The TRAF3-binding site of human molluscipox virus FLIP molecule MC159 is critical for its capacity to inhibit Fas-induced apoptosis

Cell Death Differ. 2006 Sep;13(9):1577-85. doi: 10.1038/sj.cdd.4401847. Epub 2006 Jan 20.

Abstract

Members of the viral Flice/caspase-8 inhibitory protein (v-FLIP) family prevent induction of apoptosis by death receptors through inhibition of the processing and activation of procaspase-8 and -10 at the level of the receptor-associated death-inducing signaling complex (DISC). Here, we have addressed the molecular function of the v-FLIP member MC159 of the human molluscum contagiosum virus. MC159 FLIP powerfully inhibited both caspase-dependent and caspase-independent cell death induced by Fas. The C-terminal region of MC159 bound TNF receptor-associated factor (TRAF)3, was necessary for optimal TRAF2 binding, and mediated the recruitment of both TRAFs into the Fas DISC. TRAF-binding-deficient mutants of MC159 showed impaired inhibition of FasL-induced caspase-8 processing and Fas internalization, and had reduced antiapoptotic activity. Our findings provide evidence that a MC159/TRAF2/TRAF3 complex regulates a new aspect of Fas signaling, and identify MC159 FLIP as a molecule that targets multiple features of Fas-induced cell death.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / physiology*
  • Binding Sites
  • CASP8 and FADD-Like Apoptosis Regulating Protein / metabolism*
  • Caspase 10 / metabolism
  • Caspase 8 / metabolism
  • Cell Line
  • Fas Ligand Protein / pharmacology
  • Fas Ligand Protein / physiology*
  • Humans
  • Jurkat Cells
  • Molluscipoxvirus / metabolism*
  • Necrosis
  • Signal Transduction
  • TNF Receptor-Associated Factor 2 / metabolism
  • TNF Receptor-Associated Factor 3 / metabolism*
  • Viral Proteins / metabolism*

Substances

  • CASP8 and FADD-Like Apoptosis Regulating Protein
  • Fas Ligand Protein
  • TNF Receptor-Associated Factor 2
  • TNF Receptor-Associated Factor 3
  • TRAF3 protein, human
  • Viral Proteins
  • Caspase 10
  • Caspase 8