标题： 体内正常甲状腺和肝脏细胞核和细胞质中Fas相关死亡结构域蛋白的定位 显示英文标题

标题： In Vivo Localization of Fas-Associated Death Domain Protein in the Nucleus and Cytoplasm of Normal Thyroid and Liver Cells

摘要： FADD（Fas相关死亡结构域）是传递凋亡信号的主要死亡受体适配器分子。 最近，FADD蛋白被发现在体外细胞系的细胞质和细胞核中均有表达。 与细胞质中的FADD不同，核中的FADD被发现可以保护细胞免于凋亡。 然而，FADD在体内的亚细胞定位仍然未知。 在这里，我们证明了FADD蛋白在体外甲状腺细胞的细胞质和细胞核中均有表达，这表明FADD蛋白的核内定位是在体内发生的相关现象。 此外，我们发现未转化甲状腺细胞的细胞核中，FADD主要定位于常染色质。 我们在体外肝脏中确认了FADD的核定位，并且发现在此器官中FADD和MBD4共同作用。 这些结果表明，FADD在至少两种小鼠器官的细胞核中具有生理表达。 这种特殊的定位为FADD在体内的新功能提供了可能，例如作为细胞死亡的抑制剂，或作为转录因子，或作为凋亡与基因组监视之间的分子联系。 显示英文摘要

摘要： FADD (Fas-associated death domain) is the main death receptor adaptor molecule that transmits apoptotic signal. Recently, FADD protein was shown to be expressed both in the cytoplasm and nucleus of in vitro cell lines. In contrast to the cytoplasmic FADD, the nuclear FADD was shown to protect cells from apoptosis. However, in vivo subcellular localization of FADD was still unknown. Here, we demonstrated that FADD protein was expressed in both cytoplasmic and nuclear compartment in ex vivo thyroid cells demonstrating that nuclear sublocalization of FADD protein was a relevant phenomenon occurring in vivo. Moreover, we showed that in the nucleus of untransformed thyroid cells FADD localized mainly on euchromatin. We confirmed the nuclear localization of FADD in ex vivo liver and showed that in this organ FADD and MBD4 interact together. These results demonstrate that FADD is physiologically expressed in the nucleus of cells in at least two mouse organs. This particular localization opens new possible role of FADD in vivo either asan inhibitor of cell death, or as a transcription factor, or as a molecular link between apoptosis and genome surveillance.