Ribbeck K, Görlich D
ZMBH, INF 282, 69120 Heidelberg, Germany.
EMBO J. 2001 Mar 15;20(6):1320-30. doi: 10.1093/emboj/20.6.1320.
The mechanism of facilitated translocation through nuclear pore complexes (NPCs) is only poorly understood. Here, we present a kinetic analysis of the process using various model substrates. We find that the translocation capacity of NPCs is unexpectedly high, with a single NPC allowing a mass flow of nearly 100 MDa/s and rates in the order of 10(3) translocation events per second. Our data further indicate that high affinity interactions between the translocation substrate and NPC components are dispensable for translocation. We propose a 'selective phase model' that could explain how NPCs function as a permeability barrier for inert molecules and yet become selectively permeable for nuclear transport receptors and receptor-cargo complexes.
核孔复合体（NPCs）介导的易位机制目前仍知之甚少。在此，我们使用各种模型底物对该过程进行了动力学分析。我们发现，NPCs的易位能力出乎意料地高，单个NPC允许近100 MDa/s的质量流，每秒有10³次易位事件。我们的数据进一步表明，易位底物与NPC成分之间的高亲和力相互作用对于易位并非必需。我们提出了一个“选择性相模型”，该模型可以解释NPCs如何作为惰性分子的渗透屏障，同时又对核转运受体和受体-货物复合物具有选择性通透性。
