Tyrosine phosphorylation is involved in the respiratory burst of electropermeabilized human neutrophils at a step before diacylglycerol formation by phospholipase C.
We studied a step where tyrosine phosphorylation is involved in a signaling pathway for the activation of the superoxide (O2-)-generating NADPH oxidase using electropermeabilized human neutrophils. The permeabilized cells produced O2- by the addition of a protein tyrosine phosphatase inhibitor, vanadate, as well as N-formyl-methionyl-leucyl-phenylalanine (fMLP) and protein kinase C (PKC) activators such as phorbol myristate acetate (PMA) and L-alpha-1-oleoyl-2-acetoyl-sn-3-glycerol (OAG). The O2- production by the stimulants was completely inhibited by PKC inhibitors such as calphostin C and staurosporine and was not affected by 1% ethanol, a metabolic modulator of phospholipase D (PLD). Furthermore, the O2- production by vanadate and fMLP, but not by OAG and PMA, was inhibited by both an inhibitor of phospholipase C (PLC), neomycin, and an inhibitor of tyrosine kinase, ST-638. These findings suggest that tyrosine phosphorylation is involved in the activation of the oxidase at a step before diacylglycerol formation by PLC, and that PLD may not be involved in the signaling pathway in permeabilized cells.
Mitsuyama
T
T
Department of Biochemistry, Kyushu University School of Medicine, Fukuoka, Japan.
Takeshige
K
K
Minakami
S
S
D002463:Cell Membrane Permeability; D002934:Cinnamates / Q000494:pharmacology; D004075:Diglycerides / Q000378:metabolism*; D000431:Ethanol / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D009281:Naphthalenes; D009355:Neomycin / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010766:Phosphorylation; D011083:Polycyclic Compounds / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D016897:Respiratory Burst; D013440:Sulfides / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
C011439:1,2-diacylglycerol; D002934:Cinnamates; D004075:Diglycerides; D009281:Naphthalenes; D011083:Polycyclic Compounds; D013440:Sulfides; C060747:ST 638; D000431:Ethanol; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D010738:Type C Phospholipases; D009355:Neomycin; C058819:calphostin C; D010100:Oxygen