title: The regulatory subunits of PI3Kγ control distinct neutrophil responses.
abstract: Neutrophils, which migrate toward inflamed sites and kill pathogens by producing reactive oxygen species (ROS), are important in the defense against bacterial and fungal pathogens, but their inappropriate regulation causes various chronic inflammatory diseases. Phosphoinositide 3-kinase γ (PI3Kγ) functions downstream of proinflammatory G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptors (GPCRs) in neutrophils and is a therapeutic target. In neutrophils, PI3Kγ consists of a p110γ catalytic subunit, which is activated by the guanosine triphosphatase Ras, and either a p84 or p101 regulatory subunit. Loss or inhibition of p110γ or expression of a Ras-insensitive variant p110γ (p110γ(DASAA/DASAA)) impairs PIP3 production, Akt phosphorylation, migration, and ROS formation in response to GPCR activation. The p101 subunit binds to, and mediates PI3Kγ activation by, G protein βγ subunits, and p101(-/-) neutrophils have a similar phenotype to that of p110γ(-/-) neutrophils, except that ROS responses are normal. We found that p84(-/-) neutrophils displayed reduced GPCR-stimulated PIP3 and Akt signaling, which was indistinguishable from that of p101(-/-) neutrophils. However, p84(-/-) neutrophils produced less ROS and exhibited normal migration in response to GPCR stimulation. These data suggest that p84-containing PI3Kγ controls GPCR-dependent ROS production. Thus, the PI3Kγ regulatory subunits enable PI3Kγ to mediate distinct neutrophil responses, which may occur by targeting PIP3 signaling into spatially distinct domains.
authors.affiliation: Signalling Department, Babraham Institute, Babraham Research Campus, Cambridge CB22 4AT, UK.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Deladeriere
authors.affiliation: Signalling Department, Babraham Institute, Babraham Research Campus, Cambridge CB22 4AT, UK.
authors.forename: Laure
authors.initials: L
authors.lastname: Gambardella
authors.affiliation: Signalling Department, Babraham Institute, Babraham Research Campus, Cambridge CB22 4AT, UK.
authors.forename: Dingxin
authors.initials: D
authors.lastname: Pan
authors.affiliation: Signalling Department, Babraham Institute, Babraham Research Campus, Cambridge CB22 4AT, UK.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Anderson
authors.affiliation: Signalling Department, Babraham Institute, Babraham Research Campus, Cambridge CB22 4AT, UK.
authors.forename: Phillip T
authors.initials: PT
authors.lastname: Hawkins
authors.affiliation: Signalling Department, Babraham Institute, Babraham Research Campus, Cambridge CB22 4AT, UK. len.stephens@babraham.ac.uk.
authors.forename: Len R
authors.initials: LR
authors.lastname: Stephens
mesh_terms: D000199:Actins / Q000737:chemistry; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002465:Cell Movement / Q000276:immunology*; D002469:Cell Separation / Q000379:methods; D058544:Class Ib Phosphatidylinositol 3-Kinase / Q000235:genetics / Q000378:metabolism*; D019852:Diacylglycerol Kinase; D005434:Flow Cytometry; D005822:Genetic Vectors / Q000235:genetics; D013058:Mass Spectrometry; D051379:Mice; D018345:Mice, Knockout; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism; D051058:Oncogene Protein v-akt / Q000378:metabolism; D010766:Phosphorylation; D058105:Polymerization; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*
chemical_list: D000199:Actins; D021122:Protein Subunits; D017382:Reactive Oxygen Species; D019852:Diacylglycerol Kinase; D058544:Class Ib Phosphatidylinositol 3-Kinase; C546764:Pik3cg protein, mouse; D051058:Oncogene Protein v-akt; D002118:Calcium