Perez-Terzic C, Pyle J, Jaconi M, Stehno-Bittel L, Clapham D E
Department of Pharmacology, Mayo Foundation, Rochester, MN 55905, USA.
Science. 1996 Sep 27;273(5283):1875-7. doi: 10.1126/science.273.5283.1875.
The nuclear pore complex (NPC) is essential for the transit of molecules between the cytoplasm and nucleoplasm of a cell and until recently was thought to allow intermediate-sized molecules (relative molecular mass of approximately 10,000) to diffuse freely across the nuclear envelope. However, the depletion of calcium from the nuclear envelope of Xenopus laevis oocytes was shown to regulate the passage of intermediate-sized molecules. Two distinct conformational states of the NPC were observed by field emission scanning electron microscopy and atomic force microscopy. A central plug occluded the NPC channel after nuclear calcium stores had been depleted and free diffusion of intermediate-sized molecules had been blocked. Thus, the NPC conformation appears to gate molecular movement across the nuclear envelope.
核孔复合体（NPC）对于细胞胞质与核质之间分子的运输至关重要，直到最近人们还认为它能让中等大小的分子（相对分子质量约为10,000）自由扩散穿过核膜。然而，研究表明非洲爪蟾卵母细胞核膜中钙的耗尽会调节中等大小分子的通过。通过场发射扫描电子显微镜和原子力显微镜观察到NPC有两种不同的构象状态。在核钙储存耗尽且中等大小分子的自由扩散被阻断后，一个中央栓堵塞了NPC通道。因此，NPC的构象似乎控制着分子穿过核膜的运动。
