Expanding functional diversity of the coactivators.

Nuclear receptors (NR) function as ligand-regulated transcription factors that transduce hormonal signals from steroid hormones and other lipophillic ligands. NR-mediated transcription depends on coactivators, a diverse group of proteins that affect the transcriptional machinery in a variety of ways such as via their associated enzymatic activities as histone acetyltransferases, methyltransferases, ubiquitin ligases or as agents that integrate signaling via kinase-signaling pathways. Coactivators have various roles in the transcriptional process (i) as molecules that influence key points in the different stages of transcription, (ii) as integrators of environmental growth-factor and steroid-hormone signals, and (iii) as agents of carcinogenesis.