Abstract

Cell proliferation in response to growth factors is mediated by specific high affinity receptors. Ligand‐binding by receptors of the protein tyrosine kinase family results in the stimulation of several intracellular signal transduction pathways. Key signalling enzymes are recruited to the plasma membrane through the formation of stable complexes with activated receptors. These interactions are mediated by the conserved, non‐catalytic SH2 domains present in the signalling molecules, which bind with high affinity and specificity to tyrosine‐phosphorylated sequences on the receptors. The assembly of enzyme complexes is emerging as a major mechanism of signal transduction and may regulate the pleiotropic effects of growth factors.