FIG. 2.

Differential protein synthesis and activation of PKR in R3616-infected cancer cell lines inversely correlates with constitutive MEK activation in uninfected cancer cell lines. (A) Cell lines were infected with 10 PFU/cell of R3616. At 11 h after infection, the cells were rinsed, starved of methionine for 1 h, and then incubated in methionine-free medium supplemented with 100 μCi of [³⁵S]methionine per ml for two additional hours. At 14 h after infection, 20 μg of equilibrated protein lysates was electrophoretically separated in denaturing polyacrylamide gels, transferred to a PVDF membrane, and exposed to autoradiography film. (B) Cells were infected with 10 PFU/cell of R3616, and whole-cell lysates harvested at 12 h after infection were resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotted with an antibody that recognizes the autophosphorylated form of PKR on threonine 446. In the lower panel, after overnight serum starvation uninfected total whole-cell lysates were resolved by SDS-PAGE and immunoblotted with an antibody against the total and phosphorylated forms of ERK on threonine 202 and tyrosine 204.