Gi-mediated activation of the Syk kinase by the receptor mimetic basic secretagogues of mast cells: Role in mediating arachidonic acid/metabolites release

I. Shefler, R. Sagi-Eisenberg

Research output: Contribution to journalArticlepeer-review

Abstract

Syk kinase is essential for FcεRI-mediated signaling and release of inflammatory mediators from mast cells. We now show that activation of rat peritoneal mast cells by the nonimmunological, Gi-mediated pathway also results in the activation of Syk. We show that compound 48/80 (c48/80), a receptor analogue that activates directly G proteins, activates Syk in a pertussis toxin-sensitive fashion. We further show that Syk activation by c48/80 is blocked by the protein kinase C inhibitor GF109203X, by the phosphatidylinositol 3-kinase inhibitors, wortmannin and LY294002, by EGTA, and by the selective src-like kinase inhibitor PP1. These results suggest that in the nonimmunological, Gi-mediated pathway, Syk is located downstream from phospholipase C and phosphatidylinositol 3-kinase. However, in common with the FcεRI-mediated pathway, activation of Syk by c48/80 is dependent on a src-like protein tyrosine kinase. Finally, we show that in the nonimmunological pathway, Syk plays a central role in the release of arachidonic acid/eicosanoid metabolites, but not in the release of prestored mediators such as histamine.

Original languageEnglish
Pages (from-to)475-481
Number of pages7
JournalJournal of Immunology
Volume167
Issue number1
DOIs
StatePublished - 1 Jul 2001

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