A 'hot-spot' mutation alters the mechanical properties of keratin filament networks
A 'hot-spot' mutation alters the mechanical properties of keratin filament networks
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DOI：
10.1038/35074576
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发表时间：
2001-05-01
影响因子：
21.3
通讯作者：
Coulombe, PA
中科院分区：
文献类型：
--
作者：
Ma, LL;Yamada, S;Coulombe, PA
角蛋白5和角蛋白14在包括表皮在内的许多复层上皮的祖基细胞中聚合形成中间丝状网络，在那里提供关键的机械支持。K5或K14的遗传突变会导致单纯性大疱性表皮松解症(EBS)，这是一种皮肤脆性疾病(1)。这种突变对K5/K14细丝内在机械性能的影响尚不清楚。在这里，我们通过使用差示干涉对比显微镜表明，K14中的“热点”突变极大地降低了重组突变细丝在交联条件下捆绑的能力。流变学分析测量了野生型和突变型角蛋白的交联液的相似的小变形力学响应。然而，这种突变显著降低了交联网络对大变形的弹性。探索细丝网络局部组织的单粒子跟踪表明，与野生型细丝相比，突变聚合物表现出高度的异质性结构。我们的结果表明，表达突变角蛋白的上皮细胞的脆弱性可能是由于角蛋白聚合物交联成功能网络的能力受损所致。
Keratins 5 and 14 polymerize to form the intermediate filament network in the progenitor basal cells of many stratified epithelia including epidermis, where it provides crucial mechanical support. Inherited mutations in K5 or K14 result in epidermolysis bullosa simplex (EBS), a skin-fragility disorder(1). The impact that such mutations exert on the intrinsic mechanical properties of K5/K14 filaments is unknown. Here we show, by using differential interference contrast microscopy, that a 'hot-spot' mutation in K14 greatly reduces the ability of reconstituted mutant filaments to bundle under crosslinking conditions. Rheological assays measure similar small-deformation mechanical responses for crosslinked solutions of wild-type and mutant keratins. The mutation, however, markedly reduces the resilience of crosslinked networks against large deformations. Single-particle tracking, which probes the local organization of filament networks, shows that the mutant polymer exhibits highly heterogeneous structures compared to those of wild-type filaments. Our results indicate that the fragility of epithelial cells expressing mutant keratin may result from an impaired ability of keratin polymers to be crosslinked into a functional network.