TARGETS OF ACTIVATED STEROID-HORMONE RECEPTORS - BASAL TRANSCRIPTION FACTORS AND RECEPTOR INTERACTING PROTEINS

Steroid hormone receptors constitute a family of inducible transcripti on factors that mediate the multifold effects of steroids on developme nt, reproduction, proliferation, and cellular homeostasis, Activation through the binding of the cognate hormone enables the receptors to bi nd with high affinity to specific response elements in the promoters o f target genes, resulting in stimulation or repression of transcriptio n. While protein-protein interactions were early postulated to play an important role in the mechanism through which steroid hormone recepto rs exert their effects on transcription initiation, recent research ha s revealed a number of potential targets within the basal transcriptio n machinery. Moreover, aided by the development of protein-protein int eraction screening techniques, a rapidly increasing number of factors has been identified which associate with hormonally activated receptor s and may be involved in the transactivation process. This review summ arizes the basal transcription factors and cofactors which are targete d by steroid hormone receptors, describes their structure and properti es, and discusses possible mechanisms.