Tyrosine phosphorylation of p120Cbl by engagement of CD43. (A) MO7e cells treated with isotype-matched control IgG or anti-CD43 MoAb (clone DF-T1) followed by goat antimouse IgG or 100 U/mL GM-CSF were incubated for 10 minutes at 37°C. Cell lysates were immunoprecipitated with anti-Cbl Ab or preimmune rabbit serum (lane C). Upper panel: these immunoprecipitates were separated by 7.5% SDS-PAGE and immunoblotted with antiphosphotyrosine MoAb; lower panel: the same membrane was reprobed with anti-Cbl. (B) MO7e cells cross-linked with anti-CD43 MoAb (clone DF-T1) were incubated for the indicated time periods at 37°C. Cell lysates were immunoprecipitated with anti-Cbl Ab and followed by immunoblotting with antiphosphotyrosine MoAb (upper panel) and reprobing with anti-Cbl Ab (lower panel). These are the representative results from three separate experiments.
