BIO230H1 Lecture Notes - Lecture 21: Receptor Tyrosine Kinase, Histidine Kinase, Protein Kinase
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BIO230H1 Full Course Notes
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Document Summary
There are 6 main classes of enzyme-coupled receptors (only need to know 1,3 and 4: receptor tyrosine kinases, tyrosine-kinase-associated receptors, receptor serine/threonine kinases, histidine-kinases-associated receptors, receptor guanylyl cyclases, receptor-like tyrosine phosphatases. About 60 encoded in the human genome. Some bind secreted proteins and others bind cell surface proteins. Outside of plasma membrane: wide range of domains, all of which have tyrosine kinase domains. Many different receptor effects: varied and essential. E. g. , epidermal growth factor (egf) has egf receptors, stimulates cell survival, growth, proliferation, or differentiation of various cell types. E. g. , insulin has insulin receptor, stimulates carbohydrate utilization and protein synthesis. Signaling molecules induce transautophosphorylation (crossphosphorylation) of receptor tyrosine kinases. Ligand binding dimerizes the receptor: signal molecule. The kinase domains are brought together and phosphorylate each other at the same time: phosphorylate each other on different, specific tyrosines. Phosphorylation of the kinase domains enhances their activity. Phosphorylation of other regions creates docking sites to assemble a signaling complex.
