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Involvement of protein phosphatase 2A in PKC‐independent pathway of neutrophil superoxide generation by fMLP
Author(s) -
Okuyama Masaki,
Sakon Masato,
Kambayashi Junichi,
Kawasaki Tomio,
Monden Morito
Publication year - 1996
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19960201)60:2<279::aid-jcb12>3.0.co;2-i
Subject(s) - okadaic acid , superoxide , phosphatase , phosphorylation , nadph oxidase , protein kinase c , chemistry , serine , threonine , biochemistry , protein phosphorylation , microbiology and biotechnology , intracellular , reactive oxygen species , protein kinase a , biology , enzyme
We examined the effects of okadaic acid, a protein phosphatase 1 and 2A inhibitor, on superoxide generation in human neutrophils. Superoxide generation induced by fMLP was inhibited by low‐dose okadaic acid (10–100 nM), but it had no effect on superoxide synthesis by PMA, and the fMLP‐induced rise of the intracellular Ca 2+ concentration was not affected by low‐dose okadaic acid. These findings suggested that the inhibitory mechanism of okadaic acid might involve PKC‐independent and Ca 2+ ‐independent pathways in fMLP induced NADPH oxidase activation. Both fMLP‐stimulated phosphorylation of serine residues in p47phox and its translocation to the plasma membrane were suppressed by low‐dose okadaic acid. On the other hand, PMA‐induced phosphorylation and translocation of p47phox were not affected by such a low dose of okadaic acid. These findings suggested that fMLP induced phosphorylation of serine residues in p47phox was regulated by protein phosphatase 2A, and its phosphorylation was necessary for translocation and superoxide generation in fMLP‐activated human neutrophils. © 1996 Wiley‐Liss, Inc.