Abstract
Hepatitis C virus (HCV) infection induces intracellular membrane rearrangements, thus forming a membranous web (MW) in which HCV replication and assembly occur. The HCV-induced MW is primarily composed of double membrane vesicles (DMVs) transfused by multi-membrane vesicles. The autophagy machinery has been proposed to participate in the formation of such vesicles. However, no clear evidence has been found linking autophagy to the formation of these DMVs. In this study, we evaluated the role of the autophagy elongation complex (ATG5-12/16L1) in HCV replication and MW formation. Using a dominant negative form of ATG12 and an siRNA approach, we demonstrated that the ATG5-12 conjugate, but not LC3-II formation, is crucial for efficient viral replication. Furthermore, purification of HCV MW revealed the presence of ATG5-12 and ATG16L1 along with HCV nonstructural proteins. Interestingly, LC3 was not recruited along with the elongation complex to the site of viral replication. Finally, inhibition of the elongation complex, but not LC3, greatly impaired the formation of the wild-type MW phenotype. To our knowledge, this study provides the first evidence of the involvement of autophagy proteins in the formation of wild-type MWs.
Highlights
Hepatitis C virus (HCV) infection is a leading cause of liver diseases, including cirrhosis and hepatocellular carcinoma
We demonstrated the requirement of the ATG5-12/16L1 complex for the completion of the HCV lifecycle
The involvement of the autophagy elongation complex in the HCV replication step was investigated by using Small interfering RNA (siRNA) targeting of ATG7, ATG12 or LC3
Summary
Hepatitis C virus (HCV) infection is a leading cause of liver diseases, including cirrhosis and hepatocellular carcinoma. The expression of HCV proteins results in the induction of a major rearrangement of host cell membranes, leading to the formation of a complex membranous compartment termed the membranous web (MW), which favors viral RNA replication and assembly[3,4]. This massive remodeling of the host cell membrane network is associated with all positive-strand RNA viruses and is typically characterized by the generation of either convoluted membranes or double membrane vesicles (DMVs)[5,6,7,8]. Knock-down of one component of the elongation complex, ATG12, led to an aberrant MW phenotype, suggesting a novel role of autophagy proteins in the formation of the MW
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