This receptor probably binds an insulin related protein and has a tyrosine-protein kinase activity. ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] 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). Highly expressed in the brain and ovary. Belongs to the protein kinase superfamily. Tyr protein kinase family. Insulin receptor subfamily.