Bacterial intermediate filaments: in vivo assembly, organization, and dynamics of crescentin
Bacterial intermediate filaments: in vivo assembly, organization, and dynamics of crescentin
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DOI：
10.1101/gad.1795509
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发表时间：
2009-05-01
影响因子：
10.5
通讯作者：
Jacobs-Wagner, Christine
中科院分区：
文献类型：
--
作者：
Charbon, Godefroid;Cabeen, Matthew T.;Jacobs-Wagner, Christine
Crescentin是一个快速增长的细菌细胞骨架蛋白家族的创始成员，以前曾提出类似于真核中间丝（IF）蛋白的结构预测和体外聚合特性。在这里，我们表明，新月形也股在体内的组装和动态IF蛋白的性质，形成稳定的丝状结构，不断将亚基沿着其长度和生长在一个非极性的方式。从头组装的新月体是双相的，并涉及细胞大小依赖性的机制，有利于横向插入新月体亚基双极纵向延伸时，结构的两端到达细胞两极的结构的长度控制。新月体蛋白结构稳定地锚定在细胞包膜上，这种细胞组织需要MreB功能，确定了MreB的新功能，并提供了一个平行的肌动蛋白在多细胞动物细胞IF组装和组织中的作用。此外，对MreB定位突变体的分析表明，在细胞伸长期间，细胞壁插入通常沿着两个相反手性的螺旋沿着发生，每个螺旋抵消另一个螺旋的扭矩。
Crescentin, which is the founding member of a rapidly growing family of bacterial cytoskeletal proteins, was previously proposed to resemble eukaryotic intermediate filament (IF) proteins based on structural prediction and in vitro polymerization properties. Here, we demonstrate that crescentin also shares in vivo properties of assembly and dynamics with IF proteins by forming stable filamentous structures that continuously incorporate subunits along their length and that grow in a nonpolar fashion. De novo assembly of crescentin is biphasic and involves a cell size-dependent mechanism that controls the length of the structure by favoring lateral insertion of crescentin subunits over bipolar longitudinal extension when the structure ends reach the cell poles. The crescentin structure is stably anchored to the cell envelope, and this cellular organization requires MreB function, identifying a new function for MreB and providing a parallel to the role of actin in IF assembly and organization in metazoan cells. Additionally, analysis of an MreB localization mutant suggests that cell wall insertion during cell elongation normally occurs along two helices of opposite handedness, each counterbalancing the other's torque.