Marcus Adam I, Ambrose J Christian, Blickley Lisa, Hancock William O, Cyr Richard J
Department of Biological Sciences, Penn State, 208 Mueller Laboratory, University Park, PA 16802, USA.
Cell Motil Cytoskeleton. 2002 Jul;52(3):144-50. doi: 10.1002/cm.10045.
The microtubule cytoskeleton forms the scaffolding of the meiotic spindle. Kinesins, which bind to microtubules and generate force via ATP hydrolysis, are also thought to play a critical role in spindle assembly, maintenance, and function. The A. thaliana protein, ATK1 (formerly known as KATA), is a member of the kinesin family based on sequence similarity and is implicated in spindle assembly and/or maintenance. Thus, we want to determine if ATK1 behaves as a kinesin in vitro, and if so, determine the directionality of the motor activity and processivity character (the relationship between molecular "steps" and microtubule association). The results show that ATK1 supports microtubule movement in an ATP-dependent manner and has a minus-end directed polarity. Furthermore, ATK1 exhibits non-processive movement along the microtubule and likely requires at least four ATK1 motors bound to the microtubule to support movement. Based on these results and previous data, we conclude that ATK1 is a non-processive, minus-end directed kinesin that likely plays a role in generating forces in the spindle during meiosis.
微管细胞骨架构成了减数分裂纺锤体的支架。驱动蛋白与微管结合并通过ATP水解产生力，也被认为在纺锤体组装、维持和功能中起关键作用。基于序列相似性，拟南芥蛋白ATK1（以前称为KATA）是驱动蛋白家族的成员，并且与纺锤体组装和/或维持有关。因此，我们想确定ATK1在体外是否表现为驱动蛋白，如果是，则确定其运动活性的方向性和持续性特征（分子“步移”与微管结合之间的关系）。结果表明，ATK1以ATP依赖的方式支持微管运动，并且具有负端定向极性。此外，ATK1沿微管表现出非持续性运动，并且可能需要至少四个与微管结合的ATK1马达来支持运动。基于这些结果和先前的数据，我们得出结论，ATK1是一种非持续性、负端定向的驱动蛋白，可能在减数分裂期间纺锤体中产生力的过程中发挥作用。
