and C-terminal. 

Vha-19 of Caenorhabditis elegans


Uncharacterized protein of 412 aas and 2 TMSs, N- and C-terminal.

UP of Parasteatoda tepidariorum (common house spider)


TC#NameOrganismal TypeExample

Uncharacterized protein of 286 aas and 1 C-terminal TMS.

UP of Aspergillus niger


Uncharacterized protein of 270 aas and 2 TMSs, N- and C-terminal.

UP of Mycena chlorophos


Uncharacterized protein of 266 aas and 2 TMSs, N- and C-terminal.

UP of Lichtheimia ramosa


TC#NameOrganismal TypeExample

Uncharacterized protein of 713 aas and 2 TMSs, N- and C-terminal.

UP of Planoprotostelium fungivorum


Uncharacterized protein of 297 aas and 2 TMSs, N- and C-terminal.

UP of Tieghemostelium lacteum


Uncharacterized protein of 316 aas and 2 TMSs, N- and C-terminal.

UP of Phytophthora sojae (Soybean stem and root rot agent) (Phytophthora megasperma f. sp. glycines)


TC#NameOrganismal TypeExample

Uncharacterized protein of 319 aas and 2 TMSs, N- and C-terminal.

UP of Camelina sativa