Antibodies 2013, 2(2), 321-337; doi:10.3390/antib2020321
Article

Characterization of a Phospho-Specific Antibody to the Fcε Receptor γ Chain, Reveals Differences in the Regulation of Syk and Akt Phosphorylation

Laboratory of Molecular Immunogenetics, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Building 10, Room 13C103, Bethesda, MD 20892, USA
* Author to whom correspondence should be addressed.
Received: 10 April 2013; in revised form: 20 April 2013 / Accepted: 3 May 2013 / Published: 13 May 2013
(This article belongs to the Special Issue Cytokine Growth Factor Antibodies in Immunotherapy)
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Abstract: We previously demonstrated that the Fc receptor γ-chain Y58(C-terminal tyrosine) is highly susceptible to dephosphorylation; a mechanism that controls the extent of Syk activation and the downstream signaling in mast cells. Here, we explored the importance of the γ-chain Y47 (N-terminal tyrosine) in mast cell signaling. We generated a highly sensitive and versatile phospho-specific antibody that recognized the phosphorylated Y47 in various species. Using this antibody, we found that mutation of the FcεRIβ Y219 to phenylalanine caused a loss in the phosphorylation of the γ-chain Y47, consistent with the previously described role of Y219 in Lyn association with FcεRIβ and subsequent FcεRIγ phosphorylation. These conditions also diminished the tyrosine phosphorylation of Syk and LAT1 but, surprisingly, not the phosphorylation of Akt at T308. Mutation of Y47 or Y58 of the γ-chain also caused a marked inhibition of Syk and LAT1 phosphorylation, but only the latter mutant showed a reduction in Akt phosphorylation. These findings show that the full phosphorylation of Syk and LAT1 requires the FcεRIβ Y219 and both Y47 and Y58 of the γ-chain. However, T308 phosphorylation of Akt is largely independent of FcεRIγ Y47 phosphorylation and of the Lyn-binding site (Y219) on the FcεRIβ.
Keywords: phospho-specific antibody; mast cell; FcεRI; immunoreceptor tyrosine-based activation motif (ITAM); Akt; Syk

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MDPI and ACS Style

Suzuki, R.; Leach, S.; Dema, B.; Rivera, J. Characterization of a Phospho-Specific Antibody to the Fcε Receptor γ Chain, Reveals Differences in the Regulation of Syk and Akt Phosphorylation. Antibodies 2013, 2, 321-337.

AMA Style

Suzuki R, Leach S, Dema B, Rivera J. Characterization of a Phospho-Specific Antibody to the Fcε Receptor γ Chain, Reveals Differences in the Regulation of Syk and Akt Phosphorylation. Antibodies. 2013; 2(2):321-337.

Chicago/Turabian Style

Suzuki, Ryo; Leach, Sarah; Dema, Barbara; Rivera, Juan. 2013. "Characterization of a Phospho-Specific Antibody to the Fcε Receptor γ Chain, Reveals Differences in the Regulation of Syk and Akt Phosphorylation." Antibodies 2, no. 2: 321-337.

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