Enhanced phosphorylation of ribosomal protein s6 and other cytoplasmic proteins after mengovirus infection of Ehrlich ascites tumor cells.

After mengovirus infection of Ehrlich ascites tumor cells, an increased incorporation of radioactive phosphate into ribosomal protein S6 was detected. As judged from the shape of the radioautography spot and the location of the modified protein on the two-dimensional polyacrylamide gel, it must be concluded that more than one phosphate group was incorporated into ribosomal protein S6. Concomitantly, multiple cytoplasmic proteins, particularly those with high affinity for ribosomes, were phosphorylated. Compared with the controls (mock infection), mengovirus infection induced only a slight additional phosphorylation of the proteins of the ribosome-free supernatant. Employing the radio isotope dilution test with 3', 5'-cyclic AMP-binding protein, no enhancement of the intracellular concentration of 3', 5'-cyclic AMP in response to mengovirus infection could be deomonstrated.