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Reduction by inhibitors of mono(ADP‐ribosyl)transferase of chemotaxis in human neutrophil leucocytes by inhibition of the assembly of filamentous actin
Author(s) -
Allport Jennifer R.,
Donnelly Louise E.,
Hayes Brian P.,
Murray Stephen,
Rendell Nigel B.,
Ray Keith P.,
MacDermot John
Publication year - 1996
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1996.tb15513.x
Subject(s) - chemotaxis , biochemistry , biology , kinase , transferase , protein kinase c , microbiology and biotechnology , receptor , chemistry , enzyme
1 Chemotaxis of human neutrophils is mediated by numerous agents [e.g. N‐formyl‐methionyl‐leucyl‐phenylalanine (FMLP) and platelet activating factor (PAF)] whose receptors are coupled to phospholipase C. However, the subsequent transduction pathway mediating cell movement remains obscure. We now propose involvement of mono(ADP‐ribosyl)transferase activity in receptor‐dependent chemotaxis. 2 Human neutrophils were isolated from whole blood and measurements were made of FMLP or PAF‐dependent actin polymerization and chemotaxis. The activity of cell surface Arg‐specific mono(ADP‐ribosyl)transferase was also measured. Each of these activities was inhibited by vitamin K 3 and similar IC 50 values obtained (4.67 ± 1.46 μ m , 2.0 ± 0.1 μ m and 4.7 ± 0.1 μ m respectively). 3 There were similar close correlations between inhibition of (a) enzyme activity and (b) actin polymerization or chemotaxis by other known inhibitors of mono(ADP‐ribosyl)transferase, namely vitamin K 1 novobiocin, nicotinamide and the efficient pseudosubstrate, diethylamino(benzylidineamino)guanidine (DEA‐BAG). 4 Intracellular Ca 2+ was measured by laser scanning confocal microscopy with two fluorescent dyes (Fluo‐3 and Fura‐Red). Exposure of human neutrophils to FMLP or PAF was followed by transient increases in intracellular Ca 2+ concentration, but the inhibitors of mono(ADP‐ribosyl)transferase listed above had no effect on the magnitude of the response. 5 A panel of selective inhibitors of protein kinase C, tyrosine kinase, protein kinases A and G or phosphatases 1 and 2A showed no consistent inhibition of FMLP‐dependent polymerization of actin. 6 We conclude that eukaryotic Arg‐specific mono(ADP‐ribosyl)transferase activity may be implicated in the transduction pathway mediating chemotaxis of human neutrophils, with involvement in the assembly of actin‐containing cytoskeletal microfilaments.