Signaling by Nuclear Receptors

Nuclear receptors are a family of ligand-regulated transcription factors that are activated by steroid hormones, such as estrogen and progesterone, and various other lipid-soluble signals, including retinoic acid, oxysterols, and thyroid hormone (Mangelsdorf et al. 1995).Unlike most intercellular messengers, the ligands can cross the plasma membrane and directly interact with nuclear receptors inside the cell (Fig. 1), rather than having to act via cell surface Cytoplasm Nucleus Coactivators Coactivators Cytosolic effects Type I/III e.g., estrogen Type II (extracellular ligand) e.g., thyroid hormone Corepressors TRE/LXRE ERE ER HSP HSP ER