MARCH8?Ubiquitinates the Hepatitis C Virus Nonstructural 2 Protein and Mediates Viral Envelopment

摘要

The mechanisms that regulate envelopment of HCVand other viruses that bud intracellularly and/orlack late-domain motifs are largely unknown. Wereported that K63 polyubiquitination of the HCVnonstructural (NS) 2 protein mediates HRS (ESCRT-0component) binding and envelopment. Nevertheless,the ubiquitin signaling that governs NS2 ubiquitinationremained unknown. Here, we map the NS2interactome with the ubiquitin proteasome system(UPS) via mammalian cell-based screens. NS2 interactswith E3 ligases, deubiquitinases, and ligase regulators,some of which are candidate proviral or antiviralfactors. MARCH8, a RING-finger E3 ligase,catalyzes K63-linked NS2 polyubiquitination in vitroand in HCV-infected cells. MARCH8 is required forinfection with HCV, dengue, and Zika viruses andspecifically mediates HCV envelopment. Our datareveal regulation of HCV envelopment via ubiquitinsignaling and both a viral protein substrate and aubiquitin K63-linkage of the understudied MARCH8,with potential implications for cell biology, virology,and host-targeted antiviral design.