Insulin signal transduction: the role of protein phosphorylation

Recent evidence suggests that the mechanism of insulin action depends in part on protein phosphorylation on tyrosine residues. A cascade of phosphorylation/dephosphorylation reactions is proposed to modulate multiple enzymes involved in metabolism, protein synthesis, and cell growth. Direct evidence is presented for the phosphorylation of myelin basic protein and microtubule-associated protein 2 on tyrosine residues by the insulin receptor.