Recruitment of TNF receptor 1 to lipid rafts is essential for TNFalpha-mediated NF-kappaB activation.
Engagement of TNF receptor 1 by TNFalpha activates the transcription factor NF-kappaB but can also induce apoptosis. Here we show that upon TNFalpha binding, TNFR1 translocates to cholesterol- and sphingolipid-enriched membrane microdomains, termed lipid rafts, where it associates with the Ser/Thr kinase RIP and the adaptor proteins TRADD and TRAF2, forming a signaling complex. In lipid rafts, TNFR1 and RIP are ubiquitylated. Furthermore, we provide evidence that translocation to lipid rafts precedes ubiquitylation, which leads to the degradation via the proteasome pathway. Interfering with lipid raft organization not only abolishes ubiquitylation but switches TNFalpha signaling from NF-kappaB activation to apoptosis. We suggest that lipid rafts are crucial for the outcome of TNFalpha-activated signaling pathways.
Legler
Daniel F
DF
Institute of Biochemistry, University of Lausanne, BIL Biomedical Research Center, CH-1066 Epalinges, Switzerland. daniel.legler@uni-konstanz.de
Micheau
Olivier
O
Doucey
Marie-Agnès
MA
Tschopp
Jürg
J
Bron
Claude
C
D015703:Antigens, CD / Q000378:metabolism*; D002460:Cell Line; D053222:Fas Ligand Protein; D006801:Humans; D066298:In Vitro Techniques; D008562:Membrane Glycoproteins / Q000378:metabolism; D021962:Membrane Microdomains / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I; D015398:Signal Transduction / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D025801:Ubiquitin / Q000378:metabolism
D015703:Antigens, CD; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; D025801:Ubiquitin