Multi-layered control of Galectin-8 mediated autophagy during adenovirus cell entry through a conserved PPxY motif in the viral capsid

PLoS Pathog. 2017 Feb 13;13(2):e1006217. doi: 10.1371/journal.ppat.1006217. eCollection 2017 Feb.

Abstract

Cells employ active measures to restrict infection by pathogens, even prior to responses from the innate and humoral immune defenses. In this context selective autophagy is activated upon pathogen induced membrane rupture to sequester and deliver membrane fragments and their pathogen contents for lysosomal degradation. Adenoviruses, which breach the endosome upon entry, escape this fate by penetrating into the cytosol prior to autophagosome sequestration of the ruptured endosome. We show that virus induced membrane damage is recognized through Galectin-8 and sequesters the autophagy receptors NDP52 and p62. We further show that a conserved PPxY motif in the viral membrane lytic protein VI is critical for efficient viral evasion of autophagic sequestration after endosomal lysis. Comparing the wildtype with a PPxY-mutant virus we show that depletion of Galectin-8 or suppression of autophagy in ATG5-/- MEFs rescues infectivity of the PPxY-mutant virus while depletion of the autophagy receptors NDP52, p62 has only minor effects. Furthermore we show that wildtype viruses exploit the autophagic machinery for efficient nuclear genome delivery and control autophagosome formation via the cellular ubiquitin ligase Nedd4.2 resulting in reduced antigenic presentation. Our data thus demonstrate that a short PPxY-peptide motif in the adenoviral capsid permits multi-layered viral control of autophagic processes during entry.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae
  • Adenovirus Infections, Human / immunology
  • Adenovirus Infections, Human / metabolism*
  • Amino Acid Motifs
  • Animals
  • Autophagy / physiology*
  • Blotting, Western
  • Capsid Proteins / metabolism*
  • Cell Line
  • Enzyme-Linked Immunosorbent Assay
  • Enzyme-Linked Immunospot Assay
  • Flow Cytometry
  • Fluorescent Antibody Technique
  • Galectins / metabolism*
  • Humans
  • Image Processing, Computer-Assisted
  • Mice
  • Microscopy, Confocal
  • Microscopy, Electron, Transmission
  • Virus Internalization*

Substances

  • Capsid Proteins
  • Galectins
  • LGALS8 protein, human

Grant support

This work was in part supported through Agence national de recherche (ANR grant) (ANR 14 IFEC 0003-04, Infect-ERA; project eDEVILLI, HW), through the Initiative de excellence of the Bordeaux University (IdEX-FAC grant, project BRCAvir, HW) and through a PICS CNRS grant, HW). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.