N-CoR and SMRT are non-DNA-binding co-repressors originally shown to be important for transcriptional repression by unliganded nuclear hormone receptors. These co-repressors can in fact confer repression on a variety of transcription factors, including AP-1, NF-κB, Pit-1 and STAT5. Kristen Jepsen and Michael Rosenfeld review recent studies that have shed light on co-repression by N-CoR and SMRT. The two proteins are components of a variety of multiprotein complexes that contain histone deacetylases (e.g. Rpd3p or Hda1p) — these appear to repress transcription by deacetylating lysine residues in the N-terminal tails of histones. Regulation seems to occur at several levels. Phosphorylation of the co-repressor can stimulate or block association with transcription factors, depending on the kinase, and vice versa. In addition, it can modulate the subcellular localization of the co-repressor and its ability to form distinct co-repressor complexes. The importance of these co-repressors for normal cell function is illustrated by human genetic...

You do not currently have access to this content.