title: Critical role of the carboxyl terminus of proline-rich tyrosine kinase (Pyk2) in the activation of human neutrophils by tumor necrosis factor: separation of signals for the respiratory burst and degranulation.
abstract: Transduction of Tat-tagged fusion proteins confirmed a hypothesis based on pharmacologic inhibitors (Fuortes, M., M. Melchior, H. Han, G.J. Lyon, and C. Nathan. 1999. J. Clin. Invest. 104:327-335) that proline-rich tyrosine kinase (Pyk2) plays a critical role in the activation of adherent human neutrophils, and allowed an analysis of individual Pyk2 domains not possible with chemical inhibitors. Acting as a dominant negative, the COOH terminus of Pyk2 fused to a Tat peptide (Tat-CT), but not other regions of Pyk2, specifically inhibited the respiratory burst of cells responding to tumor necrosis factor (TNF), Salmonella, or Listeria, while sparing responses induced by phorbol ester. Tat-CT suppressed TNF-triggered cell spreading and the phosphorylation of endogenous Pyk2 and the associated tyrosine kinase Syk without blocking the ability of neutrophils to degranulate and kill bacteria. Thus, separate signals control the respiratory burst and degranulation, and a normal rate of killing of some bacteria can be sustained by granule products in conjunction with a minimal residual respiratory burst. Inhibition of select inflammatory functions without impairment of antibacterial activity may commend the Pyk2 pathway as a potential target for antiinflammatory therapy.
authors.affiliation: Department of Microbiology and Immunology, Graduate Programs in Immunology, Weill Medical College of Cornell University, New York, NY 10021, USA.
authors.forename: Hyunsil
authors.initials: H
authors.lastname: Han
authors.forename: Michele
authors.initials: M
authors.lastname: Fuortes
authors.forename: Carl
authors.initials: C
authors.lastname: Nathan
mesh_terms: D002448:Cell Adhesion; D015550:Cell Degranulation / Q000187:drug effects*; D002455:Cell Division; D005434:Flow Cytometry; D051418:Focal Adhesion Kinase 2; D015696:Gene Products, tat / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008089:Listeria monocytogenes / Q000276:immunology / Q000502:physiology; D009154:Mutation; D018375:Neutrophil Activation / Q000187:drug effects*; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology; D011392:Proline / Q000032:analysis; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016897:Respiratory Burst / Q000187:drug effects*; D012486:Salmonella typhimurium / Q000276:immunology / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D015696:Gene Products, tat; D011993:Recombinant Fusion Proteins; D014409:Tumor Necrosis Factor-alpha; D011392:Proline; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2