PGC-1β Background Information Transcription factors exert their effects by associating with coactivator or corepressor proteins. The coactivator complexes are thought to be constitutively active, requiring only proper positioning in the genome to initiate transcription. Coactivators include the steroid receptor coactivator (SRC) and CREB binding protein (CBP) families that contain histone acetyltransferase (HAT) activity, which modifies chromatin structure. PPAR gamma coactivator-1∫ (PGC-1∫), also known as PERC or PPARGC1B, functions as a transcriptional activator for NRF-1 (nuclear respiratory factor-1), ERå (estrogen receptor alpha) and GR (glucocorticoid receptor). Through its interaction with various receptors, PGC-1∫ is involved in the regulation of mitochondrial biogenesis events such as energy expenditure and non-oxidative glucose metabolism. Expressed throughout the body with the highest expression in brain, heart and skeletal muscle, PGC-1∫ is induced by insulin and repressed by saturated fatty acids. The gene encoding PGC-1∫ is polymorphic and variations in the expressed protein may contribute to the development of obesity.
