Receptor tyrosine kinase binding ligands of the EGF family and activating several signaling cascades to convert extracellular cues into appropriate cellular responses (PubMed:3260329). Known ligands include EGF and TGFA/TGF-alpha (PubMed:3260329). Ligand binding triggers receptor homo- and/or heterodimerization and autophosphorylation on key cytoplasmic residues (By similarity). The phosphorylated receptor recruits adapter proteins like GRB2 which in turn activates complex downstream signaling cascades (By similarity). Activates at least 4 major downstream signaling cascades including the RAS-RAF-MEK-ERK, PI3 kinase-AKT, PLCgamma-PKC and STATs modules (By similarity). May also activate the NF-kappa-B signaling cascade (By similarity). ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Endocytosis and inhibition of the activated EGFR by phosphatases constitute immediate regulatory mechanisms. Moreover, inducible feedback inhibitors may constitute alternative regulatory mechanisms for the EGFR signaling. Binding of the ligand triggers homo- and/or heterodimerization of the receptor triggering its autophosphorylation. In response to EGF, translocated from the cell membrane to the nucleus via Golgi and ER. Endocytosed upon activation by ligand (By similarity). Phosphorylated. Autophosphorylates. Belongs to the protein kinase superfamily. Tyr protein kinase family. EGF receptor subfamily.