Proteomic Approach to FcεRI Aggregation-Initiated Signal Transduction Cascade in Human Mast Cells

Abstract

Background: Mast cells (MCs) play a central role in allergic reactions through high-affinity IgE receptor (FcεRI)-mediated responses. Many attempts have been performed to investigate MC functions, though molecular bases of the intracellular signaling cascade through FcεRI, especially in human MCs, remain scant and unexplored. Methods: Human MCs were differentiated from CD34+ cells by culture with stem cell factor, IL-6 and IL-3. The differential phosphorylation profiles of protein tyrosine residues in the resulting MCs with or without FcεRI aggregation were examined by two-dimensional gel electrophoresis. The candidate phosphoproteins of interest were picked, in-gel digested and mass spectrometry fingerprinted. Results: Approximately 40 proteins in MCs were phosphorylated on their tyrosine residues in response to activation and some of them were identified. Particularly IL-31 receptor α, solute carrier family 39, syntaxin 5 and heterogeneous nuclear ribonucleoprotein are newly identified as phosphoproteins that are potentially involved in the MC signaling cascade through FcεRI. Conclusion: Our present phosphoproteome data may provide the clue to understand the molecular mechanisms for the activation of human MCs.