Mediator Complex Subunit 4 (MED4)

MED4 is a component of the vitamin D receptor-interacting protein (DRIP) complex which functions as a nuclear receptor coactivator. The DRIP complex is capable of activating nuclear receptors in a ligand-dependent manner.By SDS-PAGE analysis of nuclear extract-depleted B cells bound to VDR LBD in the presence of vitamin D, followed by mass spectrometry, micropeptide sequence analysis, and EST database searching, Rachez et al. (1999) identified cDNAs encoding 13 DRIPs, including DRIP36. They noted that DRIP36 is nearly identical to the p34 subunit of the mouse """mediator.""" Rachez et al. (1999) concluded that transcriptional regulation by nuclear hormone receptors appears to involve the recruitment of coactivator or repressor complexes or subcomplexes composed of shared polypeptides.