Receptor tyrosine kinases and their targets.

One of the ways in which higher eukaryotes receive messages from the environment is via cell surface receptor tyrosine kinases. These are transmembrane proteins with an extracellular binding domain that specifies the growth factor with which it will interact, and an intracellular domain that encodes the tyrosine kinase. The mechanism by which receptor tyrosine kinases direct intracellular signal relay appears to involve receptor autophosphorylation that permits the stable binding of SH2 domain containing signal transduction enzymes. Some of the more recent advances are summarized in this review.