The 55-kDa Tumor Necrosis Factor Receptor Induces Clustering of Mitochondria through Its Membrane-proximal Region

doi:10.1074/jbc.273.16.9673

The 55-kDa Tumor Necrosis Factor Receptor Induces Clustering of Mitochondria through Its Membrane-proximal Region*

From the Department of Molecular Biology, Molecular Immunology Unit, Flanders Interuniversity Institute for Biotechnology and University of Ghent, B-9000 Ghent, Belgium

Abstract

The cytokine tumor necrosis factor (TNF) activates diverse signaling molecules resulting in gene expression, differentiation, and/or cell death. Here we report a novel feature induced by TNF, namely translocation of mitochondria from a dispersed distribution to a perinuclear cluster. Mitochondrial translocation correlated with sensitivity to the cell death-inducing activity of TNF and was mediated by the 55-kDa TNF receptor (TNF-R55), but not by Fas, indicating that the signaling pathway requires a TNF-R55-specific but death domain-independent signal. Indeed, using L929 cells that express mutant TNF-R55, we showed that the membrane-proximal region of TNF-R55 was essential for signaling to mitochondrial translocation. In the absence of translocation, the cell death response was markedly delayed, pointing to a cooperative effect on cell death. Translocation of mitochondria, although dependent on the microtubules, was not imposed by the latter and was equally induced by TNF-independent immunoinhibition of the motor protein kinesin. Additionally, immunoinhibition with antibody directed against the tail domain of kinesin synergized with TNF-induced cell death. Based on this functional mimicry, we propose that a TNF-R55 membrane-proximal region-dependent signal impedes mitochondria-associated kinesin, resulting in cooperation with the TNF-R55 death domain-induced cytotoxic response and causing the observed clustering of mitochondria.

Footnotes

↵* This work was supported in part by the Interuniversitaire Attractiepolen and the Vlaams Actiecomité voor Biotechnologie.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵‡ Fellow with the Vlaams Instituut voor de Bevordering van het Wetenschappelijk-technologisch Onderzoek in de Industrie.
↵§ Postdoctoral Researcher with the Fonds voor Wetenschappelijk Onderzoek–Vlaanderen.
↵¶ Research Director with the Fonds voor Wetenschappelijk Onderzoek–Vlaanderen.
↵‖ To whom correspondence should be addressed: Laboratory of Molecular Biology, K. L. Ledeganckstraat 35, B-9000 Ghent, Belgium. Tel.: 32-9-264-51-31; Fax: 32-9-264-53-48; E-mail:johang{at}lmb.rug.ac.be.
↵1 The abbreviations used are: ΔΨ_m, mitochondrial transmembrane potential; Ab, antibody; CHX, cycloheximide; CLSM, confocal laser scanning microscopy; DD, death domain; FITC, fluorescein isothiocyanate; hTNF, human TNF; IL-6, interleukin-6; KHC, kinesin heavy chain; mAb, monoclonal antibody; MT, microtubule; mTNF, murine TNF; NF-κB, nuclear factor κB; PI, propidium iodide; R123, rhodamine 123; ROS, reactive oxygen species; TNF, tumor necrosis factor; TNF-R55, 55-kDa TNF receptor; TNF-R75, 75-kDa TNF receptor; MEM, minimal essential medium; CHAPS, 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid.
↵2 D. Vercammen and E. Boone, unpublished data.
↵3 D. Vercammen, unpublished data.
↵4 E. Boone, unpublished data.
↵5 B. Everaerdt, personal communication.
↵6 K. De Vos, unpublished data.
- Received December 17, 1997.
- Revision received February 9, 1998.
The American Society for Biochemistry and Molecular Biology, Inc.