Involvement of FAN in TNF-induced apoptosis
Bruno Ségui, … , Martin Krönke, Thierry Levade
Bruno Ségui, … , Martin Krönke, Thierry Levade
Published July 1, 2001
Citation Information: J Clin Invest. 2001;108(1):143-151. https://doi.org/10.1172/JCI11498.
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Involvement of FAN in TNF-induced apoptosis

Abstract

TNF-α is a pleiotropic cytokine activating several signaling pathways initiated at distinct intracellular domains of the TNF receptors. Although the C-terminal region is believed to be responsible for apoptosis induction, the functions of more membrane-proximal domains, including the domain that couples to neutral sphingomyelinase activation, are not yet fully elucidated. The roles of this region and of the associated adapter protein FAN (factor associated with neutral SMase activation) in the cytotoxic response to TNF have been investigated. We have now shown that stable expression in human fibroblasts of a dominant negative form of FAN abrogates TNF-induced ceramide generation from sphingomyelin hydrolysis and reduces caspase processing, thus markedly inhibiting TNF-triggered apoptosis. However, the cytotoxic responses to daunorubicin and exogenous ceramide remain unaltered, as do the TNF-induced p42/p44 MAPK activation and CD54 expression. Fibroblasts from FAN-knockout mice also proved to be resistant to TNF toxicity. These findings highlight the previously unrecognized role of the adapter protein FAN in signaling cell death induction by TNF.

Authors

Bruno Ségui, Olivier Cuvillier, Sabine Adam-Klages, Virginie Garcia, Sophie Malagarie-Cazenave, Sophie Lévêque, Sylvie Caspar-Bauguil, Jérôme Coudert, Robert Salvayre, Martin Krönke, Thierry Levade

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TNF-induced cell death is impaired in fibroblasts from FAN-deficient mic...
TNF-induced cell death is impaired in fibroblasts from FAN-deficient mice. SV40-transformed fibroblasts from wild-type (FAN+/+) or FAN-knockout (FAN–/–) mice were incubated for 24 hours in the presence of the indicated concentrations of daunorubicin (DNR) (a), or for 72 hours under serum-free conditions with the indicated concentrations of human TNF and without cycloheximide (b). (c) Murine FAN-deficient fibroblasts were preincubated for 72 hours in the presence of an empty retroviral vector (FAN–/–) or a retroviral vector carrying the full-length FAN cDNA (FAN–/– corrected) and were then treated for 72 hours with 10 ng/ml of human TNF. Viability of FAN–/– and FAN–/– corrected cells was assessed by MTT assay (mean ± SE of three independent experiments) and expressed as percentage of the response observed in FAN+/+ cells (see b).