mRNA decapping enzyme 1a (Dcp1a)-induced translational arrest through protein kinase R (PKR) activation requires the N-terminal enabled vasodilator-stimulated protein homology 1 (EVH1) domain

J Biol Chem. 2014 Feb 14;289(7):3936-49. doi: 10.1074/jbc.M113.518191. Epub 2013 Dec 31.

Abstract

We have shown previously that poliovirus infection disrupts cytoplasmic P-bodies in infected mammalian cells. During the infectious cycle, poliovirus causes the directed cleavage of Dcp1a and Pan3, coincident with the dispersion of P-bodies. We now show that expression of Dcp1a prior to infection, surprisingly, restricts poliovirus infection. This inhibition of infection was independent of P-body formation because expression of GFP-Dcp1a mutants that cannot enter P-bodies restricted poliovirus infection similar to wild-type GFP-Dcp1a. Expression of wild-type or mutant GFP-Dcp1a induced phosphorylation of eIF2α through the eIF2α kinase protein kinase R (PKR). Activation of PKR required the amino-terminal EVH1 domain of Dcp1a. This PKR-induced translational inhibition appears to be specific to Dcp1a because the expression of other P-body components, Pan2, Pan3, Ccr4, or Caf1, did not result in the inhibition of poliovirus gene expression or induce eIF2α phosphorylation. The translation blockade induced by Dcp1a expression suggests novel signaling linking RNA degradation/decapping and regulation of translation.

Keywords: MRNA Decay; P-body; Poliovirus; Positive-strand RNA Viruses; Protein Kinase R (PKR); Translation Regulation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Endoribonucleases / genetics
  • Endoribonucleases / metabolism*
  • Enzyme Activation / genetics
  • Eukaryotic Initiation Factor-2 / genetics
  • Eukaryotic Initiation Factor-2 / metabolism
  • Mice
  • Mice, Knockout
  • Mutation
  • Phosphorylation / genetics
  • Poliomyelitis / genetics
  • Poliomyelitis / metabolism
  • Poliomyelitis / pathology
  • Poliovirus / genetics
  • Poliovirus / metabolism
  • Protein Biosynthesis / physiology*
  • Protein Structure, Tertiary
  • Proteins / genetics
  • Proteins / metabolism
  • RNA Stability / physiology*
  • Receptors, CCR4 / genetics
  • Receptors, CCR4 / metabolism
  • Ribonucleases
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • eIF-2 Kinase / genetics
  • eIF-2 Kinase / metabolism*

Substances

  • Ccr4 protein, mouse
  • Eukaryotic Initiation Factor-2
  • Proteins
  • Receptors, CCR4
  • Trans-Activators
  • eIF-2 Kinase
  • Cnot7 protein, mouse
  • Endoribonucleases
  • Ribonucleases
  • smad4-interacting protein SMIF, mouse