BSC 300 Lecture Notes - Lecture 24: Mitogen-Activated Protein Kinase, Insulin Receptor Substrate, Ras Subfamily
Document Summary
Protein-tyrosine phosphorylation as a mechanism for signal transduction. Protein-tyrosine kinases phosphorylate tyrosine residues on target proteins. Over 90 different protein-tyrosine kinases are encoded by the human genome. Protein-tyrosine kinases regulate cell growth, division, differentiation, survival and migration. Receptor tyrosine kinases (rtks) are cell surface receptors of the protein-tyrosine kinase family encoded by more than 60 rtk genes in the human genome. Phosphorylated tyrosines are bound by diverse proteins that contain docking domains that recognize the phosphorylated tyrosines. The most well-studied docking proteins contain one of two domains: the sh2 domains (src homology): over 100 in our genome, the ptb domains (phosphotyrosine binding): Specificity of interaction is determined by as sequences immediately adjacent to the phosphor-tyrosine. Rtk activation as a mechanism for signal transduction. Cells contain numerous proteins with sh2 or ptb domains that bind to phosphorylated tyrosine residues. Adapter proteins contain additional interaction domains that recruit other proteins to the activated receptor.