Coexpression of PKCδ inhibits Bmx-induced tyrosine phosphorylation of Stat1. Stat1α (4 μg) and Bmx (3 μg) expression vectors were transfected into COS cells together with the PKC vectors (4 μg). Stat1α was immunoprecipitated from cell lysates using anti-HA antibodies. The immunoprecipitates were separated in 7.5% SDS-PAGE, transferred to nitrocellulose membrane, and probed for anti-phosphotyrosine. Shown in the lower panel is an immunoblot from total cell lysates electrophoresed in 7.5% SDS-PAGE probed for Stat1α using anti-HA antibodies.