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Biosynthesis of paf‐acether XVII. Regulation by the CoA‐independent transacylase in human neutrophils
Author(s) -
Ninio Ewa,
Breton Michelyne,
Bidault Jocelyne,
Colard Odile
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)81053-b
Subject(s) - chemistry , biosynthesis , liberation , phorbol , biochemistry , platelet activating factor , in vitro , enzyme , endocrinology , biology , protein kinase c
Treatment of intact human polymorphonuclear neutrophils (PMN) with low concentrations of phorbol myristate acetate (PMA, 1–10 ng/ml) induced paf‐acether (pat) and lyso paf formation, arachidonate release, and simultaneous inhibition of CoA‐independent lyso paf : transacylase as assayed in a cell‐free system. Inhibition of [ 3 H]lyso paf reacylation was also observed when it was exogenously added to the PMA‐treated intact PMN. When higher concentrations of PMA (40–100 ng/ml) were used, paf biosynthesis was severely impaired and the level of the CoA‐independent transacylase activity returned to basal level. Since lyso paf appears to be the substrate for PMA‐activated paf formation (remodeling pathway), we showed that [ 14 C]acetate was incorporated into the paf molecule. By contrast, labeling with [ 3 H]choline was not appropriate in this model. The presented results are against the involvement of a de novo route in paf synthesis initiated by PMA and open a new possibility of an important role for the CoA‐independent transacylase in controling the level of lyso paf availability for paf formation.