coactivatorscorepressors

Coactivators and corepressors are regulatory proteins that modulate the activity of transcription factors, which are proteins that control gene expression by binding to specific DNA sequences. These regulatory proteins interact with transcription factors to either enhance (coactivators) or suppress (corepressors) their ability to activate or repress gene transcription.

Coactivators are proteins that enhance the activity of transcription factors by facilitating the recruitment of the basal transcription machinery to the promoter region of a gene. They often contain domains that interact with other proteins, such as histone acetyltransferases (HATs), which modify histones to relax DNA and make it more accessible to transcription factors. Examples of coactivators include CREB-binding protein (CBP) and p300.

Corepressors, on the other hand, suppress the activity of transcription factors by preventing the recruitment of the basal transcription machinery or by facilitating the recruitment of repressor complexes. They often contain domains that interact with histone deacetylases (HDACs), which modify histones to compact DNA and make it less accessible to transcription factors. Examples of corepressors include NCoR (nuclear receptor corepressor) and SMRT (silencing mediator of retinoic acid and thyroid hormone receptor).

The interaction between transcription factors and coactivators or corepressors is dynamic and can be influenced by various factors, such as cellular context, post-translational modifications, and the presence of other regulatory proteins. This regulatory mechanism is crucial for maintaining proper gene expression patterns and cellular function.