 Nuclear receptors may bind specifically to a number of coregulator proteins, and thereby influence cellular mechanisms of signal transduction both directly, as well as indirectly.Binding of agonist ligands (see section below) to nuclear receptors induces a conformation of the receptor that preferentially binds coactivator proteins.These proteins often have an intrinsic histone acetyltransferase (HAT) activity, which weakens the association of histones to DNA, and therefore promotes gene transcription.