Estrogen action and cytoplasmic signaling cascades. Part I: membrane- associated signaling complexes James H. Segars and Paul H. Driggers

), estrogen receptors αand β(ERα, ER β). These receptors function as ligand-dependent transcription factors to increase genetranscription from promoters by direct binding of thereceptor to specific DNAtarget sequences, designatedestrogen response elements (EREs). Association ofreceptors with the gene transcription machineryinvolves essential coregulatory proteins thatcontribute to estrogen action and that can enhance orrepress ER action (see Refs [1–3]). The importance ofthis signaling pathway