Steroid hormone receptors (SRs) are ligand-activated transcription factors and sensors for
growth factor–initiated signaling pathways in hormonally regulated tissues, such as the
breast or prostate. Recent discoveries suggest that several protein kinases are rapidly
activated in response to steroid hormone binding to cytoplasmic SRs. Induction of rapid
signaling upon SR ligand binding ensures that receptors and coregulators are appropriately
phosphorylated as part of optimal transcription complexes. Alternatively, SR-activated …