Skip to Main content Skip to Navigation
Journal articles

The exchangeable apolipoprotein ApoC-I promotes membrane fusion of hepatitis C virus.

Abstract : Cell entry of hepatitis C virus (HCV) is strikingly linked to lipoproteins and their receptors. Particularly, high density lipoprotein (HDL) enhances infectivity of HCV by involving the lipid-transfer function of the scavenger receptor BI, a receptor for both HDL and HCV. Here, we demonstrate that apoC-I, an exchangeable apolipoprotein that predominantly resides in HDL, specifically enhances HCVcc and HCVpp infectivity and increases the fusion rates between viral and target membranes via a direct interaction with the HCV surface. We identify the hypervariable region 1, located at the N terminus of the HCV E2 glycoprotein, as an essential viral component that modulates apoC-I-mediated enhancement of HCV fusion properties. The affinity of apoC-I for the HCV membrane may predispose it for fusion with a target membrane via alterations of its outer phospholipid layer. Conversely, we found that excess apoC-I provided as lipoprotein-free protein induces the disruption of the HCV membrane and subsequent loss of infectivity. Furthermore, our data indicate that HDL neither interacts nor spontaneously exchanges apoC-I with HCV virions. Because apoC-I is not present in serum as a lipoprotein-free form, our results suggest that HDL-embedded apoC-I could be released from the lipoprotein particle through a fine-tuned mechanism regulated via a triple interplay between hypervariable region 1, HDL, and scavenger receptor BI, resulting in optimal apoC-I recruitment on the viral membrane. These results provide the first description of a host serum factor helping the fusion process of an enveloped virus.Cell entry of hepatitis C virus (HCV) is strikingly linked to lipoproteins and their receptors. Particularly, high density lipoprotein (HDL) enhances infectivity of HCV by involving the lipid-transfer function of the scavenger receptor BI, a receptor for both HDL and HCV. Here, we demonstrate that apoC-I, an exchangeable apolipoprotein that predominantly resides in HDL, specifically enhances HCVcc and HCVpp infectivity and increases the fusion rates between viral and target membranes via a direct interaction with the HCV surface. We identify the hypervariable region 1, located at the N terminus of the HCV E2 glycoprotein, as an essential viral component that modulates apoC-I-mediated enhancement of HCV fusion properties. The affinity of apoC-I for the HCV membrane may predispose it for fusion with a target membrane via alterations of its outer phospholipid layer. Conversely, we found that excess apoC-I provided as lipoprotein-free protein induces the disruption of the HCV membrane and subsequent loss of infectivity. Furthermore, our data indicate that HDL neither interacts nor spontaneously exchanges apoC-I with HCV virions. Because apoC-I is not present in serum as a lipoprotein-free form, our results suggest that HDL-embedded apoC-I could be released from the lipoprotein particle through a fine-tuned mechanism regulated via a triple interplay between hypervariable region 1, HDL, and scavenger receptor BI, resulting in optimal apoC-I recruitment on the viral membrane. These results provide the first description of a host serum factor helping the fusion process of an enveloped virus.
Document type :
Journal articles
Complete list of metadata

https://hal.archives-ouvertes.fr/hal-00315131
Contributor : Gilbert Deleage Connect in order to contact the contributor
Submitted on : Wednesday, August 27, 2008 - 5:04:51 PM
Last modification on : Tuesday, July 20, 2021 - 4:32:02 PM

Identifiers

  • HAL Id : hal-00315131, version 1
  • PUBMED : 17761674

Collections

Citation

M. Dreux, B. Boson, S. Ricard-Blum, J. Molle, D. Lavillette, et al.. The exchangeable apolipoprotein ApoC-I promotes membrane fusion of hepatitis C virus.. Journal of Biological Chemistry, American Society for Biochemistry and Molecular Biology, 2007, xxx, pp.32357-32369. ⟨hal-00315131⟩

Share

Metrics

Record views

63