Cole Charles N, Scarcelli John J
Department of Biochemistry, Dartmouth Medical School Hanover, NH 03755, USA.
Curr Opin Cell Biol. 2006 Jun;18(3):299-306. doi: 10.1016/j.ceb.2006.04.006. Epub 2006 May 8.
All movement of molecules and macromolecules between the cytoplasm and the nucleus takes place through nuclear pore complexes (NPCs), very large macromolecular complexes that are the only channels connecting these compartments. mRNA export is mediated by multiple, highly conserved protein factors that couple steps of nuclear pre-mRNA biogenesis to mRNA transport. Mature messenger ribonucleoproteins (mRNPs) diffuse from sites of transcription to NPCs, although some active genes are positioned at the nuclear periphery where they interact physically with components of NPCs. As properly processed mRNPs translocate through the pore, certain mRNP proteins are removed, probably through the enzymatic action of the DEAD-box helicase Dbp5, which binds to Nup159 and Gle1, components of the cytoplasmic filaments of the NPC. Gle1 and the phosphoinositide IP6 activate Dbp5's ATPase activity in vitro and this could provide critical spatial regulation of Dbp5 activity in vivo.
分子和大分子在细胞质与细胞核之间的所有移动都通过核孔复合体（NPC）进行，核孔复合体是非常大的大分子复合体，是连接这些区室的唯一通道。mRNA输出由多种高度保守的蛋白质因子介导，这些因子将核前体mRNA生物合成步骤与mRNA运输耦合起来。成熟的信使核糖核蛋白（mRNP）从转录位点扩散到核孔复合体，尽管一些活跃基因位于核周边，在那里它们与核孔复合体的细胞质细丝成分发生物理相互作用。当经过适当加工的mRNP通过核孔转运时，某些mRNP蛋白会被去除，可能是通过DEAD-box解旋酶Dbp5的酶促作用，Dbp5与核孔复合体细胞质细丝成分Nup159和Gle1结合。Gle1和磷酸肌醇IP6在体外激活Dbp5的ATP酶活性，这可能在体内对Dbp5活性提供关键的空间调节。
