RSK is not required for ERK activation.

<p>Immunoblots of RhF transfected with non-targeting siRNA (siCNL) or sRSK1+siRSK2, as indicated. (<b>A</b>) 24 h post-transfection cells were infected with RRV (MOI of 5) and then harvested at 48 h p.i. Cell lysates were probed with the indicated antibodies (10–15% of total lysate was loaded per lane). The quantitative immunoblot shown is representative of three separate experiments. (Of note, the original blot from which these two lanes were derived is shown in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1004066#ppat.1004066.s009" target="_blank">Figure S9</a>.) Graphical representation of the expression of (<b>B</b>) pRSK (pRSK2, T573 antibody); compared to siCNL, pRSK levels in the siRSK condition were statistically different; p = 0.0005 or (<b>C</b>) pERK isoforms treated with siRSK1 plus siRSK2 or siRNA control; compared to siCNL, pERK1 and pERK2 levels in the siRSK condition were statistically different (p = 0.0024 and 0.0014. respectively). (<b>D</b>) Quantitative immunoblot of whole cell lysates from a separate siRSK experiment was probed with antibodies to two structural viral proteins, MCP (top panel) and R45 (middle panel) and normalized to GAPDH (bottom panel) to correct for loading (10–15% of total lysate was loaded per lane). (<b>E</b>) Graphical representation of (D); compared to siCNL, R45, but not MCP, levels in the siRSK condition were statistically different (p = 0.0042 and 0.38, respectively). (<b>F</b>) Viral titers in the supernatants from cells in (A); compared to siCNL, titers from supernatants in the siRSK condition were not statistically different (p = 0.50). For (A) through (F), data represent the mean +/− SEM of 3 separate experiments. P values were determined using Student's t test comparing the experimental and control conditions. Columns lacking asterisks were statistically indistinguishable from corresponding siCNL values.