{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Epidermal growth factor receptor (EGFR) is the receptor for epidermal growth factor. It is a member of the ErbB family receptors, a subfamily of four closely related receptor tyrosine kinases: EGFR (ErbB-1 or HER1), HER-2 neu (ErbB-2), HER-3 (ErbB-3) and HER-4 (ErbB-4). EFFRs are single chain transmembrane glycoproteins consisting of an extracellular ligand binding domain, a transmembrane domain, a tyrosine kinase domain, and a tyrosine containing c-terminal tail. The binding of ligands to the extracellular domain causes the receptors to dimerize and activates the kinase domain. This activation phosphorylates the c-terminal tail and stimulates multiple downstream signal transduction pathways involved in cell growth and proliferation."}]}]}