金山科研平台，产品价格货期咨询微信：jinshanbio Molecule Information: Fc epsilon RI alpha Long Name: Fc epsilon Receptor I alpha Aliases: FCE1A; FCER1A; FcERI Entrez Gene IDs: 2205 (Human); 14125 (Mouse); 25047 (Rat) Background: Fc epsilon RI alpha The alpha subunit of the high affinity IgE receptor (Fc epsilonRIalpha or FcepsilonRIA) is an IgE-binding type I transmembrane glycoprotein of the multichain immune recognition (MIRR) family. The receptor, FcepsilonRI, is a tetrameric complex of one alpha, one beta and two gamma subunits (alpha beta gamma₂) on mast cells and basophils. An alternate trimeric form (alpha gamma₂) is expressed on human, but not rodent, mast cells, basophils, eosinophils and professional antigen presenting cells. While the gamma subunit is essential for expression of FcepsilonRI alpha on the cell surface and for cell signaling, the beta subunit, when present, increases the halflife of the FcepsilonRI complex on the cell surface. An isoform of the beta subunit, betaT, blocks processing of the alpha subunit and its cell surface expression. Human FcepsilonRI alpha cDNA encodes 257 amino acids (aa) including a 25 aa signal sequence, a 180 aa extracellular domain containing two Ig-like domains that bind IgE and an endoplasmic reticulum retention motif, a 21 aa transmembrane domain with a charged amino acid (Asp219) that contributes to intracellular transport, and a 32 aa cytoplasmic sequence. Human FcepsilonRI alpha shares 50-62% aa sequence identity with mouse, rat, equine, ovine, bovine, porcine and canine FcepsilonRI alpha. Binding of IgE alone increases surface expression of FcepsilonRI, while crosslinking of IgE/FcepsilonRI complexes by IgE ligands (allergens) initiates receptor internalization and signaling. Mast cell and basophil activation by IgE/FcepsilonRI crosslinking causes degranulation, releasing histamine, leukotrienes, prostaglandins, and other mediators of immediate-type and late-phase allergic reactions. Circulating autoantibodies that crosslink FcepsilonRI alpha are often found in patients with chronic urticaria. FcepsilonRI on human antigen presenting cells mediates uptake and processing of allergens for presentation by class II MHC. FcepsilonRI expression on human DC and Langerhans cells is up-regulated during allergic reactions (atopy) and correlates with serum IgE concentration.