Inhibition of Avian Influenza A Virus Replication in Human Cells by Host Restriction Factor TUFM Is Correlated with Autophagy.

Avian influenza A viruses generally do not replicate efficiently in human cells, but substitution of glutamic acid (Glu, E) for lysine (Lys, K) at residue 627 of avian influenza virus polymerase basic protein 2 (PB2) can serve to overcome host restriction and facilitate human infectivity. Although PB2 residue 627 is regarded as a species-specific signature of influenza A viruses, host restriction factors associated with PB2E have yet to be fully investigated. We conducted immunoprecipitation, followed by differential proteomic analysis, to identify proteins associating with PB2K (human signature) and PB2E (avian signature) of influenza A/WSN/1933(H1N1) virus, and the results indicated that Tu elongation factor, mitochondrial (TUFM), had a higher binding affinity for PB2E than PB2K in transfected human cells.