Signal Transduction Mechanism of Insulin and Insulin-Like Growth Factor-1

Abstract

Insulin and insulin-like growth factor-1(IGF-1) are two structurally related hormones which produce similar biological activities such as metabolic and growth promoting actions. Their receptors, insulin and IGF-1 receptors, also share similarities in both structure and functions such as tyrosine- specific protein kinase. We identified insulin receptor substrate-1 (IRS-1) as a common substrate for insulin and IGF-1 receptor tyrosine kinases. We generated IRS-1 knockout mice and showed that IRS-1plays a physiological role in signal transduction and biological actions of insulin and IGF-1. We also identified pp190 (IRS-2) as an alternative substrate for IRS-1.