MPI of Biochemistry, Am Klopferspitz 18, Martinsried, Germany.
Curr Opin Struct Biol. 2010 Apr;20(2):247-52. doi: 10.1016/j.sbi.2010.01.012. Epub 2010 Feb 18.
Protein and RNA molecules are exchanged between the nucleus and cytoplasm by members of the karyopherin beta family of transport factors. Karyopherins adopt a modular HEAT-repeat architecture and are regulated by the GTPase Ran. RanGTP acts as a signal for the nuclear compartment, dissociating molecular cargo from karyopherins that mediate nuclear import and promoting cargo uptake on those mediating nuclear export. After unraveling the mechanisms of nuclear import factors, structural studies have recently provided tremendous insights into nuclear export. The impact of RanGTP binding on the karyopherins ranges from large, global conformational changes to local, allosteric effects. A theme emerges where cargo recognition provides a molecular surveillance mechanism to prevent the transport of macromolecules in an inappropriate state.
蛋白质和 RNA 分子通过核孔复合体β家族的转运因子在细胞核和细胞质之间进行交换。核孔蛋白采用模块化的 HEAT 重复结构，并受 GTP 酶 Ran 的调节。RanGTP 作为核区的信号，将分子货物从介导核输入的核孔蛋白上解离，并促进介导核输出的核孔蛋白上货物的摄取。在揭示了核输入因子的机制之后，结构研究最近为核输出提供了巨大的见解。RanGTP 结合对核孔蛋白的影响范围从大的全局构象变化到局部的变构效应。一个主题出现了，即货物识别提供了一种分子监测机制，以防止以不合适的状态运输大分子。
