Structural determinants of the cellular localization and shuttling of TDP-43
Structural determinants of the cellular localization and shuttling of TDP-43
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DOI：
10.1242/jcs.038950
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发表时间：
2008-11-15
影响因子：
4
通讯作者：
Baralle, Francisco E.
中科院分区：
文献类型：
--
作者：
Ayala, Youhna M.;Zago, Paola;Baralle, Francisco E.
TDP - 43（也称为TARDBP）通过与RNA和DNA结合来调控基因表达的不同过程，包括转录和剪接。此外，近期的报道表明该蛋白质与特定mRNA的3'非翻译区相互作用。最近在神经退行性疾病，即额颞叶变性（FTLD）和肌萎缩侧索硬化症（ALS）中报道了TDP - 43异常的细胞分布和聚集。关于细胞定位的决定因素，包括TDP - 43的已知功能和细胞靶向如何相互影响的信息尚未出现详细描述。我们提供了首个实验证据，表明TDP - 43以转录依赖的方式在细胞核和细胞质之间持续穿梭。此外，我们通过免疫荧光和生化分级分离方法相结合的方式研究了功能性TDP - 43结构域在决定细胞靶向中的作用。我们的分析表明，C末端对于溶解性和细胞定位至关重要，因为其缺失会导致大量细胞核和细胞质聚集体的形成。然而，破坏RNA和DNA结合所必需的RNA识别结构域会通过减少核质中TDP - 43的存在来改变核分布。我们的研究结果表明，TDP - 43的溶解性和定位对超出新发现的核定位信号的破坏特别敏感，并且取决于与该蛋白质功能特性密切相关的多种因素的组合。
TDP-43 (also known as TARDBP) regulates different processes of gene expression, including transcription and splicing, through RNA and DNA binding. Moreover, recent reports have shown that the protein interacts with the 3' UTRs of specific mRNAs. The aberrant cellular distribution and aggregation of TDP-43 were recently reported in neurodegenerative diseases, namely frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). A detailed description of the determinants for cellular localization has yet to emerge, including information on how the known functions of TDP-43 and cellular targeting affect each other. We provide the first experimental evidence that TDP-43 continuously shuttles between nucleus and cytoplasm in a transcription-dependent manner. Furthermore, we investigate the role of the functional TDP-43 domains in determining cellular targeting through a combination of immunofluorescence and biochemical fractionation methods. Our analyses indicate that the C-terminus essential for solubility and cellular localization, because its deletion results in the formation of large nuclear and cytoplasmic aggregates. Disruption of the RNA-recognition domain required for RNA and DNA binding, however, alters nuclear distribution by decreasing TDP-43 presence in the nucleoplasm. Our findings suggest that TDP-43 solubility and localization are particularly sensitive to disruptions that extend beyond the newly found nuclear localization signal and depend on a combination of factors that are closely connected to the functional properties of this protein.