Common and distinct intracellular signaling pathways in human neutrophils utilized by platelet activating factor and FMLP

J Clin Invest. 1997 Mar 1;99(5):975-86. doi: 10.1172/JCI119263.


Stimulation of human neutrophils with chemoattractants FMLP or platelet activating factor (PAF) results in different but overlapping functional responses. We questioned whether these differences might reflect patterns of intracellular signal transduction. Stimulation with either PAF or FMLP resulted in equivalent phosphorylation and activation of the mitogen-activated protein kinase (MAPk) homologue 38-kD murine MAP kinase homologous to HOG-1 (p38) MAPk. Neither FMLP nor PAF activated c-jun NH2-terminal MAPk (JNKs). Under identical conditions, FMLP but not PAF, resulted in significant p42/44 (ERK) MAPk activation. Both FMLP and PAF activated MAP kinase kinase-3 (MKK3), a known activator of p38 MAPk. Both MAP ERK kinase kinase-1 (MEKK1) and Raf are activated strongly by FMLP, but minimally by PAF. Pertussis toxin blocked FMLP-induced activation of the p42/44 (ERK) MAPk cascade, but not that of p38 MAPk. A specific p38 MAPk inhibitor (SK&F 86002) blocked superoxide anion production in response to FMLP and reduced adhesion and chemotaxis in response to PAF or FMLP. These results demonstrate distinct patterns of intracellular signaling for two chemoattractants and suggest that selective activation of intracellular signaling cascades may underlie different patterns of functional responses.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Calcium-Calmodulin-Dependent Protein Kinases / immunology
  • Calcium-Calmodulin-Dependent Protein Kinases / isolation & purification
  • Calcium-Calmodulin-Dependent Protein Kinases / metabolism
  • Cell Adhesion / drug effects
  • Chemotaxis / drug effects
  • Chromatography, Ion Exchange
  • Electrophoresis, Polyacrylamide Gel
  • Humans
  • Imidazoles / pharmacology
  • MAP Kinase Kinase Kinase 1*
  • Mitogen-Activated Protein Kinase Kinases
  • Mitogen-Activated Protein Kinases*
  • N-Formylmethionine Leucyl-Phenylalanine / pharmacology*
  • Neutrophils / metabolism*
  • Pertussis Toxin
  • Phosphorylation
  • Platelet Activating Factor / pharmacology*
  • Precipitin Tests
  • Protein Kinases / immunology
  • Protein Kinases / metabolism
  • Protein-Serine-Threonine Kinases / immunology
  • Protein-Serine-Threonine Kinases / isolation & purification
  • Protein-Serine-Threonine Kinases / metabolism
  • Protein-Tyrosine Kinases / immunology
  • Protein-Tyrosine Kinases / isolation & purification
  • Protein-Tyrosine Kinases / metabolism
  • Proto-Oncogene Proteins / immunology
  • Proto-Oncogene Proteins / metabolism
  • Proto-Oncogene Proteins c-jun / metabolism
  • Proto-Oncogene Proteins c-raf
  • Recombinant Proteins / pharmacology
  • Saccharomyces cerevisiae Proteins*
  • Signal Transduction*
  • Superoxides / metabolism
  • Thiazoles / pharmacology
  • Time Factors
  • Virulence Factors, Bordetella / pharmacology


  • Imidazoles
  • Platelet Activating Factor
  • Proto-Oncogene Proteins
  • Proto-Oncogene Proteins c-jun
  • Recombinant Proteins
  • Saccharomyces cerevisiae Proteins
  • Thiazoles
  • Virulence Factors, Bordetella
  • Superoxides
  • N-Formylmethionine Leucyl-Phenylalanine
  • 6-(4-fluorophenyl)-2,3-dihydro-5-(4-pyridinyl)imidazo(2,1-b)thiazole
  • Pertussis Toxin
  • Protein Kinases
  • Protein-Tyrosine Kinases
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-raf
  • Calcium-Calmodulin-Dependent Protein Kinases
  • HOG1 protein, S cerevisiae
  • Mitogen-Activated Protein Kinases
  • MAP Kinase Kinase Kinase 1
  • MAP3K1 protein, human
  • Mitogen-Activated Protein Kinase Kinases