Amyotrophic Lateral Sclerosis-associated Proteins TDP-43 and FUS/TLS Function in a Common Biochemical Complex to Co-regulate HDAC6 mRNA
Amyotrophic Lateral Sclerosis-associated Proteins TDP-43 and FUS/TLS Function in a Common Biochemical Complex to Co-regulate HDAC6 mRNA
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DOI：
10.1074/jbc.m110.154831
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发表时间：
2010-10-29
影响因子：
4.8
通讯作者：
Tibbetts, Randal S.
中科院分区：
文献类型：
--
作者：
Kim, Sang Hwa;Shanware, Naval P.;Tibbetts, Randal S.
肌萎缩侧索硬化症（ALS）是一种无法治愈的神经退行性疾病，优先靶向运动神经元。最近发现，两种相关RNA结合蛋白TDP-43（43-kDa TAR DNA结合域蛋白）和FUS/TLS（在肉瘤中融合/在脂肪肉瘤中翻译）中的显性突变导致ALS的一个子集。与TDP-43和FUS/TLS突变相关的趋同ALS表型提示了功能关系;然而，TDP-43和FUS/TLS是否在共同的生化途径中起作用尚不清楚。在这里，我们表明，TDP-43和FUS/TLS直接相互作用，在哺乳动物细胞的内源性表达水平形成一个复合物。结合由非结构化TDP-43 C-末端结构域介导，并在300-400-kDa复合物的背景下发生，该复合物还含有与神经病理学相关的TDP-43的C-末端裂解产物。TDP-43 C-末端片段被排除在大分子量TDP-43核糖核蛋白复合物之外，但保留FUS/TLS结合活性。TDP-43-FUS/TLS复合物的功能意义通过显示TDP-43或FUS/TLS的RNAi沉默降低组蛋白去乙酰化酶（HDAC）6 mRNA的表达来确立。TDP-43和FUS/TLS在完整细胞和体外与HDAC 6 mRNA相关，竞争实验表明蛋白质占据重叠结合位点。综合研究结果表明，TDP-43和FUS/TLS在完整细胞中形成功能复合物，并表明与TDP-43和FUS/TLS突变相关的会聚ALS表型可能反映了它们参与常见的生化过程。
Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease that preferentially targets motor neurons. It was recently found that dominant mutations in two related RNA-binding proteins, TDP-43 (43-kDa TAR DNA-binding domain protein) and FUS/TLS (fused in sarcoma/translated in liposarcoma) cause a subset of ALS. The convergent ALS phenotypes associated with TDP-43 and FUS/TLS mutations are suggestive of a functional relationship; however, whether or not TDP-43 and FUS/TLS operate in common biochemical pathways is not known. Here we show that TDP-43 and FUS/TLS directly interact to form a complex at endogenous expression levels in mammalian cells. Binding was mediated by an unstructured TDP-43 C-terminal domain and occurred within the context of a 300-400-kDa complex that also contained C-terminal cleavage products of TDP-43 linked to neuropathology. TDP-43 C-terminal fragments were excluded from large molecular mass TDP-43 ribonucleoprotein complexes but retained FUS/TLS binding activity. The functional significance of TDP-43-FUS/TLS complexes was established by showing that RNAi silencing of either TDP-43 or FUS/TLS reduced the expression of histone deacetylase (HDAC) 6 mRNA. TDP-43 and FUS/TLS associated with HDAC6 mRNA in intact cells and in vitro, and competition experiments suggested that the proteins occupy overlapping binding sites. The combined findings demonstrate that TDP-43 and FUS/TLS form a functional complex in intact cells and suggest that convergent ALS phenotypes associated with TDP-43 and FUS/TLS mutations may reflect their participation in common biochemical processes.