Insulin Receptor, active Human Recombinant Kinase Protein

The insulin receptor kinase (IRK) is composed of two extracellular a-subunits (135 kDa), which contain the insulin-binding site, and two intracellular b-subunits (95 kDa), containing the protein tyrosine kinase domain. After insulin binding, the insulin-IRK complex internalizes into muscle and fat cells. The IRK substrates of IRS-1 and IRS-2 form complexes, through Src homology region 2 (SH2) domains, with docking molecules such as phosphoinositde-3-kinase (PI3K). The recruitment of PI3K in turn activates phosphoinositide-dependent kinases, which serve in the activation of protein kinase B (Akt) and atypical isoforms of protein kinase C (PKC). These activated kinases then phosphorylate downstream effectors, ultimately promoting the translocation of insulin-sensitive glucose transporter subtype 4 (GLUT-4) to the plasma membrane, to operate in the coordination of glucose metabolism. GenBank NM_000208