Progesterone receptor (PR) is a member of the steroid/thyroid hormone-retinoid receptor superfamily of ligand-activated nuclear transcription factors. Progesterone receptor plays a vital role in female reproductive tissue development, differentiation, and maintenance.
Progesterone receptor is able to bind to a large number and variety of ligands that elicit a broad range of transcriptional responses ranging from full agonism to full antagonism and numerous mixed profiles inbetween. Progesterone receptor, such as progesterone, induces conformation changes in PR ligand binding domain (LBD), thus mediates subsequent gene regulation cascades.
In humans, the biological response to progesterone is mediated by two distinct forms of the progesterone receptor (human PR-A and PR-B).