Figure 1.

Canonical insulin signaling pathway. Binding of insulin to insulin receptor (IR) triggers phosphorylation of IRS, which in turn phosphorylates PI3K. Activated PI3K recruits PDK1 to the cell membrane. Akt is phosphorylated by PDK1 (on T308) and mTORC2 (on S473). Activated Akt targets a wide range of downstream targets including TSC2, GSK3β, and FoxO1 to regulate essential metabolic events. Insulin binding to its receptor also activates SHC adaptor proteins which target RAS and ERK to promote cell proliferation. Activated IR can also translocate to cell nucleus to induce the expression of genes that play role in lipid metabolism and protein synthesis. ECM, extracellular matrix.