Rabbit Anti-Glucocorticoid Receptor Antibody from MyBioSource.com

Glucocorticoid hormones control cellular proliferation and metabolism through their association with the glucocorticoid receptor (GR), a member of the intracellular receptor superfamily of transcriptional regulatory proteins (1). The GR zinc binding region (ZBR) harbors the DNA binding and protein dimerization functions of GR and is essential for regulation of all known GR target genes. In the absence of hormone, GR is localized to the cytoplasm in association with a molecular chaperone complex that interacts with the GR ligand binding domain (LBD). On hormone binding, GR releases the chaperone complex and translocates to the cell nucleus to associate with specific DNA sequences termed glucocorticoid response elements (GREs), and increases or represses transcription of specific target genes (2). It was demonstrated that GR-mediated transcriptional activation is modulated by phosphorylation (3-5). Although GR can be phosphorylated in the absence of hormone, it is further phosphorylated in conjunction with agonist (but not antagonist) binding. It has been suggested that hormone-dependent phosphorylation of GR may determine target promoter specificity, cofactor interaction, strength and duration of receptor signaling, and receptor stability as well as receptor subcellular localization (3). Ser203 and Ser211 of human GR (corresponding to Ser224 and Ser232 of mouse GR) are shown to be phosphorylated to a greater extent in the presence of hormone. The cyclin-dependent kinases may be potential kinases that modify Ser203 and Ser211. Biochemical fractionation studies following hormone treatment indicated that the Ser203-phosphorylated form of the receptor was predominantly cytoplasmic, whereas Ser211-phosphorylated GR was found in the nucleus (3). Thus, Ser211 phosphorylation is a biomarker for activated GR in vivo