Fas-associated death domain-containing protein (FADD) is a classical apoptotic pathway adaptor. Further studies revealed that it also plays essential roles in nonapoptotic processes, which is assumed to be regulated by its phosphorylation. However, the exact mechanisms are still poorly understood. To study the nonapoptotic effects of FADD, a comprehensive strategy of proteomics identification combined with bioinformatic analysis was undertaken to identify proteins differentially expressed in three cell lines containing FADD and its mutant, FADD-A and FADD-D. The cell lines were thought to bear wild-type FADD, unphosphorylated FADD mimic and constitutive phosphorylated FADD mimic, respectively. A total of 47 proteins were identified to be significantly changed due to FADD phosphorylation. Network analysis using MetaCore™ identified a number of changed proteins that were involved in cellular metabolic process, including lipid metabolism, fatty acid metabolism, glycolysis, and oxidative phosphorylation. The finding that FADD-D cell line showed an increase in fatty acid oxidation argues that it could contribute to the leaner phenotype of FADD-D mice as reported previously. In addition, six proteins related to the ubiquitin-proteasome pathway were also specifically overexpressed in FADD-D cell line. Finally, the c-Myc gene represents a convergent hub lying at the center of dysregulated pathways, and was upregulated in FADD-D cells. Taken together, these studies allowed us to conclude that impaired mitochondrial function and proteolysis might play pivotal roles in the dysfunction associated with FADD phosphorylation-induced disorders.

中文翻译：

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比较蛋白质组学分析揭示了FADD在调节小鼠胚胎成纤维细胞能量代谢和蛋白水解途径中的作用。

Fas相关死亡域含蛋白（FADD）是经典的凋亡途径适应者。进一步的研究表明，它在非凋亡过程中也起着至关重要的作用，假定它受磷酸化作用的调节。但是，确切的机制仍然知之甚少。为了研究FADD的非凋亡作用，采取了蛋白质组学鉴定与生物信息学分析相结合的综合策略，以鉴定在包含FADD及其突变体FADD-A和FADD-D的三种细胞系中差异表达的蛋白质。人们认为这些细胞系分别带有野生型FADD，未磷酸化FADD模拟物和组成型磷酸化FADD模拟物。鉴定出总共47种蛋白质由于FADD磷酸化而发生了显着变化。使用MetaCore™进行的网络分析确定了许多与细胞代谢过程有关的变化蛋白质，包括脂质代谢，脂肪酸代谢，糖酵解和氧化磷酸化。FADD-D细胞系显示出脂肪酸氧化增加的发现表明，它可能有助于FADD-D小鼠更瘦的表型。另外，与泛素-蛋白酶体途径有关的六个蛋白质在FADD-D细胞系中也被特异性地过表达。最后，c-Myc基因代表位于失调途径中心的会聚枢纽，并在FADD-D细胞中被上调。综上所述，这些研究使我们得出结论，线粒体功能受损和蛋白水解可能在与FADD磷酸化诱导的疾病相关的功能障碍中起关键作用。