Fc epsilon RI: Proteins and Enzymes

The allergic reaction is mediated through the IgE high affinity receptor (FceRI). When a multivalent antigen is presented, a redistribution of the monomeric IgE FceRI receptor complexes cause the degranulation of mast cells and basophils, resulting in the subsequent release of factors responsible for the allergic reaction. The FceRI receptor is a tetrameric complex, consisting of a a-chain, b-chain and a dimeric g-chain. While the a-chain is primarily involved with the binding of IgE, the signal is transferred through the g subunit, which contains the immunoreceptor tyrosine activation motifs (ITAM) critical for initiating receptor mediated signal transduction through the Syk and Lyn tyrosine kinases. The FceRI receptor is able to engage and disengage the IgE, providing a versatile model for studying the function of kinase coupled receptors.