TRAF2 plays a key, nonredundant role in LIGHT-lymphotoxin beta receptor signaling

Mol Cell Biol. 2005 Mar;25(6):2130-7. doi: 10.1128/MCB.25.6.2130-2137.2005.

Abstract

LIGHT is a member of the tumor necrosis factor (TNF) superfamily, and its function is mediated by at least two receptors, including lymphotoxin beta receptor (LTbetaR) and herpes simplex virus entry mediator. However, the molecular mechanism of LIGHT signaling mediated by LTbetaR has not been clearly defined. In this report, we demonstrate that TRAF2 is critical for LIGHT- and LTbetaR-mediated activation of both the transcription factor NF-kappaB and the mitogen-activated protein kinase JNK. In HeLa cells, LIGHT induces NF-kappaB and JNK activation, which can be blocked by the dominant negative mutant of TRAF2. In these cells, LIGHT causes the recruitment of TRAF2, TRAF3, and IkappaB kinase into the LTbetaR complex. Importantly, while both NF-kappaB and JNK are activated by LIGHT in wild-type mouse embryonic fibroblasts, no activation of either of these two pathways is observed in TRAF2 null fibroblasts. However, LIGHT-induced NF-kappaB and JNK activation can be restored by ectopic expression of TRAF2 in TRAF2-/- cells. Interestingly, in contrast to TNF signaling, the activation of both NF-kappaB and JNK by LIGHT was normal in RIP-/- and TRAF5-/- cells. Taken together, our data demonstrate that TRAF2, an important effector molecule of TNF signaling, plays a critical, nonredundant role in LIGHT-LTbetaR signaling.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • HeLa Cells
  • Humans
  • I-kappa B Kinase
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Lymphotoxin beta Receptor
  • Membrane Proteins / metabolism
  • Membrane Proteins / physiology*
  • Mice
  • Mutation / genetics
  • NF-kappa B / metabolism
  • Protein Serine-Threonine Kinases / metabolism
  • Receptors, Tumor Necrosis Factor / metabolism*
  • Signal Transduction / genetics
  • Signal Transduction / physiology*
  • TNF Receptor-Associated Factor 2 / genetics
  • TNF Receptor-Associated Factor 2 / metabolism
  • TNF Receptor-Associated Factor 2 / physiology*
  • TNF Receptor-Associated Factor 3 / metabolism
  • Tumor Necrosis Factor Ligand Superfamily Member 14
  • Tumor Necrosis Factor-alpha / metabolism
  • Tumor Necrosis Factor-alpha / physiology*

Substances

  • LTBR protein, human
  • Ltbr protein, mouse
  • Lymphotoxin beta Receptor
  • Membrane Proteins
  • NF-kappa B
  • Receptors, Tumor Necrosis Factor
  • TNF Receptor-Associated Factor 2
  • TNF Receptor-Associated Factor 3
  • TNFSF14 protein, human
  • Tnfsf14 protein, mouse
  • Tumor Necrosis Factor Ligand Superfamily Member 14
  • Tumor Necrosis Factor-alpha
  • Protein Serine-Threonine Kinases
  • CHUK protein, human
  • Chuk protein, mouse
  • I-kappa B Kinase
  • IKBKB protein, human
  • IKBKE protein, human
  • Ikbkb protein, mouse
  • Ikbke protein, mouse
  • JNK Mitogen-Activated Protein Kinases