Anti-Progesterone Receptor (Ser294) Antibody

There is accumulating evidence to suggest that progesterone plays an essential role in the regulation of growth and differentiation of mammary glands and thus may play a key role in breast cancer (Edwards, 2005). The biological response to progesterone is mediated by two distinct forms of the human progesterone receptor (PR-A and PR-B forms). In most cell contexts, the B form functions as a transcriptional activator, whereas the A form functions as a transcriptional inhibitor of steroid hormones (Attia et al., 2000; Lin et al., 2003). Recently it has been demonstrated that there is differential hormone dependent regulation of the phosphorylation of the A and B forms of the receptor (Clemm et al., 2000) . Treatment of T47D breast cancer cells with progestin agonist increases the phosphorylation of Ser-190 and Ser-294 with different kinetics. These phosphorylation events may differentially affect the transcriptional activity of the receptor.