Signalling by Steroid Receptors

Abstract

Steroid hormones such as oestrogens control a wide variety of functions important for cell homeostasis, proliferation, differentiation, and apoptosis. Their action is mediated by specific hormone receptors, oestrogen receptor (ER)‐α and ERβ, which belong to a large superfamily of nuclear receptors. Typically, ERs function as ligand‐activated transcription factors, binding to specific oestrogen response elements (EREs) within target gene promoters and initiating a downstream response. Ligand‐independent gene transcription can also occur via tethered interactions with activating protein 1 (AP‐1) and stimulating protein 1 (SP1) proteins. A third pathway has been identified, involving membrane‐initiated signalling. These pathways are not mutually exclusive with evidence of considerable crosstalk between them. This chapter focuses on recent developments related to our understanding of these ER‐signalling mechanisms.