Prohibitin probably acts as a holdase/unfoldase for the stabilization of newly synthesized mitochondrial proteins. Has an antiproliferative activity. Regulates replicative life span. 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 9690 molecules/cell in log phase SD medium. PHB1 subunits are targeted to mitochondria by an unconventional non-cleavable targeting sequence present at their N-terminus. Belongs to the prohibitin family.