Nuclear receptors, many of which undergo a major conformational change upon
binding specific ligand, belong to a superfamily of proteins that bind to
specific DNA sequences and control gene transcription. They regulate the as
sembly of a transcriptional preinitiation complex at the promoter of target
genes and modulate their expression in response to ligand. In particular,
nuclear receptors repress or stimulate transcription by recruiting corepres
sor or co-activator proteins, in addition to directly contacting the basal
transcription machinery. In this review, we discuss recent progress in stud
ies of these transcriptional coregulators of nuclear receptors.