Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO.
Oncode Institute, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht, Netherlands.
J Cell Biol. 2018 Jan 2;217(1):163-177. doi: 10.1083/jcb.201707160. Epub 2017 Nov 29.
Precise regulation of kinetochore-microtubule attachments is essential for successful chromosome segregation. Central to this regulation is Aurora B kinase, which phosphorylates kinetochore substrates to promote microtubule turnover. A critical target of Aurora B is the N-terminal "tail" domain of Hec1, which is a component of the NDC80 complex, a force-transducing link between kinetochores and microtubules. Although Aurora B is regarded as the "master regulator" of kinetochore-microtubule attachment, other mitotic kinases likely contribute to Hec1 phosphorylation. In this study, we demonstrate that Aurora A kinase regulates kinetochore-microtubule dynamics of metaphase chromosomes, and we identify Hec1 S69, a previously uncharacterized phosphorylation target site in the Hec1 tail, as a critical Aurora A substrate for this regulation. Additionally, we demonstrate that Aurora A kinase associates with inner centromere protein (INCENP) during mitosis and that INCENP is competent to drive accumulation of the kinase to the centromere region of mitotic chromosomes. These findings reveal that both Aurora A and B contribute to kinetochore-microtubule attachment dynamics, and they uncover an unexpected role for Aurora A in late mitosis.
动粒-微管连接的精确调控对于成功的染色体分离至关重要。这一调控的核心是 Aurora B 激酶,它磷酸化动粒底物以促进微管周转。Aurora B 的一个关键靶标是 Hec1 的 N 端“尾巴”结构域,它是 NDC80 复合物的一个组成部分,该复合物是动粒和微管之间的力转导连接。尽管 Aurora B 被认为是动粒-微管连接的“主调控因子”,但其他有丝分裂激酶可能也有助于 Hec1 的磷酸化。在这项研究中,我们证明 Aurora A 激酶调控中期染色体的动粒-微管动力学,并且我们确定了 Hec1 S69 作为 Hec1 尾巴中以前未被描述的磷酸化靶标位点,是该调控的关键 Aurora A 底物。此外,我们证明 Aurora A 激酶在有丝分裂期间与着丝粒内蛋白(INCENP)结合,并且 INCENP 有能力将激酶驱动到有丝分裂染色体的着丝粒区域。这些发现揭示了 Aurora A 和 B 都有助于动粒-微管连接动力学,并揭示了 Aurora A 在后期有丝分裂中的一个意外作用。