%0 Journal Article
%T Characterization of a Phospho-Specific Antibody to the Fc¦Å Receptor ¦Ã Chain, Reveals Differences in the Regulation of Syk and Akt Phosphorylation
%A Ryo Suzuki
%A Sarah Leach
%A Barbara Dema
%A Juan Rivera
%J Antibodies
%D 2013
%I MDPI AG
%R 10.3390/antib2020321
%X We previously demonstrated that the Fc receptor ¦Ã-chain Y 58(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 ¦Ã-chain Y 47 (N-terminal tyrosine) in mast cell signaling. We generated a highly sensitive and versatile phospho-specific antibody that recognized the phosphorylated Y 47 in various species. Using this antibody, we found that mutation of the Fc¦ÅRI¦Â Y 219 to phenylalanine caused a loss in the phosphorylation of the ¦Ã-chain Y 47, consistent with the previously described role of Y 219 in Lyn association with Fc¦ÅRI¦Â and subsequent Fc¦ÅRI¦Ã phosphorylation. These conditions also diminished the tyrosine phosphorylation of Syk and LAT1 but, surprisingly, not the phosphorylation of Akt at T 308. Mutation of Y 47 or Y 58 of the ¦Ã-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 Fc¦ÅRI¦Â Y 219 and both Y 47 and Y 58 of the ¦Ã-chain. However, T 308 phosphorylation of Akt is largely independent of Fc¦ÅRI¦Ã Y 47 phosphorylation and of the Lyn-binding site (Y 219) on the Fc¦ÅRI¦Â.
%K phospho-specific antibody
%K mast cell
%K Fc¦ÅRI
%K immunoreceptor tyrosine-based activation motif (ITAM)
%K Akt
%K Syk
%U http://www.mdpi.com/2073-4468/2/2/321