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  • Title: Positive regulation of c-Jun N-terminal kinase and TNF-alpha production but not histamine release by SHP-1 in RBL-2H3 mast cells.
    Author: Xie ZH, Zhang J, Siraganian RP.
    Journal: J Immunol; 2000 Feb 01; 164(3):1521-8. PubMed ID: 10640770.
    Abstract:
    The SH2-containing protein tyrosine phosphatase1 (SHP-1) is important for signaling from immune receptors. To investigate the role of SHP-1 in mast cells we overexpressed the wild-type and the phosphatase-inactive forms of SHP-1 in rat basophilic leukemia 2H3 (RBL-2H3) mast cell line. The phosphatase-inactive SHP-1 (C453S or D419A) retains its ability to bind tyrosine phosphorylated substrates and thereby competes with the endogenous wild-type enzyme. Overexpression of wild-type SHP-1 decreased the FcepsilonRI aggregation-induced tyrosine phosphorylation of the beta and gamma subunits of the receptor whereas the dominant negative SHP-1 enhanced phosphorylation. There were also similar changes in the tyrosine phosphorylation of Syk. However, receptor-induced histamine release in the cells expressing either wild-type or dominant negative SHP-1 was similar to that in the parental control cells. In contrast, compared with the parental RBL-2H3 cells, FcepsilonRI-induced c-Jun N-terminal kinase phosphorylation and the level of TNF-alpha mRNA was increased in the cells overexpressing wild-type SHP-1 whereas the dominant negative SHP-1 had the opposite effect. The substrate-trapping mutant SHP1/D419A identified pp25 and pp30 as two major potential substrates of SHP-1 in RBL-2H3 cells. Therefore, SHP-1 may play a role in allergy and inflammation by regulating mast cell cytokine production.
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