BIO230H1 Lecture Notes - Lecture 9: Mitogen-Activated Protein Kinase Kinase, Receptor Tyrosine Kinase, Histidine Kinase
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BIO230H1 Full Course Notes
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Document Summary
Enzyme-coupled receptors: enzyme-coupled receptors (leading to protein phosphorylation, proteolysis. 6 main classes of enzyme-coupled receptors: receptor tyrosine kinases, receptor serine/threonine kinases, histidine-kinase-associated receptors, receptor guanylyl cyclases, tyrosine-kinase-associated receptors, receptor-like tyrosine phosphatases. All are transmembrane- can receive signals from outside. Mechanism: signal molecule binds to 2 adjacent tyrosine receptors, dimerization of the 2 receptors, brings the 2 tyrosine receptors together, transautophosphorylation: tyrosine receptors phosphorylate each other (across the dimer, effect of transautophosphorylation increased/more phosphorylation. Ratio of mutant receptors : normal functioning receptors. Increased mutant population decreased signalling: signalling wouldn"t completely disappear- dynamic population- when there are mutants, there are also normal receptor that can still function. Effect: phosphorylated receptor tyrosine kinases recruit proteins to mediate downstream signalling. Sh2 or ptb domains (for binding to phosphotyrosine & neighbouring sequences. Sh2 domains: contain 2 binding sites: phosphotyrosine, amino acid side chain (for specificity) Each ommatidia (cells of drosophila eye) arises from epithelial sheet through sequential differentiation.
