Accessory component of the proton-transporting vacuolar (V)-ATPase protein pump involved in intracellular iron homeostasis. In aerobic conditions, required for intracellular iron homeostasis, thus triggering the activity of Fe(2+) prolyl hydroxylase (PHD) enzymes, and leading to HIF1A hydroxylation and subsequent proteasomal degradation. Necessary for endolysosomal acidification and lysosomal degradation . May be involved in Golgi homeostasis .
Subcellular locations: Cytoplasmic vesicle, COPI-coated vesicle membrane, Endoplasmic reticulum-Golgi intermediate compartment membrane, Endoplasmic reticulum membrane
Partial colocalization with GOLGB1.