Prohibitin probably acts as a holdase/unfoldase for the stabilization of newly synthesized mitochondrial proteins. The mitochondrial prohibitin complex consists of two subunits (PHB1 and PHB2), assembled into a membrane-associated ring-shaped supercomplex of approximately 1 mDa. The N-terminus is blocked. Present with 2850 molecules/cell in log phase SD medium. Mitochondrial targeting of PHB2 is ensured by a bipartite non-cleavable presequence at the N-terminus. Belongs to the prohibitin family.