PHB2,also named as BAP,REA,D-prohibitin,BAP37 and Prohibitin-2,belongs to the prohibitin family. It acts as a mediator of transcriptional repression by nuclear hormone receptors via recruitment of histone deacetylases. PHB2 functions as an estrogen receptor (ER)-selective coregulator that potentiates the inhibitory activities of antiestrogens and represses the activity of estrogens. It competes with NCOA1 for modulation of ER transcriptional activity. PHB2 is probably involved in regulating mitochondrial respiration activity and in aging.