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Comparison of Stimulation by Chemotactic Formyl Peptide Analogs Between GTPase Activity in Neutrophil Plasma Membranes and Granule Enzyme Release From Intact Neutrophils
Author(s) -
Kanaho Yasunori,
Kermode John C.,
Becker Elmer L.
Publication year - 1990
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.47.5.420
Subject(s) - degranulation , pertussis toxin , stimulation , biology , gtpase , g protein , chemotaxis , peptide , formyl peptide receptor , n formylmethionine leucyl phenylalanine , biochemistry , receptor , endocrinology
Stimulation by fMet‐Leu‐Phe analogs of GTPase activity in plasma membranes from rabbit neutrophils was compared with the stimulation of degranulation in intact neutrophils. All four formyl peptides examined (fMet‐Leu‐Phe‐Phe, fMet‐Leu‐Phe, fNle‐Leu‐Phe, and fVal‐Leu‐Phe) were full agonists for both responses. Their ED 50 values for the two responses correlated well, although those for GTPase stimulation were uniformly about tenfold greater. The specific antagonist tBoc‐Phe‐Leu‐Phe‐Leu‐Phe competitively inhibited both GTPase activity and degranulation stimulated by fMet‐Leu‐Phe; its K values were similar for the two responses. Pertussis toxin treatment, in contrast, inhibited the maximal stimulation of both responses by fMet‐Leu‐Phe with minimal shift in ED 50 . The inhibitory actions of tBoc‐Phe‐Leu‐Phe‐Leu‐Phe and pertussis toxin on GTPase activity thus paralleled the effects on degranulation. These observations substantiate the hypothesis that a guanine nucleotide‐binding protein that is a pertussis toxin substrate couples the formyl peptide receptors to physiological function in the neutrophil.