Western blot of whole cell T-47D lysate prepared from cells that had been incubated in the presence of the synthetic progestin agonist R5020 (500 nM) showing specific immunolabeling of the ~90k PGR-A isoform and the ~120 PGR-B isoform of the PGR phosphorylated at Ser294. The immunolabeling is blocked by the phosphopeptide used as the antigen (not shown).
This gene encodes a member of the steroid receptor superfamily. The encoded protein mediates the physiological effects of progesterone, which plays a central role in reproductive events associated with the establishment and maintenance of pregnancy. This gene uses two distinct promotors and translation start sites in the first exon to produce two isoforms, A and B. The two isoforms are identical except for the additional 165 amino acids found in the N-terminus of isoform A only, and mediate their own response genes and physiologic effects with little overlap. The location of transcription initiation for isoform B has not been clearly determined. [provided by RefSeq