N-Formyl peptide receptor subtypes in human neutrophils activate L-plastin phosphorylation through different signal transduction intermediates.
We investigated the coupling of the fMLP (N -formyl-L-methionyl-L-leucyl-L-phenylalanine; 'chemotactic peptide') receptor with phosphorylation of the actin-binding protein L-plastin in neutrophils. Using two-dimensional IEF (isoelectric focusing)/PAGE and MALDI-TOF (matrix-assisted laser desorption ionization-time-of-flight)-MS, L-plastin was identified as a major phosphoprotein in fMLP-stimulated neutrophils whose phosphorylation was dependent on phosphoinositide 3-kinase, PLD (phospholipase D) and PKC (protein kinase C) activity. Two fMLP receptor subtypes were identified in neutrophils, characterized by a distinct sensitivity to fMLP and antagonistic peptides. Both receptor subtypes induced the phosphorylation of L-plastin. L-plastin phosphorylation induced by low-affinity fMLP receptors involves an action of phosphoinositide 3-kinase, PLD and PKC isotypes. In contrast, none of these intermediates are utilized by high-affinity fMLP receptors in the phosphorylation of L-plastin. However, the PKC inhibitor Ro-31-8220 inhibits L-plastin phosphorylation induced by the high-affinity fMLP receptor. Thus, an as yet unknown Ro-31-8220-sensitive kinase regulates L-plastin phosphorylation in response to the high-affinity fMLP receptor. The results suggest a model in which receptor subtypes induce a similar endpoint event through different signal-transduction intermediates. This may be relevant in the context of cell migration in which one receptor subpopulation may become desensitized in a concentration gradient of chemoattractant.
Paclet
Marie-Hélène
MH
Department of Medicine, Centre for Molecular Medicine, The Rayne Institute, University College London, UK. MHPaclet@chu-grenoble.fr
Davis
Clare
C
Kotsonis
Peter
P
Godovac-Zimmermann
Jasminka
J
Segal
Anthony W
AW
Dekker
Lodewijk V
LV
D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D044042:Receptors, Formyl Peptide / Q000145:classification / Q000378:metabolism*; D015398:Signal Transduction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D010750:Phosphoproteins; D044042:Receptors, Formyl Peptide; C026742:plastin; D009240:N-Formylmethionine Leucyl-Phenylalanine; D011493:Protein Kinase C