Temporal Proteomic and Phosphoproteomic Analysis of EV-A71-Infected Human Cells.

Human enterovirus A71 (EV-A71), a member of the Picornaviridae family, is one of the main etiological viruses that lead to hand, foot, and mouth disease (HFMD). We utilized a multiplex tandem mass tag-based quantitative proteomic technique to monitor the alternation of the whole cell proteome and phosphoproteome of human rhabdomyosarcoma cells over the course of EV-A71 infection. We successfully quantified more than 7000 host proteins and 17,000 phosphosites, of which 80 proteins and nearly 1700 phosphosites were significantly regulated upon viral infection. We found that Myc proto-oncogene protein level decreased significantly, benefiting EV-A71 replication. Multiple signaling pathways were regulated in phosphorylation events that converge for protein translation, cell cycle control, and cell survival. Numerous host factors targeted by virus proteins are phosphoproteins. These factors are involved in host translational initiation, unfolded protein response, endoplasmic reticulum stress, and stress granule formation, and their phosphorylation may play key roles in the virus life cycle. Notably, we identified three conserved phosphorylation sites on viral polyproteins that have not been previously reported. Our study provides valuable resources for a systematic understanding of the interaction between the host cells and the EV-A71 at the protein and the post-translational level.