Aurora A Kinase Amplifies a Midzone Phosphorylation Gradient to Promote High-Fidelity Cytokinesis.
Aurora A Kinase Amplifies a Midzone Phosphorylation Gradient to Promote High-Fidelity Cytokinesis.
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DOI：
10.1086/689591
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发表时间：
2016-08
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影响因子：
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通讯作者：
Maresca TJ
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文献类型：
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作者：
Ye AA;Torabi J;Maresca TJ
Aurora B激酶（ABK）在细胞分裂过程中从着丝粒重新定位到纺锤体中间区，在那里它被认为为细胞分裂提供了空间线索。虽然在果蝇S2细胞中抑制ABK会导致大核和多核大细胞，但通过消耗Subito（果蝇MKLP2）导致中间区ABK （mABK）错误定位不会引起显著的细胞分裂缺陷。次比托耗竭是；因此，用于研究在缺乏mABK的情况下，其他分子和冗余途径对细胞分裂的贡献。通过去除中心体（CNN RNAi）或基于着丝酶的磷酸酶梯度（Sds22 RNAi）抑制潜在的极性松弛途径，不会单独导致细胞分裂缺陷，也不会与mABK的缺失结合。Aurora A激酶（AAK）活性的破坏导致中间区组装缺陷，但对收缩环定位或细胞分裂没有显著影响。基于fret的极光激酶磷酸化传感器的活细胞成像显示，在aak抑制的细胞中，中间区底物磷酸化较少，尽管中间区活性磷酸化ABK （pABK）水平正常。有趣的是，在缺乏mABK的情况下，观察到AAK抑制后双核细胞数量增加。这些数据表明，赤道刺激而非极性松弛机制是果蝇S2细胞收缩环定位和高保真细胞分裂的主要决定因素。此外，我们提出赤道刺激主要是由非中心体微管（MTs）向皮质传递因子以及由mABK和可溶性AAK池协同活动放大的中部区衍生磷酸化梯度介导的。
Aurora B kinase (ABK) re-localizes from centromeres to the spindle midzone during cytokinesis where it is thought to provide a spatial cue for cytokinesis. While global ABK inhibition in Drosophila S2 cells results in macro- and multi-nucleated large cells, mis-localization of midzone ABK (mABK) by depletion of Subito (Drosophila MKLP2) does not cause notable cytokinesis defects. Subito depletion was; therefore, used to investigate the contribution of other molecules and redundant pathways to cytokinesis in the absence of mABK. Inhibiting potential polar relaxation pathways via removal of centrosomes (CNN RNAi) or a kinetochore-based phosphatase-gradient (Sds22 RNAi) did not result in cytokinesis defects on their own or in combination with loss of mABK. Disruption of Aurora A kinase (AAK) activity resulted in midzone assembly defects but did not significantly affect contractile ring positioning or cytokinesis. Live-cell imaging of a FRET-based aurora kinase phosphorylation sensor revealed that midzone substrates were less phosphorylated in AAK-inhibited cells, despite the fact that midzone levels of active phosphorylated ABK (pABK) were normal. Interestingly, an increased number of binucleated cells were observed following AAK inhibition in the absence of mABK. The data suggest that equatorial stimulation rather than polar relaxation mechanisms are the major determinants of contractile ring positioning and high-fidelity cytokinesis in Drosophila S2 cells. Furthermore, we propose that equatorial stimulation is mediated primarily by the delivery of factors to the cortex by non-centrosomal microtubules (MTs) as well as a midzone-derived phosphorylation gradient that is amplified by the concerted activities of mABK and a soluble pool of AAK.