High-affinity immunoglobulin E receptor (FcεRI)

The high-affinity immunoglobulin E receptor (Fc epsilon RI) is a multimeric, cell surface immune recognition receptor found primarily on mast cells and basophils in humans and mice. It consists of an alpha chain (FcεRIα) that binds IgE, a beta chain (FcεRIβ) that supports receptor assembly and signaling, and a dimer of FcRγ chains that contain immunoreceptor tyrosine-based activation motifs (ITAMs) essential for signal transduction. Upon binding antigen via IgE, FcεRI crosslinks and recruits intracellular kinases, leading to cell activation, degranulation, and inflammatory mediator release that drive allergic responses. In humans, FcεRI also exists in a trimeric form (lacking the beta chain) on antigen-presenting cells, where it mediates IgE-dependent antigen presentation. Dysregulated FcεRI expression and function are strongly linked to a spectrum of allergic and inflammatory diseases, making it a well-validated therapeutic target. Drugs such as omalizumab block interaction with IgE, reducing cell activation and allergic symptoms.

Other names

Fc epsilon RIHigh-affinity IgE receptorIgE receptorFcεRIReceptors, IgE

Inhibition of IgE binding (blocking the IgE-FcεRI interaction inhibits mast cell activation and allergic responses; this is the mechanism of the drugs listed above). Down-regulation of surface FcεRI expression