Systems Biochemistry and Structural Biology of Microtubule End Tracking
Systems Biochemistry and Structural Biology of Microtubule End Tracking
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微管末端追踪的系统生物化学和结构生物学
DOI：
10.1016/j.bpj.2011.11.1221
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发表时间：
2012
影响因子：
3.4
通讯作者：
Maurer S
中科院分区：
文献类型：
--
作者：
Maurer S
定量荧光显微镜和冷冻电子显微镜已经成为一种强有力的方法来提取微管细胞骨架作为一个动态系统如何发挥作用的潜在规则。例如，通过这种方法，现在可以从原子到微米尺度理解在生长微管末端的调节蛋白相互作用网络的分级功能，所述微管末端围绕所谓的末端结合（EB）蛋白形成。在未来，挑战将是重建甚至更复杂的系统，以便能够直接测试我们对高阶细胞骨架功能的理解。1125-Symp有丝分裂纺锤体中心的力量JonathanHoward 1，Horatiu Fantana 1，Jacques Pecreaux 2，卡洛斯Garzon-Coral 1，Stefanie Redemann 1，Anthony A.海曼一号1马克斯·普朗克分子细胞生物学和遗传学研究所，德国德累斯顿，2遗传学和发育生物学研究所，法国雷恩。有丝分裂纺锤体的精确定位对于确定细胞分裂平面和随后将细胞内容物分配给子细胞是重要的。对不同生物体和细胞类型的研究表明了不同的定心机制：星形微管从纺锤体中生长出来并推压皮质，皮质动力蛋白马达拉动星形微管，而星形微管上的动力蛋白依赖性细胞器运输导致纺锤体上的反作用力。不同的机制导致对定心精度的不同预测，突变如何影响精度，以及与主轴定心相关的力的大小。我们利用图像处理技术精确地跟踪了在第一次细胞分裂过程中，C。线虫胚胎在针对gpr-1/2（编码皮质力发生器的激活剂的基因）的RNAi后，居中的高精度（横向于前后轴的细胞直径的< 1%）增加;这表明居中不是由依赖于gpr-1/2的皮质拉力介导的。为了测量与纺锤体定位相关的力，我们构建了一个磁镊装置，以便通过结合到胚胎中的珠子对纺锤体施加力：需要大约20 pN的力才能将纺锤体移位1 μm。这些力学实验限制了定心过程的分子模型。
222a Monday, February 27, 2012 quantitative fluorescence microscopy and cryo-electron microscopy, have become a powerful approach to extract the underlying rules of how the microtubule cytoskeleton acts as a dynamic system. For example, through this approach the hierarchical functioning of a regulatory protein interaction network at growing microtubule ends, formed around so-called end binding (EB) proteins, can now be understood from the atomic to the micrometer scale. In the future, the challenge will be to reconstitute even more complex systems to be able to test directly our understanding of higher-order cytoskeletal functions.1125-Symp The Forces that Center the Mitotic Spindle Jonathon Howard1, Horatiu Fantana1, Jacques Pecreaux2, Carlos Garzon-Coral1, Stefanie Redemann1, Anthony A. Hyman1. 1Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany, 2Institute of Genetics and Developmental Biology, Rennes, France. Precise positioning of the mitotic spindle is important for specifying the plane of cell division and the subsequent partitioning of the cell’s contents to the daughter cells. Studies on different organisms and cell types have suggested diverse centering mechanisms: astral microtubules grow out from the spindle and push against the cortex, cortical dynein motors pull on astral microtubules, and dynein-dependent organelle transport on astral microtubules leads to a reactive force on the spindle. The different mechanisms lead to different predictions for the precision of centering, how mutations effect the precision, and the magnitude of the forces associated with spindle centering. We used image processing to accurately track the position and orientation of the mitotic spindle during the first cell division in the C. elegans embryo. The high precision of centering,< 1% of cell diameter transverse to the anterior-posterior axis, increased after RNAi against gpr-1/2, genes encoding activators of the cortical force generators; this suggests that centering is not mediated by gpr-1/2-dependent cortical pulling forces. To measure the forces associated with spindle positioning, we built a magnetic tweezers apparatus so that forces could be exerted on the spindle via beads incorporated into the embryo: forces of approximately 20 pN were required to displace the spindle through 1 μm. These mechanical experiments constrain molecular models of the centering process.