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Abstract：
Kinesin-14s, a subfamily of the large superfamily of kinesin motor proteins, function mainly in spindle assembly and maintenance during mitosis and meiosis. KlpA from Aspergillus nidulans and GiKIN14a from Giardia intestinalis are two types of kinesin-14s. Available experimental results puzzlingly showed that while KlpA moves preferentially toward the minus end in microtubule-gliding setups and inside parallel microtubule overlaps, it moves preferentially toward the plus end on single microtubules. More puzzlingly, the insertion of an extra polypeptide linker in the central region of the neck stalk switches the motility direction of KlpA on single microtubules to the minus end. Prior experimental results showed that GiKIN14a moves preferentially toward the minus end on single microtubules in either tailless or full-length forms. The tail not only greatly enhances the processivity but also accelerates the ATPase rate and velocity of GiKIN14a. The insertion of an extra polypeptide linker in the central region of the neck stalk reduces the ATPase rate of GiKIN14a. However, the underlying mechanism of these puzzling dynamical features for KlpA and GiKIN14a is unclear. Here, to understand this mechanism, the dynamics of KlpA and GiKIN14a were studied theoretically on the basis of the proposed model, incorporating potential changes between the kinesin head and microtubule, as well as the potential between the tail and microtubule. The theoretical results quantitatively explain the available experimental results and provide predicted results. It was found that the elasticity of the neck stalk determines the directionality of KlpA on single microtubules and affects the ATPase rate and velocity of GiKIN14a on single microtubules.
摘要：
Kinesin-14s,驱动蛋白运动蛋白超家族的一个亚家族，在有丝分裂和减数分裂过程中主要作用于纺锤体的组装和维持。来自构巢曲霉的KlpA和来自肠贾第鞭毛虫的GiKIN14a是两种类型的驱动蛋白14。现有的实验结果令人费解地表明，尽管KlpA在微管滑翔设置中优先向负端移动，而在平行的微管重叠中，它优先向单个微管上的加端移动。更令人费解的是,在颈柄的中心区域中插入额外的多肽接头将KlpA在单个微管上的运动性方向转换为负端。先前的实验结果表明，GiKIN14a以无尾或全长形式优先向单个微管的负端移动。尾巴不仅大大提高了GiKIN14a的持续合成能力，而且加速了ATPase的速率和速度。在颈柄的中心区域中插入额外的多肽接头降低了GiKIN14a的ATPase率。然而,KlpA和GiKIN14a这些令人费解的动力学特征的潜在机制尚不清楚。这里,为了理解这种机制，在提出的模型的基础上，对KlpA和GiKIN14a的动力学进行了理论研究，结合驱动蛋白头和微管之间的潜在变化，以及尾巴和微管之间的电势。理论结果定量解释了可用的实验结果并提供了预测结果。发现颈柄的弹性决定了KlpA在单个微管上的方向性，并影响了单个微管上GiKIN14a的ATPase速率和速度。
