Cholesterol sensing by CD81 is important for hepatitis C virus entry

Palor, M. et al. (2020) Cholesterol sensing by CD81 is important for hepatitis C virus entry. Journal of Biological Chemistry, 295(50), pp. 16931-16948. (doi: 10.1074/jbc.RA120.014761) (PMID:32900848) (PMCID:PMC7863897)

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CD81 plays a central role in a variety of physiological and pathological processes. Recent structural analysis of CD81 indicates that it contains an intramembrane cholesterol-binding pocket and that interaction with cholesterol may regulate a conformational switch in the large extracellular domain of CD81. Therefore, CD81 possesses a potential cholesterol-sensing mechanism; however, its relevance for protein function is thus far unknown. In this study we investigate CD81 cholesterol sensing in the context of its activity as a receptor for hepatitis C virus (HCV). Structure-led mutagenesis of the cholesterol-binding pocket reduced CD81–cholesterol association but had disparate effects on HCV entry, both reducing and enhancing CD81 receptor activity. We reasoned that this could be explained by alterations in the consequences of cholesterol binding. To investigate this further we performed molecular dynamic simulations of CD81 with and without cholesterol; this identified a potential allosteric mechanism by which cholesterol binding regulates the conformation of CD81. To test this, we designed further mutations to force CD81 into either the open (cholesterol-unbound) or closed (cholesterol-bound) conformation. The open mutant of CD81 exhibited reduced HCV receptor activity, whereas the closed mutant enhanced activity. These data are consistent with cholesterol sensing switching CD81 between a receptor active and inactive state. CD81 interactome analysis also suggests that conformational switching may modulate the assembly of CD81–partner protein networks. This work furthers our understanding of the molecular mechanism of CD81 cholesterol sensing, how this relates to HCV entry, and CD81's function as a molecular scaffold; these insights are relevant to CD81's varied roles in both health and disease.

Item Type:Articles
Additional Information:—J. G. is supported by Sir Henry Dale Fellowship 107653/Z/15/Z from the Wellcome Trust and Royal Society. L. S. received Wellcome Trust Ph.D. Studentship 109162/Z/15/Z. G. G. was funded by the Knut and Alice Wallenberg Foundation, Deutsche Forschungsgemeinschaft Projektnummer 158989968–SFB 900 Project C7, and Deutsche Forschungsgemeinschaft Project GE 2145/3-2. This work was also supported by funds from the German Academic Exchange Service (to J. K.); the Master Program Infection Biology, Alemania, Argentina (AMIBA) and the ‘Centro Universitario Argentino-Alemán’–‘Deutsch Argentinisches Hochschulzentrum’ (CUAA-DAHZ) (to M. P. A.); and the Infection Biology International Ph.D. Program of Hannover Biomedical Research School (to R. M.).
Glasgow Author(s) Enlighten ID:Grove, Dr Joe
Creator Roles:
Grove, J.Formal analysis, Supervision, Conceptualization, Visualization, Writing – original draft, Project administration
Authors: Palor, M., Stejskal, L., Mandal, P., Lenman, A., Alberione, M. P., Kirui, J., Moeller, R., Ebner, S., Meissner, F., Gerold, G., Shepherd, A. J., and Grove, J.
College/School:College of Medical Veterinary and Life Sciences > School of Infection & Immunity > Centre for Virus Research
Journal Name:Journal of Biological Chemistry
Publisher:American Society for Biochemistry and Molecular Biology, Inc.
ISSN (Online):1083-351X
Published Online:08 September 2020
Copyright Holders:Copyright © 2020 Palor et al.
First Published:First published in Journal of Biological Chemistry 295(30): 16931-16948
Publisher Policy:Reproduced under a Creative Commons License

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