Proteolysis of human eukaryotic translation initiation factor eIF4GII, but not eIF4GI, coincides with the shutoff of host protein synthesis after poliovirus infection

Eukaryotic initiation factor (eIF) 4GI is a component of the cap-binding protein complex eIF4F, which is required for cap-dependent translation. Infection of cells by poliovirus results in a precipitous decline of host cell protein synthesis, which is preceded by the cleavage of eIF4GI. Cleavage of...

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Main Authors: Gradi, Alessandra, Svitkin, Yuri V., Imataka, Hiroaki, Sonenberg, Nahum
Formato: Artigo
Idioma:en
Publicado em: The National Academy of Sciences 1998
Assuntos:
Biological Sciences
Acesso em linha:https://ncbi.nlm.nih.gov/pmc/articles/PMC21600/
https://ncbi.nlm.nih.gov/pubmed/9736694
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spelling pubmed-216002001-03-09 Proteolysis of human eukaryotic translation initiation factor eIF4GII, but not eIF4GI, coincides with the shutoff of host protein synthesis after poliovirus infection Gradi, Alessandra Svitkin, Yuri V. Imataka, Hiroaki Sonenberg, Nahum Proc Natl Acad Sci U S A Biological Sciences Eukaryotic initiation factor (eIF) 4GI is a component of the cap-binding protein complex eIF4F, which is required for cap-dependent translation. Infection of cells by poliovirus results in a precipitous decline of host cell protein synthesis, which is preceded by the cleavage of eIF4GI. Cleavage of eIF4GI results in the inhibition of cap-dependent translation. Poliovirus translation is not affected by eIF4GI cleavage, however, because poliovirus mRNA is translated by a cap-independent mechanism. Cleavage of eIF4GI alone cannot explain the shutoff of host protein synthesis, because after infection in the presence of inhibitors of virus replication, eIF4GI is cleaved, yet host protein synthesis is only partially inhibited. Here we show that eIF4GII, a recently discovered functional homolog of eIF4GI, is more resistant to poliovirus-mediated cleavage than eIF4GI, and that its proteolysis is concomitant with the shutoff of host cell protein synthesis. Moreover, infection with poliovirus in the presence of inhibitors of virus replication resulted in efficient cleavage of eIF4GI, but only partial proteolysis of eIF4GII. Thus, cleavage of both eIF4GI and eIF4GII appears to be required for the shutoff of host protein synthesis after poliovirus infection. These results explain several earlier reports documenting the lack of correlation between eIF4GI cleavage and inhibition of cellular mRNA translation after poliovirus infection. The National Academy of Sciences 1998-09-15 /pmc/articles/PMC21600/ /pubmed/9736694 Text en Copyright © 1998, The National Academy of Sciences
institution US National Library of Medicine
collection PubMed Central
language en
format Article
topic Biological Sciences
spellingShingle Biological Sciences
Gradi, Alessandra
Svitkin, Yuri V.
Imataka, Hiroaki
Sonenberg, Nahum
Proteolysis of human eukaryotic translation initiation factor eIF4GII, but not eIF4GI, coincides with the shutoff of host protein synthesis after poliovirus infection
description Eukaryotic initiation factor (eIF) 4GI is a component of the cap-binding protein complex eIF4F, which is required for cap-dependent translation. Infection of cells by poliovirus results in a precipitous decline of host cell protein synthesis, which is preceded by the cleavage of eIF4GI. Cleavage of eIF4GI results in the inhibition of cap-dependent translation. Poliovirus translation is not affected by eIF4GI cleavage, however, because poliovirus mRNA is translated by a cap-independent mechanism. Cleavage of eIF4GI alone cannot explain the shutoff of host protein synthesis, because after infection in the presence of inhibitors of virus replication, eIF4GI is cleaved, yet host protein synthesis is only partially inhibited. Here we show that eIF4GII, a recently discovered functional homolog of eIF4GI, is more resistant to poliovirus-mediated cleavage than eIF4GI, and that its proteolysis is concomitant with the shutoff of host cell protein synthesis. Moreover, infection with poliovirus in the presence of inhibitors of virus replication resulted in efficient cleavage of eIF4GI, but only partial proteolysis of eIF4GII. Thus, cleavage of both eIF4GI and eIF4GII appears to be required for the shutoff of host protein synthesis after poliovirus infection. These results explain several earlier reports documenting the lack of correlation between eIF4GI cleavage and inhibition of cellular mRNA translation after poliovirus infection.
author Gradi, Alessandra
Svitkin, Yuri V.
Imataka, Hiroaki
Sonenberg, Nahum
author_facet Gradi, Alessandra
Svitkin, Yuri V.
Imataka, Hiroaki
Sonenberg, Nahum
author_sort Gradi, Alessandra
title Proteolysis of human eukaryotic translation initiation factor eIF4GII, but not eIF4GI, coincides with the shutoff of host protein synthesis after poliovirus infection
title_short Proteolysis of human eukaryotic translation initiation factor eIF4GII, but not eIF4GI, coincides with the shutoff of host protein synthesis after poliovirus infection
title_full Proteolysis of human eukaryotic translation initiation factor eIF4GII, but not eIF4GI, coincides with the shutoff of host protein synthesis after poliovirus infection
title_fullStr Proteolysis of human eukaryotic translation initiation factor eIF4GII, but not eIF4GI, coincides with the shutoff of host protein synthesis after poliovirus infection
title_full_unstemmed Proteolysis of human eukaryotic translation initiation factor eIF4GII, but not eIF4GI, coincides with the shutoff of host protein synthesis after poliovirus infection
title_sort proteolysis of human eukaryotic translation initiation factor eif4gii, but not eif4gi, coincides with the shutoff of host protein synthesis after poliovirus infection
publisher The National Academy of Sciences
publisher_facet The National Academy of Sciences
publishDate 1998
url https://ncbi.nlm.nih.gov/pmc/articles/PMC21600/
https://ncbi.nlm.nih.gov/pubmed/9736694
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