Molecular characteristics and interactions of the intermediate filament protein synemin -: Interactions with α-actinin may anchor synemin-containing heterofilaments
Molecular characteristics and interactions of the intermediate filament protein synemin -: Interactions with α-actinin may anchor synemin-containing heterofilaments
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DOI：
10.1074/jbc.274.41.29493
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发表时间：
1999-10-08
影响因子：
4.8
通讯作者：
Robson, RM
中科院分区：
文献类型：
--
作者：
Bellin, RM;Sernett, SW;Robson, RM
Synemin是一种细胞骨架蛋白，最初被鉴定为中间丝（IF）相关蛋白，因为它与肌细胞中的IF蛋白结蛋白和波形蛋白共定位和共纯化。我们的测序研究表明，synemin是IF蛋白超家族的一个非常大的成员（1，604个残基，182，187 Da），大部分分子由长的C-末端尾部结构域组成。分子相互作用的研究表明，纯化的synemin相互作用与结蛋白，在成熟的肌肉细胞中的主要IF蛋白，并与cy-actinin，一个完整的肌原纤维Z线蛋白。此外，表达的突触蛋白杆和尾域相互作用，分别与结蛋白和α-辅肌动蛋白。对SW 13克隆系中内源性蛋白表达的分析表明，synemin在SW13.C1 Vim+细胞中与波形蛋白Ifs共表达和共定位，但在SW13.C2 Vim -细胞中不存在。转染研究表明，synemin需要另一个IF蛋白，如波形蛋白的存在下，以组装成Ifs。考虑在手提箱中，我们的研究结果表明synemin功能作为一个组成部分的杂聚IFS和起着重要的细胞骨架交联的作用，通过连接这些IFS的细胞骨架的其他组件。横纹肌细胞中的Synemin可能使这些异丝能够帮助连接相邻肌原纤维的Z线，从而在细胞骨架的完整性中发挥重要作用。
Synemin is a cytoskeletal protein originally identified as an intermediate filament (IF)-associated protein because of its colocalization and copurification with the IF proteins desmin and vimentin in muscle cells. Our sequencing studies have shown that synemin is an unusually large member (1,604 residues, 182,187 Da) of the IF protein superfamily, with the majority of the molecule consisting of a long C-terminal tail domain. Molecular interaction studies demonstrate that purified synemin interacts with desmin, the major IF protein in mature muscle cells, and with cy-actinin, an integral myofibrillar Z-line protein. Furthermore, expressed synemin rod and tail domains interact, respectively, with desmin and a-actinin. Analysis of endogenous protein expression in SW13 clonal lines reveals that synemin is coexpressed and colocalized with vimentin Ifs in SW13.C1 vim+ cells but is absent in SW13.C2 vim - cells. Transfection studies indicate that synemin requires the presence of another IF protein, such as vimentin, in order to assemble into Ifs. Taken in tote, our results suggest synemin functions as a component of heteropolymeric Ifs and plays an important cytoskeletal cross-linking role by linking these Ifs to other components of the cytoskeleton. Synemin in striated muscle cells may enable these heterofilaments to help link Z-lines of adjacent myofibrils and, thereby, play an important role in cytoskeletal integrity.