Scaffold protein that participates in the c-ring assembly of mitochondrial ATP synthase (F(1)F(0) ATP synthase or complex V) by facilitating the membrane insertion and oligomer formation of the subunit c/ATP5MC3 (PubMed:33753518). Participates in the incorporation of the c-ring into vestigial complexes (PubMed:33753518). Additionally influences the incorporation of subunits MT-ATP6, MT-ATP8, ATP5MJ, and ATP5MK in the ATP synthase (PubMed:33753518). Interacts with the core subunits NDUFAF1, ECSIT and ACAD9 of the MCIA complex (PubMed:33753518). Interacts with ATP5MC3, NDUFC2, TMEM70, MT-ND2 AND MT-ND3 (PubMed:33753518). Belongs to the TMEM242 family. Extended N-terminus.