BIOL 331 Lecture Notes - Lecture 33: Insulin Receptor Substrate, Protein Kinase, Grb2
Document Summary
Cell signalling part 4: receptor protein - tyrosine kinases (rtks) Rtks possess tyrosine kinase activity within a domain of the receptor amino- acid chain. A conformational change induced by ligand binding activates the kinase activity. The kinase activity enhances its own activity through auto-phosphorylation of the receptor chain and phosphorylation of the receptor also creates docking sites for signalling molecules. Ligand-mediated (one ligand with 2 receptor-binding sites), or. Receptor-mediated dimerization (each receptor chain binds one ligand) Rtks possess a domain in the protein chain that functions as a tyrosine kinase on the cytoplasmic side. Function as docking sites for signalling molecules. Sh2 domain (src homology domain - 2) Sh3 domain (src homology domain - 3) Grb2 link activated receptors to signalling molecules. Stat (signal transducers and activators of transcription) Transduce signals to nucleus after phosphorylation via sh2. Example: sos, which activates ras proteins (a type of small, monomeric g-protein)