title: A chemical biology approach demonstrates G protein βγ subunits are sufficient to mediate directional neutrophil chemotaxis.
abstract: Our laboratory has identified a number of small molecules that bind to G protein βγ subunits (Gβγ) by competing for peptide binding to the Gβγ "hot spot." M119/Gallein were identified as inhibitors of Gβγ subunit signaling. Here we examine the activity of another molecule identified in this screen, 12155, which we show that in contrast to M119/Gallein had no effect on Gβγ-mediated phospholipase C or phosphoinositide 3-kinase (PI3K) γ activation in vitro. Also in direct contrast to M119/Gallein, 12155 caused receptor-independent Ca(2+) release, and activated other downstream targets of Gβγ including extracellular signal regulated kinase (ERK), protein kinase B (Akt) in HL60 cells differentiated to neutrophils. We show that 12155 releases Gβγ in vitro from Gαi1β1γ2 heterotrimers by causing its dissociation from GαGDP without inducing nucleotide exchange in the Gα subunit. We used this novel probe to examine the hypothesis that Gβγ release is sufficient to direct chemotaxis of neutrophils in the absence of receptor or G protein α subunit activation. 12155 directed chemotaxis of HL60 cells and primary neutrophils in a transwell migration assay with responses similar to those seen for the natural chemotactic peptide n-formyl-Met-Leu-Phe. These data indicate that release of free Gβγ is sufficient to drive directional chemotaxis in a G protein-coupled receptor signaling-independent manner.
authors.affiliation: From the Departments of Biochemistry and Biophysics and.
authors.forename: Chinmay R
authors.initials: CR
authors.lastname: Surve
authors.affiliation: Pharmacology and Physiology, University of Rochester, Rochester, New York 14642.
authors.forename: David
authors.initials: D
authors.lastname: Lehmann
authors.affiliation: From the Departments of Biochemistry and Biophysics and Pharmacology and Physiology, University of Rochester, Rochester, New York 14642 alan_smrcka@urmc.rochester.edu.
authors.forename: Alan V
authors.initials: AV
authors.lastname: Smrcka
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology*; D003510:Cyclohexanes / Q000737:chemistry / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000235:genetics / Q000378:metabolism; D044387:GTP-Binding Protein beta Subunits / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D044388:GTP-Binding Protein gamma Subunits / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018922:HL-60 Cells; D006801:Humans; D051379:Mice; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000166:cytology / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D014966:Xanthenes / Q000737:chemistry / Q000494:pharmacology
chemical_list: D003510:Cyclohexanes; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; C509953:M119 compound; D014966:Xanthenes; D009240:N-Formylmethionine Leucyl-Phenylalanine; C007820:gallein; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D002118:Calcium
keywords: Cell Signaling; Chemical Biology; Chemotaxis; G Protein; G Protein-coupled Receptor (GPCR)