The ubiquitin-proteasome system is the cellular machinery involved in the conjugation of single or multiple ubiquitin molecules to direct protein trafficking or degradation (reviewed in [28] ). In HCV infection, E6AP ubiquitin ligase was reported to mediate the ubiquitination and degradation of the virus core protein [42] . HCV polymerase has also been shown to interact with a ubiquitin-like protein leading to its degradation [43] . In dengue, ubiquitin-proteasome genes have not been reported to be involved in the dengue virus life cycle although a recent publication has shown that dengue envelope protein interacts with SUMO-1 conjugating enzyme 9 (Ubc9) and that overexpression of Ubc9 reduces virus production in a cell line [44] .