Mapping nuclear pore surface with atomic force microscopy

核孔复合物（NPCs）是跨越真核细胞核膜的蛋白质的超分子组装体。离子和大分子的运输通过这一途径进行。目前尚不清楚不同的货物是否存在不同的路线，以及这些路线的进入是否取决于NPC表面的疏水性。使用原子力显微镜（AFM）的NPC表面映射解决了这个开放性问题。单个npc的表面扫描将使用具有不同疏水或亲水性的AFM尖端以窄线间距进行。根据AFM尖端与NPC表面的相互作用（即附着力），该假设被测试了NPC表面是否由将运输路线分为无机离子（亲水路线），小有机大分子（两亲路线）和使用中央通道（疏水路线）的大型货物的区域组成。电导和荧光右旋糖酐测量的组合将用于选择性地定位单个途径。利用高分辨率原子力显微镜成像的鼻咽癌表面，我们将在鼻咽癌周围寻找假设的外周通道。该项目的目标是在单个NPC水平上更好地理解核转运过程。

Nuclear pore complexes (NPCs) are supramolecular assemblies of proteins that span the nuclear envelope of eukaryotic cells. Transport of ions and macromolecules occurs through this pathway. It is still unclear whether different routes exist for different cargos and whether the access to such routes depends on the hydrophobic properties of the NPC surface. This open question is addressed by NPC surface mapping using atomic force microscopy (AFM). Surface scans across individual NPCs will be performed with narrow line spacing using AFM tips with different hydrophobic or hydrophilic properties. Derived from the AFM tip interaction with the NPC surface (i.e. adhesion forces) the hypothesis is tested whether the NPC surface consists of zones that separate transport routes into one for inorganic ions (hydrophilic route), one for small organic macromolecules (amphiphilic route) and one for large cargo using the central channel (hydrophobic route). A combination of electrical conductance and fluorescent dextran measurements will be used to selectively localize the individual pathways. With high resolution AFM imaging of the NPC surface we will search for the postulated peripheral channels in the NPC periphery. The goal of the project is a better understanding of nuclear translocation processes at the single NPC level.