Figure 2.
Insulin induces receptor autophosphorylation and association of IRS molecules, which then recruit PI3K to the plasma membrane. Subsequent production of PI(3,4,5)P3 allows signaling downstream of PI3K. PKB translocates to the plasma membrane where it is activated via phosphorylation by PDK1/2. GSK-3α/β is subsequently phosphorylated and inactivated by PKB thus preventing phosphorylation of down-stream substrates such as glycogen synthase. Glycogen synthase is activated by dephosphorylation by protein phosphatase 1 (PP1).