The germinal center kinase TNIK is required for canonical NF-κB and JNK signaling in B-cells by the EBV oncoprotein LMP1 and the CD40 receptor

PLoS Biol. 2012;10(8):e1001376. doi: 10.1371/journal.pbio.1001376. Epub 2012 Aug 14.

Abstract

The tumor necrosis factor-receptor-associated factor 2 (TRAF2)- and Nck-interacting kinase (TNIK) is a ubiquitously expressed member of the germinal center kinase family. The TNIK functions in hematopoietic cells and the role of TNIK-TRAF interaction remain largely unknown. By functional proteomics we identified TNIK as interaction partner of the latent membrane protein 1 (LMP1) signalosome in primary human B-cells infected with the Epstein-Barr tumor virus (EBV). RNAi-mediated knockdown proved a critical role for TNIK in canonical NF-κB and c-Jun N-terminal kinase (JNK) activation by the major EBV oncoprotein LMP1 and its cellular counterpart, the B-cell co-stimulatory receptor CD40. Accordingly, TNIK is mandatory for proliferation and survival of EBV-transformed B-cells. TNIK forms an activation-induced complex with the critical signaling mediators TRAF6, TAK1/TAB2, and IKKβ, and mediates signalosome formation at LMP1. TNIK directly binds TRAF6, which bridges TNIK's interaction with the C-terminus of LMP1. Separate TNIK domains are involved in NF-κB and JNK signaling, the N-terminal TNIK kinase domain being essential for IKKβ/NF-κB and the C-terminus for JNK activation. We therefore suggest that TNIK orchestrates the bifurcation of both pathways at the level of the TRAF6-TAK1/TAB2-IKK complex. Our data establish TNIK as a novel key player in TRAF6-dependent JNK and NF-κB signaling and a transducer of activating and transforming signals in human B-cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • B-Lymphocytes / metabolism*
  • B-Lymphocytes / virology
  • CD40 Antigens / genetics
  • CD40 Antigens / metabolism*
  • Cell Proliferation
  • Cell Transformation, Viral
  • Germinal Center Kinases
  • HEK293 Cells
  • Herpesvirus 4, Human / genetics
  • Herpesvirus 4, Human / metabolism
  • Herpesvirus 4, Human / pathogenicity
  • Humans
  • MAP Kinase Signaling System*
  • NF-kappa B / genetics
  • NF-kappa B / metabolism
  • Protein Binding
  • Protein Interaction Mapping / methods
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • Proteomics / methods
  • RNA Interference
  • Viral Matrix Proteins / genetics
  • Viral Matrix Proteins / metabolism*

Substances

  • CD40 Antigens
  • EBV-associated membrane antigen, Epstein-Barr virus
  • Germinal Center Kinases
  • NF-kappa B
  • Viral Matrix Proteins
  • Protein Serine-Threonine Kinases
  • TNIK protein, human

Grants and funding

This work was supported by grants of the Deutsche Forschungsgemeinschaft (SFB 455 and SFB 684) and the Helmholtz Association to AK, and by institutional grants. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.