1. Stoichiometry of the CD95 Death-Inducing Signaling Complex: Experimental and Modeling Evidence for a Death Effector Domain Chain Model
- Author
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Uwe Warnken, Selcen Öztürk, Martina Schnölzer, Nicolai Fricker, Inna N. Lavrik, Peter H. Krammer, Kerstin Kammerer, Petra Richter, and Kolja Schleich
- Subjects
Death Domain Receptor Signaling Adaptor Proteins ,Fas-Associated Death Domain Protein ,Ripoptosome ,Apoptosis ,Models, Biological ,Mass Spectrometry ,Humans ,fas Receptor ,FADD ,Caspase 10 ,Molecular Biology ,Caspase ,Caspase 8 ,biology ,Cell Biology ,Models, Theoretical ,Fas receptor ,Cell biology ,Microscopy, Fluorescence ,CD95 death-inducing signaling complex ,Death-inducing signaling complex ,biology.protein ,Death effector domain ,biological phenomena, cell phenomena, and immunity ,Signal transduction ,Dimerization ,HeLa Cells ,Signal Transduction - Abstract
The CD95 (Fas/APO-1) death-inducing signaling complex (DISC) is essential for the initiation of CD95-mediated apoptotic and nonapoptotic responses. The CD95 DISC comprises CD95, FADD, procaspase-8, procaspase-10, and c-FLIP proteins. Procaspase-8 and procaspase-10 are activated at the DISC, leading to the formation of active caspases and apoptosis initiation. In this study we analyzed the stoichiometry of the CD95 DISC. Using quantitative western blots, mass spectrometry, and mathematical modeling, we reveal that the amount of DED proteins procaspase-8/procaspase-10 and c-FLIP at the DISC exceeds that of FADD by several-fold. Furthermore, our findings imply that procaspase-8, procaspase-10, and c-FLIP could form DED chains at the DISC, enabling the formation of dimers and efficient activation of caspase-8. Taken together, our findings provide an enhanced understanding of caspase-8 activation and initiation of apoptosis at the DISC.
- Published
- 2012