Park Young-Hoon, Jeong Mi Suk, Park Hyun Ho, Jang Se Bok
Department of Molecular Biology, College of Natural Sciences, Pusan National University, Jangjeon-dong, Geumjeong-gu, Busan 609-735, Republic of Korea.
Biochim Biophys Acta. 2013 Jan;1834(1):292-300. doi: 10.1016/j.bbapap.2012.08.013. Epub 2012 Aug 19.
Fas-associated death domain (FADD) protein is an adapter molecule that bridges the interactions between membrane death receptors and initiator caspases. The death receptors contain an intracellular death domain (DD) which is essential to the transduction of the apoptotic signal. The kinase receptor-interacting protein 1 (RIP1) is crucial to programmed necrosis. The cell type interplay between FADD and RIP1, which mediates both necrosis and NF-κB activation, has been evaluated in other studies, but the mechanism of the interaction of the FADD and RIP1 proteins remain poorly understood. Here, we provided evidence indicating that the DD of human FADD binds to the DD of RIP1 in vitro. We developed a molecular docking model using homology modeling based on the structures of FADD and RIP1. In addition, we found that two structure-based mutants (G109A and R114A) of the FADD DD were able to bind to the RIP1 DD, and two mutations (Q169A and N171A) of FADD DD and four mutations (G595, K596, E620, and D622) of RIP1 DD disrupted the FADD-RIP1 interaction. Six mutations (Q169A, N171A, G595, K596, E620, and D622) lowered the stability of the FADD-RIP1 complex and induced aggregation that structurally destabilized the complex, thus disrupting the interaction.
Fas相关死亡结构域（FADD）蛋白是一种衔接分子，可介导膜死亡受体与起始半胱天冬酶之间的相互作用。死亡受体含有一个细胞内死亡结构域（DD），这对于凋亡信号的转导至关重要。激酶受体相互作用蛋白1（RIP1）对程序性坏死至关重要。FADD和RIP1之间的细胞类型相互作用介导坏死和NF-κB激活，在其他研究中已得到评估，但FADD和RIP1蛋白相互作用的机制仍知之甚少。在此，我们提供证据表明人FADD的DD在体外与RIP1的DD结合。我们基于FADD和RIP1的结构，利用同源建模开发了一个分子对接模型。此外，我们发现FADD DD的两个基于结构的突变体（G109A和R114A）能够与RIP1 DD结合，而FADD DD的两个突变（Q169A和N171A）以及RIP1 DD的四个突变（G595、K596、E620和D622）破坏了FADD-RIP1相互作用。六个突变（Q169A、N171A、G595、K596、E620和D622）降低了FADD-RIP1复合物的稳定性并诱导聚集，使复合物在结构上不稳定，从而破坏了相互作用。
