GPCR activation of Ras and PI3Kc in neutrophils depends on PLCb2/b3 and the RasGEF RasGRP4.
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.
The Inositide Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge, UK
Sabine
S
Suire
Charlotte
C
Lécureuil
Karen E
KE
Anderson
George
G
Damoulakis
Izabella
I
Niewczas
Keith
K
Davidson
Hervé
H
Guillou
Dingxin
D
Pan
Jonathan Clark
Phillip T Hawkins
Len
L
Stephens
D000818:Animals; D002460:Cell Line; D058544:Class Ib Phosphatidylinositol 3-Kinase / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation / Q000502:physiology; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009504:Neutrophils / Q000201:enzymology*; D054799:Phospholipase C beta / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D020663:ras Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism*
C462507:RASGRP4 protein, human; C477240:Rasgrp4 protein, mouse; D043562:Receptors, G-Protein-Coupled; D020663:ras Guanine Nucleotide Exchange Factors; D058544:Class Ib Phosphatidylinositol 3-Kinase; C546764:Pik3cg protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D054799:Phospholipase C beta; D018631:ras Proteins