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IgA Fc receptor (CD89) activation enables coupling to syk and Btk tyrosine kinase pathways: differential signaling after IFN‐γ or phorbol ester stimulation
Author(s) -
Launay Pierre,
Lehuen Agnés,
Kawakami Toshiaki,
Blank Ulrich,
Monteiro Renato C.
Publication year - 1998
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.63.5.636
Subject(s) - syk , bruton's tyrosine kinase , biology , tyrosine kinase , microbiology and biotechnology , signal transduction , stimulation , tropomyosin receptor kinase c , ror1 , receptor tyrosine kinase , receptor , cancer research , platelet derived growth factor receptor , biochemistry , endocrinology , growth factor
IgA Fc receptors (FcαR) can mediate a variety of inflammatory responses. It has been demonstrated that the FcRγ subunit is critical in mediating signaling through FcαR. We show that aggregation of FcαR on U937 cells and blood neutrophils results in tyrosine phosphorylation of several intracellular proteins, including the FcR γ subunit, p72 syk , and Bruton tyrosine kinase (Btk). Syk was found to be associated with FcαR and its phosphorylation was increased in phorbol myristate acetate (PMA)‐ and interferon‐γ (IFN‐γ)‐treated U937 cells. In contrast, phosphorylation of Btk was only detected after cell treatment with PMA but not IFN‐γ. These data indicate that signaling through FcαR γ2 involves at least two subfamilies of tyrosine kinases, syk and Btk. Our results also suggest that activation of tyrosine kinase pathways through FcαR depends on the activation state of the cell. This may be an important regulatory mechanism in IgA‐mediated responses at inflammatory sites. J. Leukoc. Biol . 63: 636–642; 1998.