Open AccessTreatment of human platelets with trypsin, thrombin, or collagen inhibits the pertussis toxin-induced ADP-ribosylation of a 41-kDa protein.
Author(s) -
Eduardo G. Lapetina,
Bryan R. Reep,
KwenJen Chang
Publication year - 1986
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.83.16.5880
Subject(s) - adp ribosylation , thrombin , trypsin , pertussis toxin , biochemistry , leupeptin , platelet , chemistry , microbiology and biotechnology , protease , g protein , enzyme , biology , nad+ kinase , receptor , immunology
Permeabilization of human platelets with saponin (15-25 micrograms/ml) allows the determination of the ADP-ribosylation of a 41-kDa protein by pertussis toxin. The ADP-ribosylated protein is present in the particulate fraction. ADP-ribosylation of the 41-kDa protein increases for 20 min; it is not affected by indomethacin, prostacyclin, and 1,2-diacylglycerols but is inhibited by 1 mM Ca2+ and phorbol esters. Treatment of platelets with trypsin, thrombin, or collagen before saponin addition precludes subsequent pertussis toxin-induced ADP-ribosylation of the 41-kDa protein. The effect of trypsin or thrombin is blocked by soybean trypsin inhibitor and leupeptin. Trypsin proteolytically cleaves the ADP-ribosylated 41-kDa protein to an ADP-ribosylated fragment slightly smaller than 20 kDa. The results suggest that a modification of a guanine nucleotide-binding regulatory protein is associated with the actions of trypsin, thrombin, and collagen on platelet activation.