Mitochondrial membrane ATP synthase (F(1)F(0) ATP synthase or Complex V) produces ATP from ADP in the presence of a proton gradient across the membrane which is generated by electron transport complexes of the respiratory chain. F-type ATPases consist of two structural domains, F(1) - containing the extramembraneous catalytic core and F(0) - containing the membrane proton channel, linked together by a central stalk and a peripheral stalk. During catalysis, ATP synthesis in the catalytic domain of F(1) is coupled via a rotary mechanism of the central stalk subunits to proton translocation (PubMed:29917077). ATP5MK is a minor subunit of the mitochondrial membrane ATP synthase required for dimerization of the ATP synthase complex and as such regulates ATP synthesis in the mitochondria (PubMed:21345788, PubMed:29917077). Component of the ATP synthase complex/complex V which is composed of ATP5PB, ATP5MC1, ATP5F1E, ATP5PD, ATP5ME, ATP5PF, ATP5MF, MT-ATP6, MT-ATP8, ATP5F1A, ATP5F1B, ATP5F1D, ATP5F1C, ATP5PO, ATP5MG, ATP5MK and ATP5MJ (By similarity). The ATP synthase complex/complex V exists as a monomeric and a dimeric supercomplex that helps shape mitochondrial cristae to optimize proton flow (PubMed:29917077). Transactivated by SBP1. The disease is caused by variants affecting the gene represented in this entry.