Regulation of cell signalling cascades by steroid hormones.

Steroid hormones control a wide variety of cellular functions important for cell homeostasis, proliferation, differentiation, and apoptosis. Evidence collected in the last few years indicates that this regulation is mediated by a complex interface of direct control of gene expression (so-called "transcriptional" action, driven by receptors that are localized in cell nucleus) and by regulation of cell signaling/phosphorylation cascades ("extranuclear" action, mediated by receptors that are localized in close proximity to cellular membrane). Regulation of gene expression takes place via ligand-dependent receptor binding to target gene promoters as part of the preinitiation complex, which leads to chromatin remodeling and ultimately regulates the rate of gene expression. Steroid-mediated regulation of cell signaling does not depend on gene transcription or protein biosynthesis. The molecular mechanism of this phenomenon is not fully understood. This review will focus on recent developments related to our understanding of the molecular mechanism of the extranuclear action of steroid hormones.