Question

How do you expect a mutation on the CBP biding site that inhibits CBP binding would affect the lac operon in the presence or absence of glucose?

Answer 1

CREB binding protein (CBP) was originally identified for its ability to interact strongly with the transcription factor . CBP and the closely related protein p300 were identified as essential cofactors for a number of nuclear transcription factors, including the AP-1 complex, several components of the basal transcriptional machinery (TBP and TFIIB), other histone acetyltransferases (SRC-1, ACTR, and P/CAF), viral oncoproteins (E1A, large T antigen, and Tax), and developmental proteins (GATA-1, EKLF, myo-D, MEF-2, and Pit-1)

CREB Binding Protein Recruitment to the Transcription Complex Requires Growth Factor–Dependent Phosphorylation of Its GF Box

CBP is thought to bind to nuclear transcription factors in both a phosphorylation-dependent and -independent manner. CREB binding to CBP/p300, for example, requires phosphorylation at serine 133. While this CREB phosphorylation event is absolutely required for CBP recruitment to the transcription complex, it is less clear whether phosphorylation of other transcription factors affects their ability to recruit CBP/p300. For instance, phosphorylation of the amino-terminus of c-Jun (serines 63 and 73) may enhance CBP binding but other in vitro data do not necessarily support these findings Furthermore, although the pituitary-specific transcription factor Pit-1 is phosphorylated by a number of intracellular signaling pathways, recruitment of CBP does not appear to require Pit-1 phosphorylation .