Induction of Stat3 tyrosine phosphorylation in insect cells. Sf9 cells were infected with Stat3 baculovirus alone or together with Bmx or Jak2 viruses or left uninfected. The cells were lysed 72 hours following infection and the lysates were immunoprecipitated using anti-Stat3 antibodies (A), anti-HA antibodies (Bmx) (B), or anti-Jak2 antibodies (C). The immunoprecipitates were electrophoresed in 7.5% SDS-PAGE, followed by Western immunoblotting using anti-phosphotyrosine antibodies, anti-Stat3 antibodies, anti-HA antibodies, or anti-Jak2 antibodies, as indicated. The anti-phosphotyrosine blot of Stat3-immunoprecipitate from Jak2 coinfected cells (A) is a longer exposure, as we repeatedly found weaker Stat3 tyrosine phosphorylation in Jak2 coinfections than in Bmx coinfections.