BIOL 2021 Lecture Notes - Lecture 13: Lipid Signaling, Sh2 Domain, Phosphatidylinositol
13 May 2018
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• Docking of enzymes (852-853)
• Fig 15-44 docking on phosphotyrosines
o Ras activated by adaptor proteins that dock on RTK.
o A whole menagerie of intracellular signaling proteins can bind to the
phosphotyrosines on activated RTKs. Some of the docked proteins are
enzymes, such as phospholipase C-γ (PLCγ), which activate the inositol
phospholipid signaling pathway discussed earlier in connection with
GPCRs. Through this pathway, RTKs can increase cytosolic Ca2+ levels
and activate PKC. Another enzyme that docks on these receptors is the
cytoplasmic tyrosine kinase Src, which phosphorylates other signaling
proteins on tyrosines. Yet another is phosphoinositide 3-kinase (PI 3-
kinase), which phosphorylates lipids rather than proteins.
o Examples of enzymes that dock on phosphotyrosines:
o 1) phospholipase C-gamma (PLC gamma). Then the whole pathway is
going to be the same.
• Fig 15-29 phospholipase C
o Increases Ca2+ and DAG and activates PKC.
o 2) SRC = another tyrosine kinase, phosphorylates other signalling
proteins.
• PI 3-kinases (859-861)
o 3) phosphoinositide 3-kinase (PI 3-kinase). Phosphorylates some lipids.
o Wikipedia: Phosphotyrosine (P.Tyr) residues on activated RTKs are
recognized by a phosphodependent-binding domain, the SH2 domain.
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Document Summary
Docking of enzymes (852-853, fig 15-44 docking on phosphotyrosines, ras activated by adaptor proteins that dock on rtk, a whole menagerie of intracellular signaling proteins can bind to the phosphotyrosines on activated rtks. Some of the docked proteins are enzymes, such as phospholipase c- (plc ), which activate the inositol phospholipid signaling pathway discussed earlier in connection with. Through this pathway, rtks can increase cytosolic ca2+ levels and activate pkc. Another enzyme that docks on these receptors is the cytoplasmic tyrosine kinase src, which phosphorylates other signaling proteins on tyrosines. Yet another is phosphoinositide 3-kinase (pi 3- kinase), which phosphorylates lipids rather than proteins: examples of enzymes that dock on phosphotyrosines, 1) phospholipase c-gamma (plc gamma). Then the whole pathway is going to be the same: fig 15-29 phospholipase c. Increases ca2+ and dag and activates pkc: 2) src = another tyrosine kinase, phosphorylates other signalling proteins, pi 3-kinases (859-861, 3) phosphoinositide 3-kinase (pi 3-kinase).
