Phosphorylated JNK1/2 and p38 MAPK activate downstream targets c-Jun and ATF-2 signals. (A) PK15 cells were infected with PCV2 strain BJW at an MOI of 1 TCID50. PCV2-infected cell lysates at 24, 48, 72, and 96 h, as well as UV-irradiated PCV2-infected cell lysates at 72 h, were harvested and resolved by SDS-PAGE, transferred to nitrocellulose membranes, and immunoblotted. The protein levels of c-Jun and ATF-2 and their phosphorylated forms, as well as of PCV2 viral capsid protein, were analyzed. (B) PK15 cells were infected in the absence or presence of JNK inhibitor 1 (20 μM) or p38 inhibitor SB202190 (20 μM). Cell lysates at 72 h postinfection were harvested to examine c-Jun and ATF-2 phosphorylation. β-Actin was probed as the loading control. p-, Phosphorylated.