Nanoscale mechanism of molecular transport through the nuclear pore complex as studied by scanning electrochemical microscopy.
Nanoscale mechanism of molecular transport through the nuclear pore complex as studied by scanning electrochemical microscopy.
复制标题
DOI：
10.1021/ja311080j
复制
发表时间：
2013-02-13
影响因子：
15
通讯作者：
Amemiya, Shigeru
中科院分区：
文献类型：
--
作者：
Kim, Jiyeon;Izadyar, Anahita;Nioradze, Nikoloz;Amemiya, Shigeru
核孔复合体（NPC）是一种蛋白质纳米孔，它在真核细胞的细胞核和细胞质之间通过核包膜进行分子运输。小分子（<40 kDa）通过这个多蛋白复合物的大孔扩散。由于核转运受体（如进口蛋白）与屏障形成蛋白的相互作用，带有信号肽标记的被动不渗透大分子通过纳米孔被核转运受体（如进口蛋白）陪同。目前，这种双峰运输机制还没有得到很好的理解，并由有争议的模型来描述。在此，我们报告了npc介导的分子运输通过具有不同渗透性的纳米尺度中央和外周途径的动态和空间分解机制。具体来说，我们开发了一种基于纳米间隙的扫描电化学显微镜方法，以精确测量核包膜对小探针分子（二茂铁甲基）三甲基铵的极高渗透率。有效介质理论表明，5.9 × 10−2 cm/s的被动磁导率对应于探针分子通过半径为24 nm、长度为35 nm的~22纳米孔的自由扩散。外围通道被小麦胚芽凝集素阻断，使17 nm半径的中心通道通透性降低2倍。这种凝集素也用于荧光分析，发现进口蛋白主要通过7纳米厚的外周途径而不是通过足够大的中心途径促进信号标记白蛋白的运输。我们认为这种空间选择性是由屏障形成蛋白的构象变化调控的，这些蛋白质在阻断中心通道的同时，短暂地局部扩展了不渗透的薄外围通道。
The nuclear pore complex (NPC) is the proteinaceous nanopore that solely mediates molecular transport across the nuclear envelope between the nucleus and cytoplasm of a eukaryotic cell. Small molecules (<40 kDa) diffuse through the large pore of this multiprotein complex. A passively impermeable macromolecule tagged with a signal peptide is chaperoned through the nanopore by nuclear transport receptors (e.g., importins) owing to their interactions with barrier-forming proteins. Presently, this bimodal transport mechanism is not well understood and is described by controversial models. Herein, we report on a dynamic and spatially resolved mechanism for NPC-mediated molecular transport through nanoscale central and peripheral routes with distinct permeabilities. Specifically, we develop a nanogap-based approach of scanning electrochemical microscopy to precisely measure the extremely high permeability of the nuclear envelope to a small probe molecule, (ferrocenylmethyl)trimethylammonium. Effective medium theories indicate that the passive permeability of 5.9 × 10−2 cm/s corresponds to the free diffusion of the probe molecule through ~22 nanopores with a radius of 24 nm and a length of 35 nm. Peripheral routes are blocked by wheat germ agglutinin to yield two-fold lower permeability for 17 nm-radius central routes. This lectin is also used in fluorescence assays to find that importins facilitate the transport of signal-tagged albumin mainly through the 7 nm-thick peripheral route rather than through the sufficiently large central route. We propose that this spatial selectivity is regulated by the conformational changes in barrier-forming proteins that transiently and locally expand the impermeably thin peripheral route while blocking the central route.
登录
查看更多内容
影响因子：
7.4
作者：
Guo, JD;Amemiya, S
通讯作者：
Amemiya, S
影响因子：
3.3
作者：
Li, F;Chen, Y;Shao, YH
通讯作者：
Shao, YH
影响因子：
56.9
作者：
Frey, Steffen;Richter, Ralf P.;Goerlich, Dirk
通讯作者：
Goerlich, Dirk
DOI：
10.1083/jcb.109.3.971
发表时间：
1989-09
期刊：
The Journal of cell biology
影响因子：
--
作者：
Akey CW;Goldfarb DS
通讯作者：
Goldfarb DS
影响因子：
3.3
作者：
Barker, AL;Macpherson, JV;Unwin, PR
通讯作者：
Unwin, PR