Single kinesin-8 microtubule depolymerization activity investigated with optical tweezers

微管是高度动态的细胞细丝。微管的末端在缓慢生长和快速缩短之间交替，称为动态不稳定性。精确控制这种不稳定性对于许多细胞内过程如细胞分裂至关重要。体内和体外研究表明，导致微管不稳定的因素之一是驱动蛋白-8家族的马达蛋白。驱动蛋白-8可以通过与微管末端的相互作用，以长度依赖性的方式交联微管并使其脱髓鞘。尽管一些研究解决了驱动蛋白-8马达蛋白的功能，但驱动蛋白-8如何解聚微管的分子机制仍不清楚。一种假设是驱动蛋白-8协同作用以使微管去活化。 该提案的目的是测量解聚力和测试的合作解聚模型，通过解决单一的驱动蛋白-8马达的末端结合活性，使用高分辨率的光镊作为一个敏感的位置和力传感器。了解驱动蛋白-8末端活性的机制将为细胞分裂提供重要的见解，并对未来的癌症研究产生影响。

Microtubules are highly dynamic cellular filaments. The end of microtubules alternate between periods of slow growth and rapid shortening known as dynamic instability. An accurate control of this instability is crucial for many intracellular processes like cell division. In vivo and in vitro studies showed that one of the factors responsible for destabilizing microtubules are motor proteins of the kinesin-8 family. Kinesin-8 can cross-link microtubules and depolymerize them in a length-dependent manner by interacting with their ends. Despite several studies addressing the function of the kinesin-8 motor protein, the molecular mechanism of how kinesin-8 depolymerizes microtubules is still unclear. One hypothesis is that kinesin-8 act cooperatively to depolymerize microtubules. The aim of this proposal is to measure depolymerization forces and test the cooperative depolymerization model by resolving the end-binding activity of single kinesin-8 motors using high-resolution optical tweezers as a sensitive position and force transducer. Understanding the mechanics of kinesin-8 end activity will provide important insights for cell division with implications for future cancer research.