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Updated: Aug 8, 2026

Static Adhesion Assay for the Study of Integrin Activation in T Lymphocytes
Published on: June 13, 2014
Negative regulation of Fc epsilonRI-mediated signaling and mast cell function by the adaptor protein LAX
Minghua Zhu1, Inmoo Rhee, Yan Liu
1Department of Immunology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Abstract:
LAX is a transmembrane adaptor protein that is expressed in both T and B cells. Upon stimulation via the antigen receptors, it is tyrosine-phosphorylated and binds Grb2 and the p85 subunit of phosphatidylinositol 3-kinase. Disruption of the Lax gene causes hyperresponsiveness in T and B lymphocytes. Here, we showed that LAX was also expressed in mast cells. Upon engagement of the Fc epsilonRI, LAX was also phosphorylated and interacted with Grb2 and p85. LAX-deficient mast cells were hyperresponsive to stimulation via the Fc epsilonRI, as evidenced by enhanced degranulation, p38 MAPK, Akt, and phosphatidylinositol 3-kinase activation. This hyperresponsiveness was likely a consequence of reduced LAB expression after sensitization of mast cells with anti-dinitrophenyl IgE. In addition, Fc epsilonRI-mediated cytokine production and cell survival were also enhanced. These data suggested that LAX negatively regulates mast cell function.
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