Component of the MICOS complex, a large protein complex of the mitochondrial inner membrane that plays crucial roles in the maintenance of crista junctions, inner membrane architecture, and formation of contact sites to the outer membrane (PubMed:25997101, PubMed:27623147, PubMed:32567732). Constituent of mature MICOS complex, it is required for the formation of cristae junction (CJ) and maintenance of cristae morphology (PubMed:25997101, PubMed:27623147, PubMed:32567732). Required for the incorporation of MICOS10/MIC10 into the MICOS complex (PubMed:25997101, PubMed:27623147).