title: Effects of selective protein kinase C inhibitors on the proteolytic down-regulation of L-selectin from chemoattractant-activated neutrophils.
abstract: The signaling factors that direct the rapid shedding of L-selectin from neutrophils upon chemoattractant stimulation are poorly understood. Protein kinase C (PKC) has been implicated, yet previous studies have relied on the use of phorbol esters and nonselective kinase inhibitors. We treated neutrophils with various selective kinase inhibitors to evaluate their effects on N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced L-selectin shedding. We found that three selective inhibitors of PKC, structurally related to staurosporine, largely blocked both fMLP- and phorbol 12-myristate 13-acetate (PMA)-induced L-selectin shedding; however, these inhibitors did not affect fMLP-induced up-regulation of Mac-1 (CD11b/CD18) expression, which has been shown not to involve PKC. Other selective serine, threonine, and tyrosine kinase inhibitors were found not to block fMLP-induced L-selectin shedding. These findings provide more definitive evidence for the role of PKC in chemoattractant-induced L-selectin proteolysis. It is interesting that certain highly selective PKC inhibitors, not structurally related to staurosporine, were found to directly induce L-selectin shedding from neutrophils.
authors.affiliation: Center for Immunology, University of Minnesota, St. Paul 55108, USA.
authors.forename: S R
authors.initials: SR
authors.lastname: Alexander
authors.forename: T K
authors.initials: TK
authors.lastname: Kishimoto
authors.forename: B
authors.initials: B
authors.lastname: Walcheck
mesh_terms: D000098:Acetophenones / Q000037:antagonists & inhibitors / Q000494:pharmacology; D015703:Antigens, CD / Q000378:metabolism; D001578:Benzopyrans / Q000037:antagonists & inhibitors / Q000494:pharmacology; D002478:Cells, Cultured; D002630:Chemotactic Factors / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases; D004151:Dipeptides / Q000494:pharmacology; D015536:Down-Regulation / Q000187:drug effects; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D019041:L-Selectin / Q000737:chemistry / Q000378:metabolism*; D008666:Metalloendopeptidases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D009281:Naphthalenes / Q000037:antagonists & inhibitors / Q000494:pharmacology; D018375:Neutrophil Activation; D009504:Neutrophils / Q000187:drug effects / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000037:antagonists & inhibitors / Q000494:pharmacology
chemical_list: D000098:Acetophenones; D015703:Antigens, CD; D001578:Benzopyrans; D002630:Chemotactic Factors; D017868:Cyclic AMP-Dependent Protein Kinases; D017869:Cyclic GMP-Dependent Protein Kinases; D004151:Dipeptides; D006877:Hydroxamic Acids; D019041:L-Selectin; D008666:Metalloendopeptidases; D009240:N-Formylmethionine Leucyl-Phenylalanine; D009281:Naphthalenes; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate; C099147:KD-IX 73-4; C085746:rottlerin; C058819:calphostin C