Vacuolar ATPase accessory protein

Vacuolar ATPase accessory proteins are non-catalytic protein components required for the proper assembly, stability, and function of the vacuolar H^+-ATPase (V-ATPase) complex, a multi-subunit enzyme proton pump responsible for acidifying intracellular organelles and, in some specialized cells, the plasma membrane[6][7]. Key accessory proteins in mammals include ATP6AP1 (Ac45) and ATP6AP2 ((pro)renin receptor or PRR), which are essential for assembling the V-ATPase catalytic (V1) and membrane (V0) sectors and enabling proton translocation across biological membranes[5][6][7]. These accessory proteins are critical modulators of processes such as lysosomal degradation, autophagy, synaptic vesicle function, bone resorption, renal acid–base balance, and antigen processing[4][5][6]. Malfunction or mutations in V-ATPase accessory proteins are implicated in several pathologies, including osteopetrosis, renal tubular acidosis, neurodegeneration, infections, and cancer progression[5][6]. Current therapeutic research focuses on targeting V-ATPase function as a whole rather than its accessory proteins specifically; however, the accessory proteins represent potential future therapeutic targets due to their regulatory roles[5][6][7].

Other names

Ac45 (for ATP6AP1/Ac45)(pro)renin receptor (for ATP6AP2/PRR)V-ATPase accessory proteins

Modulation of V-ATPase assembly/function, Regulation of proton pumping, Indirect acidification of cellular compartments