In vitro assembly and structure of trichocyte keratin intermediate filaments: a novel role for stabilization by disulfide bonding.
In vitro assembly and structure of trichocyte keratin intermediate filaments: a novel role for stabilization by disulfide bonding.
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毛细胞角蛋白中间丝的体外组装和结构：二硫键稳定的新作用。
DOI：
10.1083/jcb.151.7.1459
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Steinert,PM
中科院分区：
文献类型：
--
作者：
Wang,H;Parry,DA;Jones,LN;Idler,WW;Marekov,LN;Steinert,PM
25年来，中间丝（IF）被认为是真核细胞骨架的普遍组成部分。历史上，第一个被鉴定的IF蛋白是20世纪60年代来自羊毛的那些，当时它们被定义为来自“微纤维”的低硫角蛋白。这些蛋白质现在被称为Ia型/IIa型上皮细胞角蛋白，其构成几种硬化上皮细胞类型的角蛋白IF。然而，迄今为止，在>40种IF蛋白的整个类别中，红细胞角蛋白仍然是唯一不能进行有效体外组装的蛋白。在本文中，我们描述了表达的小鼠Ia型和IIa型角蛋白成IF高产量的组装。在交联实验中，我们证明还原毛细胞IF内的分子排列与Ib/IIb型细胞角蛋白中的分子排列相同。然而，在体外氧化时，几个分子间二硫键的形式和分子排列重新排列成完整的羊毛的X射线衍射分析所示的模式。我们认为，重新排列的发生，因为二硫键赋予显着增加的稳定性，巨噬细胞角蛋白IF。我们的数据表明二硫键交联在稳定这些IF和含有它们的组织中的新作用。
Intermediate filaments (IF) have been recognized as ubiquitous components of the cytoskeletons of eukaryotic cells for 25 yr. Historically, the first IF proteins to be characterized were those from wool in the 1960s, when they were defined as low sulfur keratins derived from “microfibrils.” These proteins are now known as the type Ia/type IIa trichocyte keratins that constitute keratin IF of several hardened epithelial cell types. However, to date, of the entire class of >40 IF proteins, the trichocyte keratins remain the only ones for which efficient in vitro assembly remains unavailable. In this paper, we describe the assembly of expressed mouse type Ia and type IIa trichocyte keratins into IF in high yield. In cross-linking experiments, we document that the alignments of molecules within reduced trichocyte IF are the same as in type Ib/IIb cytokeratins. However, when oxidized in vitro, several intermolecular disulfide bonds form and the molecular alignments rearrange into the pattern shown earlier by x-ray diffraction analyses of intact wool. We suggest the realignments occur because the disulfide bonds confer substantially increased stability to trichocyte keratin IF. Our data suggest a novel role for disulfide bond cross linking in stabilization of these IF and the tissues containing them.