V-ATPases, or Vacuolar ATPases, are present in plasma membranes in a wide variety of cell types and organellar membranes where they carry out several important functions. Their most important roles include those played in maintaining pH homeostasis, synaptic transmission, coupled transport across membranes, acidifying the acrosome of the sperm, and tumor metastasis. The protein in itself, is a heteromultimeric one and is made up of several subunits. Structurally, the protein has two regions, one external to the membrane, which carries out the hydrolysis of ATP and one integral to the membrane, which carries out the proton translocation. The region integral to the membrane, also known as V0, is itself composed of at least five different subunits. The ATP6V0A2 gene codes for the a2 subunit of this protein.
The exact functions of the a2 subunit are less clear. But it is understood that this subunit is directly involved in protein transport and has also been shown to be involved in recruiting proteins which regulate vesicular trafficking. Recent research also shows that this subunit has an important role to play in the active functioning of the Golgi apparatus, specifically the glycosylation function, by controlling the Golgi pH.