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Updated: Oct 15, 2026

Identifying Caspases and their Motifs that Cleave Proteins During Influenza A Virus Infection
Published on: July 21, 2022
Caspases are not involved in the cleavage of translation initiation factor eIF4GI during picornavirus infection
L O Roberts1, A J Boxall, L J Lewis
1School of Biological Sciences, University of Surrey, Guildford, Surrey GU2 5XH, UK. l.roberts@surrey.ac.uk
Abstract:
Infection of cells by many picornaviruses results in the rapid inhibition of cellular protein synthesis due to cleavage of the translation initiation factor eIF4G. The poliovirus (PV) 2A and foot-and-mouth disease virus (FMDV) L proteases are each sufficient to mediate this cleavage, but the cleavage mechanism may be indirect, involving an unidentified cellular protease(s). eIF4G is also targetted for cleavage by caspase-3 during apoptosis. Here, it is shown that caspase inhibitors do not inhibit the cleavage of eIF4GI during PV or FMDV infection. Similarly, in transient-expression studies, the cleavage of eIF4GI induced by PV 2A or FMDV L was unaffected by these inhibitors. Furthermore, the cleavage of eIF4GI was observed in PV-infected MCF-7 cells lacking caspase-3. These data, and the fact that induction of apoptosis yields different eIF4GI cleavage fragments, indicate that caspases do not have a major role in the cleavage of eIF4GI during PV or FMDV infection.
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