Radu A, Moore M S, Blobel G
Laboratory of Cell Biology, Howard Hughes Medical Institute, Rockefeller University, New York, New York 10021, USA.
Cell. 1995 Apr 21;81(2):215-22. doi: 10.1016/0092-8674(95)90331-3.
We report the cDNA deduced primary structure of a wheat germ agglutinin-reactive nuclear pore complex (NPC) protein of rat. The protein, termed Nup98 (for nucleoporin of 98 kDa), contains numerous GLFG and FG repeats and some FXFG repeats and is thus a vertebrate member of a family of GLFG nucleoporins that were previously discovered in yeast. Immunoelectron microscopy showed Nup98 to be asymmetrically located at the nucleoplasmic side of the NPC. Nup98 functions as one of several docking site nucleoporins in a cytosolic docking activity-mediated binding of a model transport substrate. The docking site of Nup98 was mapped to its N-terminal half, which contains all of the peptide repeats. A recombinant segment of this region depleted the docking activity of cytosol. We suggest that the peptide repeat domain of Nup98, together with peptide repeat domains of other nucleoporins, forms an array of sites for mediated docking of transport substrate, and that bidirectional transport across the NPC proceeds by repeated docking and undocking reactions.
我们报道了大鼠小麦胚凝集素反应性核孔复合体（NPC）蛋白的cDNA推导的一级结构。该蛋白称为Nup98（98 kDa核孔蛋白），含有大量GLFG和FG重复序列以及一些FXFG重复序列，因此是先前在酵母中发现的GLFG核孔蛋白家族的脊椎动物成员。免疫电子显微镜显示Nup98不对称地位于NPC的核质侧。Nup98在模型转运底物的胞质对接活性介导的结合中作为几个对接位点核孔蛋白之一发挥作用。Nup98的对接位点定位于其N端的一半，该区域包含所有肽重复序列。该区域的重组片段耗尽了胞质溶胶的对接活性。我们认为，Nup98的肽重复结构域与其他核孔蛋白的肽重复结构域一起形成了转运底物介导对接的位点阵列，并且跨NPC的双向转运通过重复的对接和脱对接反应进行。
