Nuclear assortment of eIF4E coincides with shut-off of host protein synthesis upon poliovirus infection

Abstract

Eukaryotic initiation factor (eIF) 4E is a subunit of the cap-binding protein complex, eIF4F, which recognizes the cap structure of cellular mRNAs to facilitate translation initiation. eIF4E is assembled into the eIF4F complex via its interaction with eIF4G, an event that is under Akt/mTOR regulation. The eIF4E-eIF4G interaction is regulated by the eIF4E binding partners, eIF4E-binding proteins and eIF4E-transporter. Cleavage of eIF4G occurs upon poliovirus infection and is responsible for the shut-off of host-cell protein synthesis observed early in infection. Here, we document that relocalization of eIF4E to the nucleus occurs concomitantly with cleavage of eIF4G upon poliovirus infection. This event is not dependent upon virus replication, but is dependent on eIF4G cleavage. We postulate that eIF4E nuclear relocalization may contribute to the shut-off of host protein synthesis that is a hallmark of poliovirus infection by perturbing the circular status of actively translating mRNAs.