Eukaryotic initiation factor 3 is required for poliovirus 2A protease-induced cleavage of the p220 component of eukaryotic initiation factor 4F.
After cultured cells are infected with poliovirus, cellular mRNA fails to bind to ribosomes, and synthesis of the majority of cellular proteins ceases. The defective step has been localized to the cap-dependent activity of the eukaryotic translation initiation factor 4F. Inactivation of this factor correlates with the cleavage of its largest subunit, p220, into characteristic products observed in infected cells. This cleavage is mediated by the poliovirus protease 2Apro. Previous work suggests that 2Apro does not catalyze the reaction directly, suggesting that one or more cellular proteins is required for the degradation of p220. To identify such a protein, we have developed an assay in which cleavage of a p220 substrate in the presence of poliovirus 2Apro is dependent upon the addition of HeLa cell proteins. By using this assay, we show that another factor, eukaryotic translation initiation factor 3, is required for 2Apro-dependent cleavage of p220.
Wyckoff
E E
EE
Department of Biochemistry and Cellular, University of Utah School of Medicine, Salt Lake City 84132.
Hershey
J W
JW
Ehrenfeld
E
E
D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D039621:Eukaryotic Initiation Factor-3; D039562:Eukaryotic Initiation Factor-4F; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D046911:Macromolecular Substances; D008970:Molecular Weight; D010448:Peptide Initiation Factors / Q000302:isolation & purification / Q000378:metabolism*; D010957:Plasmids; D017955:Poliovirus / Q000201:enzymology* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015183:Restriction Mapping; D013379:Substrate Specificity; D014764:Viral Proteins
D039621:Eukaryotic Initiation Factor-3; D039562:Eukaryotic Initiation Factor-4F; D046911:Macromolecular Substances; D010448:Peptide Initiation Factors; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; C057400:picornain 2A, Picornavirus