Activation of PPARγ coactivator-1 through transcription factor docking

Transcriptional coactivators have been viewed as constitutively active components, using transcription factors mainly to Localize their functions. Here, it is shown that PPAR gamma coactivator-1 (PGC-1) promotes transcription through the assembly of a complex that includes the histone acetyltransferases steroid receptor coactivator-1 (SRC-1) and CREB binding protein (CBP)/p300. PGC-1 has a Low inherent transcriptional activity when it is not bound to a transcription factor. The docking of PGC-1 to peroxisome proliferator-activated receptor gamma (PPAR gamma) stimulates an apparent conformational change in PGC-1 that permits binding of SRC-1 and CBP/p300, resulting in a Large increase in transcriptional activity. Thus, transcription factor docking switches on the activity of a coactivator protein.