Activation of phospholipase D in normodense human eosinophils.
Normodense human eosinophils have been labeled in 1-0-alkyl-phosphatidylcholine (alkyl-PC) with 32P by incubating isolated cells with alkyl-[32P]lysoPC. Stimulation of these 32P-labeled cells with C5a, A23187 or PMA in the presence of 0.5% ethanol resulted in time- and dose-dependent formation of alkyl-[32P]phosphatidic acid (alkyl-[32P]PA) and alkyl-[32P]phosphatidylethanol (alkyl-[32P]PEt). Because cellular ATP does not contain 32P, alkyl-[32P]PA must have been formed by the hydrolytic action of phospholipase D (PLD) and not by the combined actions of phospholipase C and DG kinase. Regardless of the stimulating agent, alkyl-[32P]PEt formation paralleled that of alkyl-[32P]PA, suggesting that alkyl-PEt was the result of a PLD-catalyzed transphosphatidylation reaction between alkyl-PC and ethanol. These data provide the first definitive proof of receptor- and nonreceptor-mediated activation of PLD in normodense eosinophils derived from human blood.
Minnicozzi
M
M
Department of Allergy and Immunology, Schering-Plough Research, Bloomfield, NJ 07003.
Anthes
J C
JC
Siegel
M I
MI
Billah
M M
MM
Egan
R W
RW
D000001:Calcimycin / Q000494:pharmacology; D015936:Complement C5a / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004804:Eosinophils / Q000187:drug effects / Q000201:enzymology*; D000431:Ethanol / Q000494:pharmacology; D020404:Glycerophospholipids; D006801:Humans; D007700:Kinetics; D008213:Lymphocyte Activation / Q000187:drug effects; D010712:Phosphatidic Acids / Q000378:metabolism; D010739:Phospholipase D / Q000096:biosynthesis*; D010740:Phospholipases / Q000096:biosynthesis*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D020404:Glycerophospholipids; D010712:Phosphatidic Acids; C051521:phosphatidylethanol; D000001:Calcimycin; D000431:Ethanol; D015936:Complement C5a; D010740:Phospholipases; D010739:Phospholipase D; D013755:Tetradecanoylphorbol Acetate