Domain one of the high affinity IgE receptor, FcεRI, regulates binding to IgE through its interface with domain two

Abstract

The high affinity receptor for IgE, FcεRI, binds IgE through the second Ig-like domain of the α subunit. The role of the first Ig-like domain is not well understood, but it is required for optimal binding of IgE to FcεRI, either through a minor contact interaction or in a supporting structural capacity. The results reported here demonstrate that domain one of FcεRI plays a major structural role supporting the presentation of the ligand- binding site, by interactions generated within the interdomain interface. Analysis of a series of chimeric receptors and point mutants indicated that specific residues within the A' strand of domain one are crucial to the maintenance of the interdomain interf..