Conformational States of the Nuclear Pore Complex Induced by Depletion of Nuclear Ca2+ Stores

Science  27 Sep 1996:
Vol. 273, Issue 5283, pp. 1875-1877
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 ∼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.

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