Abstract
Viral infection constitutes an unwanted intrusion that needs to be eradicated by host cells. On one hand, one of the first protective barriers set up to prevent viral replication, spread or persistence involves the induction of apoptotic cell death that aims to limit the availability of the cellular components for viral amplification. On the other hand, while they completely depend on the host molecular machinery, viruses also need to evade the cellular responses that are meant to destroy them. The existence of numerous antiapoptotic products within the viral kingdom proves that apoptosis constitutes a major threat that should better be bypassed. Among the different strategies developed to deal with apoptosis, one is based on what viruses do best: backfiring the cell on itself. Several unrelated viruses have been described to take advantage of apoptosis induction by expressing proteins targeted by caspases, the key effectors of apoptotic cell death. Caspase cleavage of these proteins results in various consequences, from logical apoptosis inhibition to more surprising enhancement or attenuation of viral replication. The present review aims at discussing the characterization and relevance of this post-translational modification that adds a new complexity in the already intricate host–apoptosis–virus triangle.
Highlights
When a viral infection threatens cells, one of the first measures they take is to induce apoptosis to restrict viral replication and spread.1–3 Dying this way, host cells are likely to generate specific signals aiming at triggering the immune system with innate and/or adaptative responses allowing the eradication of the invader.4,5 On the other hand, viruses have evolved a huge arsenal of strategies meant to either counteract or deal with this destructive process to ensure their survival.6–8 Apoptotic cell death is accompanied by characteristic morphological changes and at a molecular level by the activation of first initiator and effector cysteinyl aspartate proteinases or caspases.9,10 Activated caspases act through a catalytic Cys that hydrolyzes peptide bonds within the substrate, with a stringent specificity for Asp residue at P1 position
Many viruses have developed strategies to inhibit this process through various mechanisms
Human papillomavirus (HPV) induces a DNA damage response that leads to caspase 3-dependent apoptosis
Summary
When a viral infection threatens cells, one of the first measures they take is to induce apoptosis to restrict viral replication and spread.1–3 Dying this way, host cells are likely to generate specific signals aiming at triggering the immune system with innate and/or adaptative responses allowing the eradication of the invader.4,5 On the other hand, viruses have evolved a huge arsenal of strategies meant to either counteract or deal with this destructive process to ensure their survival.6–8 Apoptotic cell death is accompanied by characteristic morphological changes (cellular rounding-up and volume reduction, chromatin condensation, nuclear fragmentation, plasma membrane blebbingy) and at a molecular level by the activation of first initiator and effector cysteinyl aspartate proteinases or caspases.9,10 Activated caspases act through a catalytic Cys that hydrolyzes peptide bonds within the substrate, with a stringent specificity for Asp residue at P1 position (the nature of residues at positions P2, P3 and P4 depending on the caspase). HPV induces a DNA damage response that leads to caspase 3-dependent apoptosis.24 Interestingly, HPV E1, a protein involved in viral DNA replication, is a target for caspases 3 and 7 at a site that is conserved in all genital HPVs and preventing E1 cleavage reduces viral amplification.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
