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. Author manuscript; available in PMC: 2014 Jan 16.
Published in final edited form as: Cell Host Microbe. 2013 Jan 16;13(1):67–76. doi: 10.1016/j.chom.2012.11.009

Figure 4. p38 Inhibition Blocks CVB3-induced Apoptosis Indirectly Via ERK1/2 Hyperactivation.

Figure 4

(A) CVB3-induced caspase processing is blocked by SB-mediated inhibition of p38.

(B–D) p38 activation via DOX-inducible MKK6-EE does not affect CVB3-induced apoptosis but suppresses ERK1/2 phosphorylation. For (B) and (D), HL1 cells stably expressing doxycycline (DOX)-inducible MKK6-EE were treated with 1 μg/ml DOX for 8 hr and analyzed for the indicated proteins by immunoblotting with tubulin used as a loading control.

(E) SB-mediated inhibition of caspase processing is blocked by co-inhibition of ERK1/2 signaling with PD.

(F) ERK1/2 inhibition with PD does not affect CVB3-induced apoptosis.

For (A), (E), and (F), HL1 cells were pretreated with SB203580 (SB, 20 μM), PD184352 (PD, 2 μM), or SB+PD for one hour, and infected with sham or CVB3 at M.O.I. = 9. For (C), HL1 cells stably expressing DOX-inducible MKK6-EE were infected with CVB3 at M.O.I. = 1.5 and treated with 1 μg/ml DOX at 8 h p.i.. Samples were analyzed for the indicated active caspase-cleavage products at 24 h p.i. by immunoblotting with tubulin or full-length caspases used as a loading control. Densitometry measurements were normalized to sham-infected cells without inhibitor and data are shown as the mean ± s.e.m of four biological replicates. Asterisk indicates p < 0.05 by Welch's one-sided t test. See also Figure S4.