Insulin-like growth factor I receptor: Structure, signal transduction, and function

In this review, we have presented evidence that points to a central role for the IGF-I receptor in the cell. These findings are that 1) the receptor is expressed by virtually every tissue and cell line; 2) cells in culture require IGFs (or large concentrations of insulin) to survive and proliferate; and 3) targeted disruption of the IGF-I receptor gene results in a lethal phenotype. The spectrum of pathological conditions in which IGF-I receptor function is compromised ranges from metabolic conditions, such as nutritional status and diabetes, to cancer and regenerative processes. Understanding the basic molecular and cellular mechanisms involved in IGF-I receptor action will undoubtedly help us design strategies to restore normal receptor function in those disease states in which it is implicated.