Purified receptor-immunoglobulin E (IgE) complexes incubated with [γ-32P]-ATP incorporated phosphorus into tryosines on the β and γ chains of the receptor. The activity had the typical characteristics of a tyrosine kinase. Immunoprecipitation of the complexes with anti-IgE left the activity in the supernatant, demonstrating that the receptor itself was not the kinase. The receptor was also phosphorylated when membranes or intact cells were incubated with radioactive ATP or phosphate, respectively, but in each case the subunits or amino acid residues that were modified were distinctive.
ASJC Scopus subject areas
- Molecular Biology