Description
Erythropoietin (Epo) binds to the Epo receptor (EpoR) on the surface of erythroid precursor cells, stimulating their proliferation, survival, and differentiation into mature red cells. The EPO receptor is a member of a family of cytokine receptors that includes receptors for prolactin, growth hormone, interleukins 2-7, granulocyte macrophage colony-stimulating factor, granulocyte colony- stimulating factor, leukemia inhibitory factor, thrompopoietin ligand, and ciliary neurotrophic factor. This family is characterized by regions of similarity in their extracellular and intracellular domains. The family is also characterized by a lack of an identifiable protein tyrosine kinase domain in their intracellular region. Activation of the receptors by ligand binding induces a cascade of signaling events including phosphorylation of the EPO receptor, activation of the JAK-STAT pathway, activation of PI3 kinase, and activation of the RAS- MAPK pathway