TRAF2 and RIPK1 redundantly mediate classical NFκB signaling by TNFR1 and CD95-type death receptors

  • Cell Death Dis. 2025 Jan 21;16(1):35. doi: 10.1038/s41419-024-07325-x.
Jennifer Wagner  1 ,  David Vredevoogd  2 ,  Xin Yu  3 ,  Dong Lu  3 ,  Daniel S Peeper  2 ,  Heike M Hermanns  4 ,  Jin Wang  3  5  6 ,  Harald Wajant  7 ,  Daniela Siegmund  1
Affiliations
  • 1. Division of Molecular Internal Medicine, Department of Internal Medicine II, University Hospital Würzburg, Auvera Haus Grombühlstraße 12, 97080, Würzburg, Germany.
  • 2. Division of Molecular Oncology and Immunology, Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, the Netherlands.
  • 3. The Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, 77030, USA.
  • 4. Division of Hepatology, Department of Internal Medicine II, University Hospital Würzburg, Auvera Haus Grombühlstraße 12, 97080, Würzburg, Germany.
  • 5. Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA.
  • 6. Center for NextGen Therapeutics, Baylor College of Medicine, Houston, TX, 77030, USA.
  • 7. Division of Molecular Internal Medicine, Department of Internal Medicine II, University Hospital Würzburg, Auvera Haus Grombühlstraße 12, 97080, Würzburg, Germany. [email protected].
PMID: 39837830 DOI: 10.1038/s41419-024-07325-x
Abstract

This study suggests a modified model of TNFR1-induced complex I-mediated NFκB signaling. Evaluation of a panel of five tumor cell lines (HCT116-PIK3CAmut, SK-MEL-23, HeLa-RIPK3, HT29, D10) with TRAF2 knockout revealed in two cell lines (HT29, HeLa-RIPK3) a sensitizing effect for death receptor-induced Necroptosis and in one cell line (D10) a mild sensitization for TNFR1-induced Apoptosis. TRAF2 deficiency inhibited death receptor-induced classical NFκB-mediated production of IL-8 only in a subset of cell lines and only partly. TRAF5, furthermore, failed to improve DR-induced NFκB signaling in HCT116-PIK3CAmut and HCT116-PIK3CAmut-TRAF2KO cells. These findings argue for a non-obligatory role of TRAF2 in death receptor-induced classical NFκB signaling. Similar as in TRAF2-deficient cells, TNF- and CD95L-induced NFκB signaling was found to be only poorly affected in RIPK1KO cells and in cells treated with the RIPK1-specific PROTAC LD4172. Intriguingly, however, death receptor-induced NFκB signaling was completely inhibited in HCT116-PIK3CAmut cells double deficient for TRAF2 and RIPK1 and in TRAF2-deficient cells treated with LD4172. Moreover, with exception of recruitment of TRADD, acting upstream to TRAF2 and parallel to RIPK1, TNFR1 signaling complex formation was abrogated in TRAF2-RIPK1 DKO cells. Based on our findings, two distinguishable types of TNFR1-interacting complexes promote TNF-induced NFκB signaling: First, a TRADD-TRAF2/cIAP utilizing complex Ia which becomes evident in RIPK1-deficient cells. Second, a non-modified RIPK1 utilizing complex Ib which acts in TRADD- or TRAF2-deficient cells. Complex Ia and Ib may furthermore interact and cooperate to ubiquitinate RIPK1 resulting in a modified complex Ia/b preventing complex Ia and Ib to convert to the established TNFR1-induced cytotoxic complexes IIa and IIb.

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