Nuclear receptor coactivator that directly binds nuclear receptors and stimulates the transcriptional activities in a hormone-dependent fashion. Coactivates expression in an agonist- and AF2-dependent manner. Involved in the coactivation of different nuclear receptors, such as for steroids (GR and ERs), retinoids (RARs and RXRs), thyroid hormone (TRs), vitamin D3 (VDR) and prostanoids (PPARs). Probably functions as a general coactivator, rather than just a nuclear receptor coactivator. May also be involved in the coactivation of the NF-kappa-B pathway. May coactivate expression via a remodeling of chromatin and its interaction with histone acetyltransferase proteins. Involved in placental, cardiac, hepatic and embryonic development. Monomer and homodimer. Interacts in vitro with the basal transcription factors GTF2A and TBP, suggesting an autonomous transactivation function. Interacts with NCOA1, CRSP3, RBM14, the histone acetyltransferase proteins EP300 and CREBBP, and with methyltransferase proteins NCOA6IP and PRMT2 (By similarity). Interacts with RBM39. Component of the MLL2/3 complex (also named ASCOM complex), at least composed of KMT2D/MLL2 or KMT2C/MLL3, ASH2L, RBBP5, WDR5, NCOA6, DPY30, KDM6A, PAXIP1/PTIP, PAGR1 and alpha- and beta-tubulin (By similarity). Interacts with ZNF335; may enhance ligand-dependent transcriptional activation by nuclear hormone receptors (By similarity). Widely expressed. High expression in testis and weak expression in small intestine. Expressed at 9 dpc in placenta and at weaker level in uterus. High expression in neural tube and in CNS throughout development. High expression in sensory ganglia and retina from 11 dpc. In the alimentary tract and olfactory epithelium expression was seen from 13 dpc. Strong expression present in liver and kidney, from 11 dpc and 13 dpc respectively, and then expression decreased at later stages of development. Moderate expression in lung from 13 dpc, while it decreases during postnatal life. Strong expression in thymus from 15 dpc onwards, and in spleen from 17 dpc and during early postnatal life, then, the expression decreases. Contains two Leu-Xaa-Xaa-Leu-Leu (LXXLL) motifs. Only motif 1 is essential for the association with nuclear receptors. Phosphorylated. Acts as a dominant negative repressor.