PDF(Pubmed)
Abstract：
The intermediate filament protein vimentin performs an essential role in cytoskeletal interplay and dynamics, mechanosensing and cellular stress responses. In pathology, vimentin is a key player in tumorigenesis, fibrosis and infection. Vimentin filaments undergo distinct and versatile reorganizations, and behave as redox sensors. The vimentin monomer possesses a central α-helical rod domain flanked by N- and C-terminal low complexity domains. Interactions between this type of domains play an important function in the formation of phase-separated biomolecular condensates, which in turn are critical for the organization of cellular components. Here we show that several oxidants, including hydrogen peroxide and diamide, elicit the remodeling of vimentin filaments into small particles. Oxidative stress elicited by diamide induces a fast dissociation of filaments into circular, motile dots, which requires the presence of the single vimentin cysteine residue, C328. This effect is reversible, and filament reassembly can occur within minutes of oxidant removal. Diamide-elicited vimentin droplets recover fluorescence after photobleaching. Moreover, fusion of cells expressing differentially tagged vimentin allows the detection of dots positive for both tags, indicating that vimentin dots merge upon cell fusion. The aliphatic alcohol 1,6-hexanediol, known to alter interactions between low complexity domains, readily dissolves diamide-elicited vimentin dots at low concentrations, in a C328 dependent manner, and hampers reassembly. Taken together, these results indicate that vimentin oxidation promotes a fast and reversible filament remodeling into biomolecular condensate-like structures, and provide primary evidence of its regulated phase separation. Moreover, we hypothesize that filament to droplet transition could play a protective role against irreversible damage of the vimentin network by oxidative stress.
摘要：
中间丝蛋白波形蛋白在细胞骨架相互作用和动力学中起重要作用，机械传感和细胞应激反应。在病理学上,波形蛋白是肿瘤发生的关键角色，纤维化和感染。波形蛋白丝经历独特而通用的重组，并表现为氧化还原传感器。波形蛋白单体具有中心α-螺旋杆状结构域,其侧翼为N-和C-末端低复杂度结构域。这类结构域之间的相互作用在相分离的生物分子缩合物的形成中起着重要的作用。这反过来对细胞成分的组织至关重要。这里我们展示了几种氧化剂，包括过氧化氢和二酰胺，引起波形蛋白丝重塑成小颗粒。二酰胺引起的氧化应激诱导细丝快速解离成圆形，活动点，这需要单个波形蛋白半胱氨酸残基的存在，C328.这种效应是可逆的,和细丝重组可以在氧化剂去除的几分钟内发生。二酰胺引发的波形蛋白液滴在光漂白后恢复荧光。此外，表达差异标记波形蛋白的细胞融合允许检测两个标记的阳性点，表明波形蛋白点在细胞融合后合并。脂肪醇1,6-己二醇，已知会改变低复杂度域之间的交互，容易溶解低浓度的二酰胺引发的波形蛋白点，以C328依赖的方式，阻碍了重新组装。一起来看,这些结果表明，波形蛋白氧化促进快速和可逆的细丝重塑为生物分子缩合样结构，并提供其调节相分离的主要证据。此外，我们假设，细丝到液滴的过渡可以起到保护作用，防止波形蛋白网络的不可逆损害由氧化应激。
