p-EpoR Antibody (Tyr 456)-R: sc-20236-R

---

Erythropoiesis is regulated through the interaction of erythropoietin (Epo) with its receptor, EpoR, a member of the cytokine superfamily of receptors (1,2). The human EpoR is a 507 amino acid transmembrane protein that forms homodimers following erythropoietin activation (3) and is related to the interleukin 2 (IL-2) receptor b-chain subunit (IL-2Rb) (4,5). EpoR and IL-2Rb share 45% amino acid identity within the box 1 and box 2 domains of their cytoplasmic regions while their remaining cytoplasmic sequences are highly divergent (4). These conserved domains are both required and sufficient for mitogenesis and for coupling ligand binding to the induction of tyrosine phosphorylation (4,6). Epo and IL-3 stimulate activation of the Jak2 tyrosine kinase and induce tyrosine phosphorylation and activation of Stat5 (7). Epo or IL-3 stimulation induces binding of Stat5 to the tyrosine-phosphorylated EpoR or IL-3Rb subunit, respectively, in IL-3-dependent 32D cells expressing the EpoR (7). Tyr-454 is required for PTPN6 interaction, and Tyr-426 for PTPN11. Tyr-426 is also required for SOCS3 binding, but Tyr-454/Tyr-456 motif is the preferred binding site. (8)