Fig 1: Phosphorylation of SAPK/JNK-Thr183/Tyr185 coincides with AKT-pSer473 anti-apoptotic signaling and is essential for viral protein accumulation in IAV P/Ch/1/73-infected A549 cells. (a) The mTORC1 and mTORC2 activity was deduced from the phosphorylation status of their corresponding substrates, p70S6K-Thr389 and AKT-S473, in IAV-infected (MOI1) cells. (b) mTORC1 activity was measured at later stage of IAV infection (6 and 8 hpi) at MOI 1, 5, and 10. (c) Western blot analysis of phosphorylated JNK-Thr183/Tyr185, total JNK, and IAV nucleocapsid protein (IAV-NP) in samples isolated from virus-infected (V) A549 cells at MOI5 and mock-treated (M) cells. JNK signaling was consequently activated with accumulation of viral protein at mid-to-late stage of the virus replication cycle. (d) Western blot analysis shows that chemical inhibition of SAPK/JNK signaling with SP600125 [10 µM] resulted in inhibition of virus protein (IAV-M2) accumulation in A549 cells. In the same samples, increase in the LC3B-II/LC3B-I ratio indicates that high viral protein levels are responsible for the SAPK/JNK and autophagy activation. Shown is a representative of four independent virus infection (MOI5) experiments