Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA.
Dev Biol. 2022 Mar;483:112-117. doi: 10.1016/j.ydbio.2022.01.004. Epub 2022 Jan 8.
The microtubule cytoskeleton is critical for maintenance of long and long-lived neurons. The overlapping array of microtubules extends from the major site of synthesis in the cell body to the far reaches of axons and dendrites. New materials are transported from the cell body along these neuronal roads by motor proteins, and building blocks and information about the state of affairs in other parts of the cell are returned by motors moving in the opposite direction. As motor proteins walk only in one direction along microtubules, the combination of correct motor and correctly oriented microtubules is essential for moving cargoes in the right direction. In this review, we focus on how microtubule polarity is established and maintained in neurons. At first thought, it seems that figuring out how microtubules are organized in neurons should be simple. After all, microtubules are essentially sticks with a slow-growing minus end and faster-growing plus end, and arranging sticks within the constrained narrow tubes of axons and dendrites should be straightforward. It is therefore quite surprising how many mechanisms contribute to making sure they are arranged in the correct polarity. Some of these mechanisms operate to generate plus-end-out polarity of axons, and others control mixed or minus-end-out dendrites.
微管细胞骨架对于维持长寿命神经元的稳定至关重要。微管的重叠阵列从细胞体的主要合成部位延伸到轴突和树突的遥远部位。新的物质通过动力蛋白沿着这些神经元道路从细胞体运输,而反向运动的马达则将关于细胞其他部位情况的构建块和信息送回。由于动力蛋白只能沿着微管单向行走,因此正确的马达和正确定向的微管的组合对于将货物朝正确的方向移动是必不可少的。在这篇综述中,我们重点介绍了神经元中微管极性是如何建立和维持的。乍一想,似乎要弄清楚神经元中的微管是如何组织的应该很简单。毕竟,微管本质上是带有缓慢生长的负端和快速生长的正端的棒状结构,并且在轴突和树突的受限狭窄管内排列棒状结构应该很直接。因此,有多少机制有助于确保它们以正确的极性排列,这令人相当惊讶。其中一些机制用于产生轴突的正极性,而其他机制则控制混合或负端向外的树突。