Stat1 as a component of tumor necrosis factor alpha receptor 1-TRADD signaling complex to inhibit NF-kappaB activation.
Activated tumor necrosis factor alpha (TNF-alpha) receptor 1 (TNFR1) recruits TNFR1-associated death domain protein (TRADD), which in turn triggers two opposite signaling pathways leading to caspase activation for apoptosis induction and NF-kappaB activation for antiapoptosis gene upregulation. Here we show that Stat1 is involved in the TNFR1-TRADD signaling complex, as determined by employing a novel antibody array screening method. In HeLa cells, Stat1 was associated with TNFR1 and this association was increased with TNF-alpha treatment. TNFR1 signaling factors TRADD and Fas-associated death domain protein (FADD) were also found to interact with Stat1 in a TNF-alpha-dependent process. Our in vitro recombinant protein-protein interaction studies demonstrated that Stat1 could directly interact with TNFR1 and TRADD but not with FADD. Interaction between Stat1 and receptor-interacting protein (RIP) or TNFR-associated factor 2 (TRAF2) was not detected. Examination of Stat1-deficient cells showed an apparent increase in TNF-alpha-induced TRADD-RIP and TRADD-TRAF2 complex formation, while interaction between TRADD and FADD was unaffected. As a consequence, TNF-alpha-mediated I-kappaB degradation and NF-kappaB activation were markedly enhanced in Stat1-deficient cells, whereas overexpression of Stat1 in 293T cells blocked NF-kappaB activation by TNF-alpha. Thus, Stat1 acts as a TNFR1-signaling molecule to suppress NF-kappaB activation.
Wang
Y
Y
Department of Pathology, Yale University School of Medicine, New Haven, CT 06510, USA.
Wu
T R
TR
Cai
S
S
Welte
T
T
Chin
Y E
YE
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D017209:Apoptosis / Q000502:physiology; D001692:Biological Transport; D002352:Carrier Proteins / Q000276:immunology / Q000378:metabolism; D002460:Cell Line / Q000187:drug effects; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D053200:Fas-Associated Death Domain Protein; D006801:Humans; D007120:Immunochemistry / Q000379:methods; D016328:NF-kappa B / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D050794:STAT1 Transcription Factor; D015398:Signal Transduction; D047990:TNF Receptor-Associated Factor 1; D047992:TNF Receptor-Associated Factor 2; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C505533:FADD protein, human; D053200:Fas-Associated Death Domain Protein; D016328:NF-kappa B; D011506:Proteins; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; D011993:Recombinant Fusion Proteins; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D047990:TNF Receptor-Associated Factor 1; D047992:TNF Receptor-Associated Factor 2; D015534:Trans-Activators; D014409:Tumor Necrosis Factor-alpha; C506249:RIPK1 protein, human; D053422:Receptor-Interacting Protein Serine-Threonine Kinases