Unusual roles of host metabolic enzymes and housekeeping proteins in plant virus replication

Viruses have developed the ability to improvise their own replication machineries with host proteins, adapt to different environments, and overcome difficulties encountered during various stages of their infection cycles. The modular nature of protein functional motifs allows for the novel use of ordinary host factors. Recent studies have revealed that positive-sense RNA [(+)RNA] viruses may adapt regular metabolic enzymes and housekeeping proteins of host plants by exploiting unusual functions to accommodate their need for replication, mainly for recruitment and subcellular localization of RNA templates or components of replicase complexes and for controlling switches in different stages of replication. This review compares the newly discovered roles of selected metabolic enzymes and housekeeping proteins in plant (+)RNA virus replication with their original cellular functions and the different consequences when utilized by different viruses.

► The unusual roles of host proteins in plant (+)RNA virus replication are discussed.
► Multi-functionality of host proteins contributes to the non-canonical roles.
► Different viruses may exploit different host proteins for similar function.
► The same host protein may be adapted by different viruses for distinct functions.
► Unusual roles of host proteins mainly involve the membrane-associated VRC assembly.