Abstract
The molecular mechanisms by which receptors regulate the Ras Binding Domains of the PIP3-generating, class I PI3Ks remain poorly understood, despite their importance in a range of biological settings, including tumorigenesis, activation of neutrophils by pro-inflammatory mediators, chemotaxis of Dictyostelium and cell growth in Drosophila. We provide evidence that G protein-coupled receptors (GPCRs) can stimulate PLCb2/b3 and diacylglycerol- dependent activation of the RasGEF, RasGRP4 in neutrophils. The genetic loss of RasGRP4 phenocopies knock-in of a Ras-insensitive version of PI3Kc in its effects on PI3Kc-dependent PIP3 accumulation, PKB activation, chemokinesis and reactive oxygen species (ROS) formation. These results establish a new mechanism by which GPCRs can stimulate Ras, and the broadly important principle that PLCs can control activation of class I PI3Ks.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cell Line
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Class Ib Phosphatidylinositol 3-Kinase / genetics
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Class Ib Phosphatidylinositol 3-Kinase / metabolism*
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Enzyme Activation / physiology
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Humans
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Mice
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Mice, Knockout
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Neutrophils / enzymology*
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Phospholipase C beta / genetics
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Phospholipase C beta / metabolism*
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Proto-Oncogene Proteins c-akt / genetics
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Proto-Oncogene Proteins c-akt / metabolism*
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Receptors, G-Protein-Coupled / genetics
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Receptors, G-Protein-Coupled / metabolism*
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ras Guanine Nucleotide Exchange Factors / genetics
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ras Guanine Nucleotide Exchange Factors / metabolism*
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ras Proteins / genetics
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ras Proteins / metabolism*
Substances
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RASGRP4 protein, human
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Rasgrp4 protein, mouse
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Receptors, G-Protein-Coupled
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ras Guanine Nucleotide Exchange Factors
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Class Ib Phosphatidylinositol 3-Kinase
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Pik3cg protein, mouse
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Proto-Oncogene Proteins c-akt
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Phospholipase C beta
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ras Proteins