The steroid hormones and their receptors are involved in the regulation of eukaryotic gene expression and affect cellular proliferation and differentiation in target tissues. Depending on the isoform, progesterone receptor functions as transcriptional activator or repressor (By similarity). Ligand-dependent transdominant repressor of steroid hormone receptor transcriptional activity including repression of its isoform B, MR and ER. Transrepressional activity may involve recruitment of corepressor NCOR2. Transcriptional activator of several progesteron-dependent promoters in a variety of cell types. Involved in activation of SRC-dependent MAPK signaling on hormone stimulation. Interacts with SMARD1 and UNC45A. Interacts with CUEDC2; the interaction promotes ubiquitination, decreases sumoylation, and represses transcriptional activity. Interacts with PIAS3; the interaction promotes sumoylation of PR in a hormone-dependent manner, inhibits DNA-binding, and alters nuclear export. Interacts with SP1; the interaction requires ligand-induced phosphorylation on Ser-349 by ERK1/2-MAPK. Interacts with PRMT2. Isoform A interacts with NCOR2. Isoform B (but not isoform A) interacts with NCOA2 and NCOA1. Isoform B (but not isoform A) interacts with KLF9. Interacts with GTF2B (By similarity). Nucleoplasmic shuttling is both hormone- and cell cycle-dependent. On hormone stimulation, retained in the cytoplasm in the G(1) and G(2)/M phases (By similarity). Expressed in mammary gland and uterus. Composed of three domains: a modulating N-terminal domain, a DNA-binding domain and a C-terminal ligand-binding domain. Phosphorylated on multiple serine sites. Several of these sites are hormone-dependent. Phosphorylation on Ser-303 occurs preferentially on isoform B, is highly hormone-dependent and modulates ubiquitination and sumoylation on Lys-392. Phosphorylation on Ser-303 and Ser-349 also requires induction by hormone. Basal phosphorylation on Ser-200 and Ser-404 is increased in response to progesterone and can be phosphorylated in vitro by the CDK2-A1 complex. Increased levels of phosphorylation on Ser-404 also in the presence of EGF, heregulin, IGF, PMA and FBS. Phosphorylation at this site by CDK2 is ligand-independent, and increases nuclear translocation and transcriptional activity. Phosphorylation at Ser-303, but not at Ser-200, is impaired during the G(2)/M phase of the cell cycle. Phosphorylation on Ser-349 by ERK1/2 MAPK is required for interaction with SP1 (By similarity). Sumoylation is hormone-dependent and represses transcriptional activity. Sumoylation on all three sites is enhanced by PIAS3. Desumoylated by SENP1. Sumoylation on Lys-392, the main site of sumoylation, is repressed by ubiquitination on the same site, and modulated by phosphorylation at Ser-303 (By similarity). Ubiquitination is hormone-dependent and represses sumoylation on the same site. Promoted by MAPK-mediated phosphorylation on Ser-303 (By similarity). Palmitoylated by ZDHHC7 and ZDHHC21. Palmitoylation is required for plasma membrane targeting and for rapid intracellular signaling via ERK and AKT kinases and cAMP generation (By similarity). Belongs to the nuclear hormone receptor family. NR3 subfamily.