Human cytomegalovirus UL69 protein facilitates translation by associating with the mRNA cap-binding complex and excluding 4EBP1

Proc Natl Acad Sci U S A. 2010 Feb 9;107(6):2640-5. doi: 10.1073/pnas.0914856107. Epub 2010 Jan 22.

Abstract

4EBP1 is phosphorylated by the mTORC1 kinase. When mTORC1 activity is inhibited, hypophosphorylated 4EBP1 binds and sequesters eIF4E, a component of the mRNA cap-binding complex, and blocks translation. As a consequence, mTORC1 activity is needed to maintain active translation. The human cytomegalovirus pUL38 protein preserves mTORC1 activity, keeping most of the E4BP1 in the infected cell in a hyperphosphorylated, inactive state. Here we report that a second viral protein, pUL69, also antagonizes the activity of 4EBP1, but by a separate mechanism. pUL69 interacts directly with eIF4A1, an element of the cap-binding complex, and the poly(A)-binding protein, which binds to the complex. When pUL69 accumulates during infection with wild-type virus, 4EBP1 is excluded from the complex. However, 4EBP1 is present in the cap-binding complex after infection with a pUL69-deficient virus, coincident with reduced accumulation of several late virus-coded proteins. We propose that pUL69 supports translation in human cytomegalovirus-infected cells by excluding hypophosphorylated 4EBP1 from the cap-binding complex.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Cell Line
  • Cytomegalovirus / genetics
  • Cytomegalovirus / metabolism
  • Eukaryotic Initiation Factor-4E / genetics
  • Eukaryotic Initiation Factor-4E / metabolism*
  • Humans
  • Immunoprecipitation
  • Mutation
  • Peptide Chain Initiation, Translational
  • Poly(A)-Binding Protein I / genetics
  • Poly(A)-Binding Protein I / metabolism
  • Poly(A)-Binding Proteins / genetics
  • Poly(A)-Binding Proteins / metabolism
  • Polyribosomes / metabolism
  • Protein Binding
  • Protein Biosynthesis*
  • RNA Caps / metabolism*
  • RNA, Messenger / genetics
  • RNA, Viral / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Two-Hybrid System Techniques

Substances

  • Eukaryotic Initiation Factor-4E
  • Poly(A)-Binding Protein I
  • Poly(A)-Binding Proteins
  • RNA Caps
  • RNA, Messenger
  • RNA, Viral
  • Trans-Activators
  • pUL69 protein, Human herpesvirus 5