NCOA2/GRIP1 (nuclear receptor coactivator 2/glucocorticoid receptor-interacting protein 1 (GRIP1)) is a 159 kD member of the p160/steroid receptor coactivator family containing a nuclear localization sequence, bHLH, and PAS domain. Two isoforms of this protein have been reported. NCOA/GRIP1 is expressed in the cytoplasm and translocated into the nucleus upon phosphorylation. This protein is highly expressed in the placenta, skeletal muscle, uterus with lower expression in B cells, lymphocytes, and some tumors. NCOA/GRIP1 has histone acetyltransferase activity, and is a transcriptional coactivator for steroid and nuclear hormone receptor. This protein mediates ligand-independent nuclear translocation and activates the CAR receptor in response to phenobarbital. This protein is modified by phosphorylation. NCOA/GRIP1 forms a multisubunit coactivation complex with NCOA3, IKKA, IKKB, IKBKG and histone acetyltransferase protein CREB binding protein and has also been shown to interact with HIF1A, APEX, NR3C1, and CAR. The Poly6090 antibody recognizes the N-terminal region of human NCOA2/GRIP1 and has been shown to be useful for Western blotting.