Insulin and Insulin-like Receptor Activators

Insulin receptors (IRs) and insulin-like growth factor receptors (IGFRs) are formed from two subunits, each of which is comprised of an extracellular α-subunit and a transmembrane β-subunit with intracellular tyrosine kinase activity. IR homodimers are activated by insulin and, in adults, mediate an increase in glucose uptake through upregulation of GLUT4 expression. Two isoforms of the IR exist: fetal IR-A and adult IR-B.

IGF1R homodimers are activated by IGF-I and IGF-II and ...