Receptor tyrosine kinase which mediates actions of insulin. May be required for forelimb regeneration. ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Autophosphorylation activates the kinase activity. Tetramer of 2 alpha and 2 beta chains linked by disulfide bonds. The alpha chains contribute to the formation of the ligand-binding domain, while the beta chains carry the kinase domain (By similarity). Localized mainly to the envelope in oocytes. Localized to the animal hemisphere during early embryonic cleavage. Expressed during organogenesis in regions of ecto- and mesodermic origins. Expressed in the entire encephalon, the otic and optic vesicles, the gills, the somites and the pronephric tubules of the embryo. Also found in adult liver, muscle and regenerated forelimbs. Expressed both maternally and zygotically. Weakly expressed in embryos through gastrulation and neurulation. Expressed in the tailbud stage and in older tadpoles. Autophosphorylated on tyrosine residues in response to insulin. Belongs to the protein kinase superfamily. Tyr protein kinase family. Insulin receptor subfamily.