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Activation of human neutrophil phospholipase D by three separable mechanisms
Author(s) -
Reinhold Sandra L.,
Prescott Stephen M.,
Zimmerman Guy A.,
McIntyre Thomas M.
Publication year - 1990
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.4.2.2105252
Subject(s) - separable space , phospholipase d , phospholipase , microbiology and biotechnology , chemistry , biology , mathematics , biochemistry , signal transduction , mathematical analysis , enzyme
Activation of human neutrophils by receptor‐mediated agonists, the Ca 2+ ionophore A23187, or the protein kinase C activator phorbol myristate acetate all stimulated phospholipase D activity. This was demonstrated by the increased formation of phosphatidic acid, and in the presence of ethanol, phosphatidylethanol (PEt) accumulation. EGTA completely inhibited A23187‐induced PEt formation, but only one‐half of the fMLP‐induced PEt accumulation. Staurosporin, an inhibitor of protein kinase C, strongly inhibited PMA‐induced PEt formation, but actually stimulated the formation of PEt in response to fMLP by several‐fold. Thus, increased cytosolic Ca 2+ and activated protein kinase C can each lead to activation of phospholipase D, but neither is required for receptor‐mediated activation of phospholipase D activity. Wortmannin is an irreversible inhibitor of the oxidative burst, but does not inhibit NADPH oxidase or known components of signal transduction. Wortmannin inhibited activation of phospholipase D in response to fMPL. It did not directly inhibit phospholipase D, as the response to A23187 was unaffected. Wortmannin did not inhibit other fMPL‐stimulated events, such as aggregation or adherence. We conclude that inhibition by wortmannin defines a third pathway to activation of phospholipase D. Further, its effect on phospholipase D correlates with its effect on the respiratory burst.—R einhold , S. L.; P rescott , S. M.; Z immerman , G. A.; M c I ntyre , T. M. Activation of human neutrophil phospholipase D by three separable mechanisms. FASEB J. 4: 208‐214; 1990.