Unformatted text preview: as much as 1 million fold by this signal transduction cascade since each step involves enzymes which convert many substrates. 4. Example of a receptor tyrosine kinase. Ligand causes dimerization of receptor, activating its kinase activity. It auto-phosphorylates. Phosphorylated cytoplasmic domain binds to other signaling molecules including PI-3 kinase, GAP, and phospholipase C. GAP activates a G-protein. PI-3 kinase phosphorylates inositol phosphate, a membrane phospholipids. PLC hydrolyzes PIP2 into IP3 and DAG. IP3 binds to Ca2+ channel in ER membrane, releasing Ca2+ into cytoplasm. DAG binds to protein kinase C (PKC) along with Ca2+, activating its kinase activity. 5. Signal transduction is a complex web of regulated protein-protein interactions which produce second messengers and activate signal transducing enzymes, ultimately regulating gene expression, metabolism, and the cytoskeleton....
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- Spring '08
- Cell Signaling, kinase activity, Prof. Schlissel