A kinase able to phosphorylate exogenous protein synthesis initiation factor eIF-2 alpha is present in lysates of mengovirus-infected L cells.
Infection of mouse L929 cells by mengovirus resulted in the expression of a kinase activity that selectively phosphorylated the small, 38,000-molecular-weight subunit of eucaryotic initiation factor 2 and histone H2. This kinase activity was independent of host cell RNA synthesis and was located in the postribosomal supernatant (S-100 fraction) early after infection (up to 3 h). At later times after infection (5 h), kinase activity was also associated with the polysome fraction. The kinase present in the S-100 fraction bound strongly to DEAE-cellulose, its peak activity eluting at 0.5 M KCl. Kinase activity was independent of the presence of exogenous double-stranded RNA, and KCl at concentrations greater than 0.1 M inhibited eucaryotic initiation factor 2 phosphorylation. The 67,000-molecular-weight phosphoprotein activated in interferon-treated cells by double-stranded RNA was not detected by standard phosphorylation assays in lysates from mengovirus-infected cells. Labeling of this protein in vivo during 5 h of infection was also not detected. The DEAE-cellulose-purified mengovirus kinase inhibited protein synthesis in reticulocyte lysates, and the inhibition was not reversible by high concentrations of poly(I).poly(C).
D000818:Animals; D003609:Dactinomycin / Q000494:pharmacology; D004769:Enterovirus Infections / Q000235:genetics*; D015852:Eukaryotic Initiation Factor-2; D005786:Gene Expression Regulation; D006657:Histones / Q000378:metabolism; D007739:L Cells; D008574:Mengovirus / Q000235:genetics*; D051379:Mice; D010448:Peptide Initiation Factors / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011070:Poly I-C / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D012156:Reticulocytes / Q000378:metabolism; D012270:Ribosomes / Q000201:enzymology; D013379:Substrate Specificity; D014779:Virus Replication
D015852:Eukaryotic Initiation Factor-2; D006657:Histones; D010448:Peptide Initiation Factors; D010750:Phosphoproteins; D011506:Proteins; D003609:Dactinomycin; D011494:Protein Kinases; D011070:Poly I-C