Assembly of type IV neuronal intermediate filaments in nonneuronal cells in the absence of preexisting cytoplasmic intermediate filaments.
Assembly of type IV neuronal intermediate filaments in nonneuronal cells in the absence of preexisting cytoplasmic intermediate filaments.
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DOI：
10.1083/jcb.122.6.1323
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发表时间：
1993-09
期刊：
影响因子：
--
通讯作者：
Liem RK
中科院分区：
文献类型：
--
作者：
Ching GY;Liem RK
我们在这里报告在体内组装的α-internexin，IV型神经元中间丝蛋白，在转染的培养细胞，比较其组装特性与那些的神经丝三联体蛋白（NF-L，NF-M，和NF-H）。与神经丝三联体蛋白一样，α-interexin与波形蛋白共同组装成细丝。为了研究这些蛋白质在没有预先存在的细丝网络的情况下的组装特征，用缺乏细胞质中间细丝的非神经元细胞系进行瞬时转染实验。结果表明，只有α-interexin能够自组装成广泛的丝状网络。相反，神经丝三联体蛋白不能在体内均聚组装成丝状阵列。在转染的细胞中，NF-L与NF-M或NF-H共组装成丝状结构，但NF-M不能与NF-H形成丝状结构。α- internexin可与转染细胞中的每种神经丝三联体蛋白共组装形成神经丝。当分别从NF-L和NF-M的尾部结构域去除除了2个和10个氨基酸残基之外的所有氨基酸残基时，所得的NF-L和NF-M缺失突变体保留了与α-interexin共组装成丝状网络的能力。这些突变体也能够与其他野生型神经丝三联体蛋白亚基形成丝。这些结果表明，NF-L和NF-M的尾部结构域对于这些蛋白质中的每一个与其他IV型中间丝蛋白的正常共组装以形成丝是必需的。
We report here on the in vivo assembly of alpha-internexin, a type IV neuronal intermediate filament protein, in transfected cultured cells, comparing its assembly properties with those of the neurofilament triplet proteins (NF-L, NF-M, and NF-H). Like the neurofilament triplet proteins, alpha-internexin coassembles with vimentin into filaments. To study the assembly characteristics of these proteins in the absence of a preexisting filament network, transient transfection experiments were performed with a non-neuronal cell line lacking cytoplasmic intermediate filaments. The results showed that only alpha-internexin was able to self-assemble into extensive filamentous networks. In contrast, the neurofilament triplet proteins were incapable of homopolymeric assembly into filamentous arrays in vivo. NF-L coassembled with either NF-M or NF-H into filamentous structures in the transfected cells, but NF-M could not form filaments with NF-H. alpha- internexin could coassemble with each of the neurofilament triplet proteins in the transfected cells to form filaments. When all but 2 and 10 amino acid residues were removed from the tail domains of NF-L and NF-M, respectively, the resulting NF-L and NF-M deletion mutants retained the ability to coassemble with alpha-internexin into filamentous networks. These mutants were also capable of forming filaments with other wild-type neurofilament triplet protein subunits. These results suggest that the tail domains of NF-L and NF-M are dispensable for normal coassembly of each of these proteins with other type IV intermediate filament proteins to form filaments.