FcεRI-mediated tyrosine phosphorylation of 3BP2 does not depend on calcium influx from external sources.

Cell lines expressing HA-3BP2 sensitized with anti-DNP IgE were stimulated with 10 ng/mL of antigen DNP-BSA for the indicated times without or with the presence of 0.5 mM EDTA in medium. Cell lysates were immunoprecipitated with anti-HA antibody, and then immunoprecipitates were separated by 10% SDS-PAGE and analyzed by immunoblotting with anti-pTyr and anti-HA antibodies. Similar results were obtained when the other lines were examined.