Nebulin binding impedes mutant desmin filament assembly
Nebulin binding impedes mutant desmin filament assembly
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星云蛋白结合阻碍突变结蛋白丝组装
DOI：
10.1091/mbc.e12-11-0840
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发表时间：
1932
影响因子：
3.3
通讯作者：
Conover GM
中科院分区：
文献类型：
--
作者：
Baker LK;Gillis DC;Sharma S;Ambrus A;Herrmann H;Conover GM
结蛋白中间丝 (DIF) 形成复杂的网状结构，组织横纹肌细胞内的肌纤维。调节结蛋白与肌节关联的机制及其在结蛋白病中的作用尚不完全清楚。在这里，我们比较了星云蛋白结合对结蛋白和三种引起结蛋白病的突变型结蛋白变体（在结蛋白的头、杆或尾结构域中携带突变）（S46F、E245D 和 T453I）的装配动力学的影响。选择这些突变体是因为突变残基位于结蛋白的星云蛋白结合区域内。我们发现，虽然 Nebulin M160-164 与结蛋白四聚体复合物和成熟丝结合，但所有三个突变体在与 Nebulin 结合时都表现出显着延迟的丝组装动力学。相应地，相对于野生型结蛋白，所有三种突变体均表现出增强的星云蛋白结合亲和力和能力。电子显微照片显示，星云蛋白与体外组装的延长的正常和突变 DIF 相关。此外，我们在活细胞成像实验中光漂白后的荧光恢复中测量到突变型结蛋白 E245D 相对于野生型结蛋白显着延迟的动态。我们提出了一种机制，通过将星云蛋白保留在 Z 盘附近，突变型结蛋白可以减缓肌细胞中结蛋白的重塑。基于这些数据，我们认为对于一些形成丝线的结蛋白突变体，结蛋白病的分子病因学是由于它们与横纹肌的主要肌动蛋白结合丝蛋白星云蛋白的关联的微妙缺陷所致。
Desmin intermediate filaments (DIFs) form an intricate meshwork that organizes myofibers within striated muscle cells. The mechanisms that regulate the association of desmin to sarcomeres and their role in desminopathy are incompletely understood. Here we compare the effect nebulin binding has on the assembly kinetics of desmin and three desminopathy-causing mutant desmin variants carrying mutations in the head, rod, or tail domains of desmin (S46F, E245D, and T453I). These mutants were chosen because the mutated residues are located within the nebulin-binding regions of desmin. We discovered that, although nebulin M160–164 bound to both desmin tetrameric complexes and mature filaments, all three mutants exhibited significantly delayed filament assembly kinetics when bound to nebulin. Correspondingly, all three mutants displayed enhanced binding affinities and capacities for nebulin relative to wild-type desmin. Electron micrographs showed that nebulin associates with elongated normal and mutant DIFs assembled in vitro. Moreover, we measured significantly delayed dynamics for the mutant desmin E245D relative to wild-type desmin in fluorescence recovery after photobleaching in live-cell imaging experiments. We propose a mechanism by which mutant desmin slows desmin remodeling in myocytes by retaining nebulin near the Z-discs. On the basis of these data, we suggest that for some filament-forming desmin mutants, the molecular etiology of desminopathy results from subtle deficiencies in their association with nebulin, a major actin-binding filament protein of striated muscle.
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从变性的单体波形蛋白重建中等尺寸的丝。
影响因子：
5.6
作者：
W. Renner;Werner W. Franke;E. Schmid;Norbert Geisler;Klaus Weber;E. Mandelkow
通讯作者：
E. Mandelkow
影响因子：
5.6
作者：
Baer, Harald;Schopferer, Michael;Willenbacher, Norbert
通讯作者：
Willenbacher, Norbert
焦点粘连是角蛋白细丝前体形成的热点。
影响因子：
7.8
作者：
Windoffer, Reinhard;Kolsch, Anne;Woll, Stefan;Leube, Rudolf E
通讯作者：
Leube, Rudolf E
影响因子：
64.5
作者：
GRANGER, BL;LAZARIDES, E
通讯作者：
LAZARIDES, E
影响因子：
3.3
作者：
Pappas, Christopher T.;Bhattacharya, Nandini;Gregorio, Carol C.
通讯作者：
Gregorio, Carol C.