Insulin Receptor (胰岛素受体)

Insulin receptor (IR), a phylogenetically ancient tyrosine kinase receptor, is a large cell surface glycoprotein that concentrates insulin at the site of action and also initiates responses to insulin. The receptor is a disulfide-linked oligomer comprised of two alpha and two beta subunits. The insulin receptor exists in two isoforms, IR-A and IR-B, expressed in different relative abundance in the various organs and tissues. The two IR isoforms have similar binding affinity for insulin but different affinity for insulin-like growth factor (IGF)-2 and proinsulin, which are bound by IR-A but not IR-B.

The insulin receptor has a crucial role in controlling glucose homeostasis, regulating lipid, protein and carbohydrate metabolism, and modulating brain neurotransmitter levels. Insulin receptor dysfunction has been associated with many diseases, including diabetes, cancer and Alzheimer's disease.