Estrogen Receptor α (Tyr-537), Phosphospecific Antibody

Estrogen receptor α (ERα) is a member of the steroid receptor superfamily and its structure includes an N-terminal ligand-independent transactivation domain (AF-1), a highly conserved DNA binding domain, and a C-terminal ligand-dependent transactivation domain (AF-2) . AF-1 and AF-2 activate transcription independently and synergistically, and act in a promoter- and cell-specific manner. Phosphorylation at multiple sites provides an important mechanism to regulate ERα activity. Ser-104, Ser-106, Ser-118, and Ser-167 are located in the amino-terminal transcription activation function domain AF-1, and phosphorylation of these serine residues plays an important role in regulating ERα activity. In addition to these sites, phosphorylation of Tyr-537 has been implicated in maximal hormone binding, dimerization, and transcriptional activity. Tyr-537, located in the AF-2 domain, is phosphorylated by c-Src leading to nuclear export of ERα and degradation. Thus, a variety of phosphorylation events control ERα activity.

The antibody was cross-adsorbed to unphosphorylated ERα (Tyr-537) peptide before affinity purification using phospho-ERα (Tyr-537) peptide (without carrier) . This antibody detects several forms of ERα ranging from 66 to 35 kDa* on SDS-PAGE immunoblots of MCF-7 cells treated with pervanadate, and this reactivity is removed after alkaline phosphatase treatment. This sequence is well conserved in rat and mouse ERα, and is also well conserved in ERβ (Tyr-488) .