High-affinity immunoglobulin E receptor (FcεRI) complex (FcεRI)

The High-affinity immunoglobulin E receptor (FcεRI) complex is a multi-subunit protein assembly found on the surface of mast cells, basophils, and dendritic cells that plays a central role in the allergic immune response [PubMed: 10359118]. On mast cells and basophils, the complex typically consists of an alpha chain, a beta chain, and two disulfide-linked gamma chains, whereas on dendritic cells, it exists in a trimeric alpha-gamma-2 form [UniProt: P12319]. The alpha subunit is responsible for binding the Fc region of IgE with high affinity; when allergens cross-link these IgE-bound receptors, it triggers the release of inflammatory mediators like histamine and leukotrienes [StatPearls: NBK538261]. This signaling cascade is mediated by intracellular kinases such as Spleen tyrosine kinase (SYK) and Bruton's tyrosine kinase (BTK) [PubMed: 24011515]. Therapeutic interventions like Omalizumab target the IgE molecule to prevent the formation of the complex, thereby reducing receptor density and cellular reactivity in conditions such as asthma and chronic urticaria [DrugBank: DB00043]. Additionally, small molecule inhibitors targeting the downstream signaling components of the complex are being developed to treat various IgE-mediated disorders.

Other names

Fc epsilon RIFCER1High-affinity IgE receptorIgE-FcεRI complexIgE–FcεRI complex on mast cells, basophils, and dendritic cells

Monoclonal antibodies sequester free IgE to prevent its binding to the receptor, while small molecules inhibit downstream signaling kinases like BTK and SYK activated by the complex.