NCOA 4 ( Nuclear Receptor Coactivator 4 )

NCOA4 is involved in the androgen receptor signaling pathway and in the development of the male gonade. It is a ligand-dependent associated protein for the androgen receptor (AR), that functions as coactivator to enhance AR transcriptional activity (7-10 fold in human prostate cancer cells) and protein stability. NCOA4 also enhances the agonist activity of anti-androgens in human prostate cancer cells (3-30 fold in the prostate cancer cell line DU145), with relevant implications for hormonal treatment of prostate cancer. Albeit to a lesser degree (up to 2-fold), NCO4 also enhances transcription activity of other steroid receptors, such as glucocorticoid receptor (GR), progesterone receptor (PR) and oestrogen receptor (ER). In addition to the interaction with steroid hormone receptors, NCOA4 functions as coactivator of peroxisome proliferator-activated receptor gamma (PPARG). PPARG is a peroxisome proliferatoractivated receptor and as such belongs to the nuclear hormone receptor superfamily. PPARG is highly expressed in adipose tissue (were it is involved in adipogenesis and in the regulation of adipocyte-specific genes), as well as in other human tissues. Interestingly, PPARG is rearranged with PAX8 in a subset of follicular thyroid tumors.