The V-ATPases (or V1V0-ATPase) and A-ATPases (or A1A0-ATPase) are each composed of two linked complexes: the V1 or A1 complex contains the catalytic core that hydrolyses/synthesizes ATP, and the V0 or A0 complex that forms the membrane-spanning pore. The V- and A-ATPases both contain rotary motors, one that drives proton translocation across the membrane and one that drives ATP synthesis/hydrolysis [11309608, 15629643, 15168615]. The V- and A-ATPases more closely resemble one another in subunit structure than they do the F-ATPases, although the function of A-ATPases is closer to that of F-ATPases.
This entry represents subunit C from the A0 complex of A-ATPases, and subunits C and D from the V0 complex of V-ATPases, all of which are involved in the translocation of protons across a membrane. There is more than one type of D subunit in V-ATPases, where the D1 subunit is ubiquitous, while the D2 subunit has limited tissue expressivity, possibly to account for differential functions, targeting or regulation of V-ATPase activity .
More information about this protein can be found at Protein of the Month: ATP Synthases.