High affinity immunoglobulin epsilon receptor (FcεRI)

The High affinity immunoglobulin epsilon receptor (FcεRI) is a multi-subunit transmembrane receptor primarily found on the surface of mast cells and basophils, where it serves as the primary initiator of allergic responses [UniProt: P12319]. The receptor complex is composed of an alpha chain, which binds the Fc region of IgE with high affinity, a beta chain that amplifies the signal, and a disulfide-linked gamma chain homodimer containing immunoreceptor tyrosine-based activation motifs (ITAMs) [PubMed: 21651369]. Upon the binding of multivalent allergens to receptor-bound IgE, FcεRI undergoes cross-linking, which triggers an intracellular signaling cascade involving kinases such as Lyn, Syk, and Bruton's tyrosine kinase (BTK) [PubMed: 25907168]. This cascade leads to the rapid release of preformed inflammatory mediators like histamine and the de novo synthesis of leukotrienes and cytokines, resulting in the clinical manifestations of type I hypersensitivity [StatPearls: NBK513315]. Therapeutic targeting of this pathway includes the use of monoclonal antibodies like omalizumab, which sequesters free IgE to prevent its binding to FcεRI, and small-molecule BTK inhibitors that block downstream signaling [DrugBank; PubMed: 33164645].

Other names

FCER1High affinity IgE receptorFc-epsilon RIIgE receptor type I

Inhibition of IgE binding to the alpha subunit of FcεRI; Inhibition of downstream signaling molecules such as Bruton's tyrosine kinase (BTK) to prevent mediator release.