Division of Immunogenetics, German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany.
Mol Cell. 2012 Jul 27;47(2):306-19. doi: 10.1016/j.molcel.2012.05.006. Epub 2012 Jun 7.
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.
CD95（Fas/APO-1）诱导死亡信号复合物（DISC）对于启动 CD95 介导的凋亡和非凋亡反应至关重要。CD95 DISC 包含 CD95、FADD、procaspase-8、procaspase-10 和 c-FLIP 蛋白。在 DISC 处，procaspase-8 和 procaspase-10 被激活，导致活性半胱天冬酶的形成和凋亡的启动。在这项研究中，我们分析了 CD95 DISC 的化学计量。使用定量 Western blot、质谱和数学建模，我们揭示了 DISC 处 DED 蛋白 procaspase-8/procaspase-10 和 c-FLIP 的数量是 FADD 的数倍。此外，我们的发现表明，procaspase-8、procaspase-10 和 c-FLIP 可以在 DISC 处形成 DED 链，从而能够形成二聚体并有效地激活 caspase-8。总之，我们的发现提供了对 DISC 处 caspase-8 激活和凋亡起始的更深入理解。
