TNFAIP8: A New Effector for Galpha(i) Coupling to Reduce Cell Death and Induce Cell Transformation

J Cell Physiol. 2010 Nov;225(3):865-74. doi: 10.1002/jcp.22297.


Galpha(i)-coupled receptors comprise a diverse family of receptors that induce transformation by largely unknown mechanisms. We previously found that the Galpha(i)-coupled dopamine-D2short (D2S) receptor transforms Balb-D2S cells via Gαi3. To identify new Gαi effectors, a yeast two-hybrid screen was done using constitutively active Gαi3-Q204L as bait, and tumor necrosis factor-alpha (TNFα)-induced protein 8 (TNFAIP8, SCC-S2/NDED/GG2-1) was identified. In contrast, TNFAIP8-related TIPE1 and TIPE2 showed a very weak interaction with Gαi3. In yeast mating, in vitro pull-down, co-immunoprecipitation and bioluminescence resonance energy transfer (BRET) assays, TNFAIP8 preferentially interacted with activated Gαi proteins, consistent with direct Gαi-TNFAIP8 coupling. Over-expression or depletion of TNFAIP8 using antisense constructs in Balb-D2S cells did not affect D2S-induced signaling to Gαi-dependent inhibition of cAMP. In contrast, antisense depletion of TNFAIP8 completely inhibited spontaneous and D2S-induced foci formation, consistent with a role for TNFAIP8 in Gαi-dependent transformation. To address possible mechanisms, the effect of D2S signaling via TNFAIP8 on TNFα action was examined. D2S receptor activation inhibited TNFα-induced cell death in Balb-D2S cells, but not in cells depleted of TNFAIP8. However, depletion of TNFAIP8 did not prevent D2S-induced inhibition of TNFα-mediated caspase activation, suggesting that D2S/TNFAIP8-induced protection from TNFα-induced cell death is caspase-independent. The data suggest that Gαi-TNFAIP8-mediated rescue of pre-oncogenic cells enhances progression to oncogenic transformation, providing a selective target to inhibit cellular transformation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Apoptosis Regulatory Proteins / genetics
  • Apoptosis Regulatory Proteins / metabolism*
  • BALB 3T3 Cells
  • Caspases / metabolism
  • Cell Death
  • Cell Transformation, Neoplastic / genetics
  • Cell Transformation, Neoplastic / metabolism*
  • Cell Transformation, Neoplastic / pathology
  • Fluorescence Resonance Energy Transfer
  • GTP-Binding Protein alpha Subunit, Gi2 / metabolism
  • GTP-Binding Protein alpha Subunits, Gi-Go / genetics
  • GTP-Binding Protein alpha Subunits, Gi-Go / metabolism*
  • Humans
  • Immunoprecipitation
  • Mice
  • Molecular Sequence Data
  • NIH 3T3 Cells
  • Oligonucleotides, Antisense / metabolism
  • Protein Binding
  • Protein Interaction Mapping
  • Receptors, Dopamine D2 / genetics
  • Receptors, Dopamine D2 / metabolism
  • Signal Transduction*
  • Transfection
  • Tumor Necrosis Factor-alpha / metabolism
  • Two-Hybrid System Techniques


  • Apoptosis Regulatory Proteins
  • Oligonucleotides, Antisense
  • Receptors, Dopamine D2
  • TNFAIP8 protein, mouse
  • Tumor Necrosis Factor-alpha
  • dopamine D2L receptor
  • Caspases
  • GNAI3 protein, human
  • GTP-Binding Protein alpha Subunit, Gi2
  • GTP-Binding Protein alpha Subunits, Gi-Go
  • Gnai2 protein, mouse
  • Gnai3 protein, mouse