The PDZ-binding motif of severe acute respiratory syndrome coronavirus envelope protein is a determinant of viral pathogenesis

PLoS Pathog. 2014 Aug 14;10(8):e1004320. doi: 10.1371/journal.ppat.1004320. eCollection 2014 Aug.

Abstract

A recombinant severe acute respiratory syndrome coronavirus (SARS-CoV) lacking the envelope (E) protein is attenuated in vivo. Here we report that E protein PDZ-binding motif (PBM), a domain involved in protein-protein interactions, is a major determinant of virulence. Elimination of SARS-CoV E protein PBM by using reverse genetics caused a reduction in the deleterious exacerbation of the immune response triggered during infection with the parental virus and virus attenuation. Cellular protein syntenin was identified to bind the E protein PBM during SARS-CoV infection by using three complementary strategies, yeast two-hybrid, reciprocal coimmunoprecipitation and confocal microscopy assays. Syntenin redistributed from the nucleus to the cell cytoplasm during infection with viruses containing the E protein PBM, activating p38 MAPK and leading to the overexpression of inflammatory cytokines. Silencing of syntenin using siRNAs led to a decrease in p38 MAPK activation in SARS-CoV infected cells, further reinforcing their functional relationship. Active p38 MAPK was reduced in lungs of mice infected with SARS-CoVs lacking E protein PBM as compared with the parental virus, leading to a decreased expression of inflammatory cytokines and to virus attenuation. Interestingly, administration of a p38 MAPK inhibitor led to an increase in mice survival after infection with SARS-CoV, confirming the relevance of this pathway in SARS-CoV virulence. Therefore, the E protein PBM is a virulence domain that activates immunopathology most likely by using syntenin as a mediator of p38 MAPK induced inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Chlorocebus aethiops
  • Disease Models, Animal
  • Female
  • Host-Parasite Interactions / physiology*
  • Immunoprecipitation
  • Mice
  • Mice, Inbred BALB C
  • Microscopy, Confocal
  • Oligonucleotide Array Sequence Analysis
  • PDZ Domains / physiology*
  • Polymerase Chain Reaction
  • SARS Virus / pathogenicity*
  • Severe Acute Respiratory Syndrome / metabolism
  • Severe Acute Respiratory Syndrome / virology*
  • Signal Transduction / physiology
  • Syntenins / metabolism
  • Two-Hybrid System Techniques
  • Vero Cells
  • Viral Envelope Proteins / metabolism*
  • Virulence
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • E protein, SARS coronavirus
  • Sdcbp protein, mouse
  • Syntenins
  • Viral Envelope Proteins
  • p38 Mitogen-Activated Protein Kinases