Nuclear Transport facilitated by the Interaction Between Nuclear Pores and Carbohydrates
Nuclear Transport facilitated by the Interaction Between Nuclear Pores and Carbohydrates
复制标题
核孔和碳水化合物之间的相互作用促进核运输
作者：
S.Sekiguchi;K.Niikura;Y.Matsuo;Shige H.Yoshimura;K.Ijiro
位于核膜上的核孔是核进口的选择性屏障。大的货物分子(大于∼40kD)进入细胞核的运输通常需要核转运蛋白的帮助，如Importins，它与货物分子中的核定位信号序列结合，并通过核孔将这些分子运输到细胞核。在我们之前的论文中，我们证明了显示麦芽三糖(Glc3)的量子点(QD)可以穿过洋地黄素处理的HeLa细胞的核孔。本研究的目的是阐明显示麦芽低聚糖的量子点(麦芽低聚糖量子点)核输入的机制。在制备麦芽五糖(Glc5)和麦芽七糖(Glc7)量子点的基础上，制备了Glc3-量子点。用激光共聚焦扫描显微镜(CLSM)研究了麦芽低聚糖中葡萄糖单元数对量子点核导入速率的影响。此外，我们使用表面等离子体共振(SPR)系统分析了恶意量子点与核孔中的内部蛋白质(核孔蛋白62)的直接相互作用。我们发现，含有三个以上葡萄糖单位(Glc3、Glc5和Glc7-量子点)的麦芽糖量子点迅速进入细胞核，并且与核孔蛋白62的亲和力高于聚乙二醇组分和Glc1-量子点。这些数据表明，核孔和碳水化合物之间的相互作用是麦芽糖量子点核进口的驱动力。
The nuclear pores located on the nuclear envelope work as a selective barrier to nuclear import. The transport of large cargo molecules (larger than ∼40 kD) into the nucleus generally requires the aid of nuclear transport proteins, such as importins, which bind to nuclear localization signal (NLS) sequences in the cargo molecules and transport these molecules into the nucleus through the nuclear pore. In our previous paper, we showed that maltotriose(Glc3)-displaying quantum dots (QDs) can pass through the nuclear pore in digitonin-treated HeLa cells. The aim of this study is to clarify the mechanism of the nuclear import of maltooligosaccharide-displaying QDs (maltooligo-QDs). We prepared maltopentaose(Glc5) and maltoheptaose(Glc7)-QDs in addition to Glc3-QDs. The effect of the number of glucose units in the maltooligosaccharide on the rate of nuclear import of QDs has been explored by confocal laser scanning microscopy (CLSM). Further, we analyzed that the direct interactions of maltooligo-QDs to an internal protein in the nuclear pore (Nucleoporin62) using a surface plasmon resonance (SPR) system. We found that maltooligo-QDs with more than three glucose units (Glc3, Glc5 and Glc7-QDs) rapidly entered the cellular nucleus, and had a higher affinity to nucleoporin62 than those of PEG and Glc1-QDs. These data indicate that the interaction between nuclear pores and carbohydrates is the driving force behind the nuclear import of maltooligo-QDs.