Insulin receptor binds insulin and has a tyrosine-protein kinase activity. It also has catalytic activity: ATP + a protein tyrosine = ADP + proteintyrosine phosphate. Tetramer of 2 alpha and 2 beta chains linked by disulfidebonds. The alpha chains contribute to the formation of the ligand-binding domain, while the beta chains carry the kinase domain. Interacts with SORBS1 but dissociates from it following insulin stimulation. [subcellular location] Type I membrane protein. Belongs to the Tyr protein kinase family. Insulin receptor subfamily.