Coordinate synthesis and degradation of the alpha-, beta- and gamma-subunits of the receptor for immunoglobulin E.

The surface receptor for immunoglobulin E (IgE) on rat basophilic leukemia cells and their normal counterparts has been postulated to consist of four polypeptide chains: a 45-kDa alpha-chain which binds IgE, a 33-kDa beta-component and two disulfide-linked, 9-10-kDa gamma-polypeptides. The instability of this complex in mild detergents makes it possible that, in vivo also, the structure may not be stable and that there is an independent assembly or exchange of the chains. We studied this question using surface-labeling and biosynthetic labeling techniques and found that the chains turn over coordinately and do not independently exchange. The results provide further support for the proposal that the alpha beta gamma 2 complex is the unit receptor for IgE.