Department of Biochemistry I, Faculty of Medicine, Georg-August-University of Göttingen, Göttingen, Germany.
J Cell Sci. 2012 Jan 1;125(Pt 1):144-54. doi: 10.1242/jcs.090316. Epub 2012 Jan 16.
Translocation of transport complexes across the nuclear envelope is mediated by nucleoporins, proteins of the nuclear pore complex that contain phenylalanine-glycine (FG) repeats as a characteristic binding motif for transport receptors. CRM1 (exportin 1), the major export receptor, forms trimeric complexes with RanGTP and proteins containing nuclear export sequences (NESs). We analyzed the role of the nucleoporin-like protein 1, NLP1 (also known as hCG1 and NUPL2) in CRM1-dependent nuclear transport. NLP1, which contains many FG repeats, localizes to the nuclear envelope and could also be mobile within the nucleus. It promotes the formation of complexes containing CRM1 and RanGTP, with or without NES-containing cargo proteins, that can be dissociated by RanBP1 and/or the cytoplasmic nucleoporin Nup214. The FG repeats of NLP1 do not play a major role in CRM1 binding. Overexpression of NLP1 promotes CRM1-dependent export of certain cargos, whereas its depletion by small interfering RNAs leads to reduced export rates. Thus, NLP1 functions as an accessory factor in CRM1-dependent nuclear protein export.
核孔复合体蛋白核孔蛋白介导转运复合物穿过核膜的转运，核孔蛋白含有苯丙氨酸-甘氨酸 (FG) 重复序列，作为转运受体的特征结合基序。CRM1（出口蛋白 1）是主要的出口受体，与 RanGTP 和含有核输出序列 (NES) 的蛋白质形成三聚体复合物。我们分析了核孔蛋白样蛋白 1（NLP1，也称为 hCG1 和 NUPL2）在 CRM1 依赖性核转运中的作用。NLP1 含有许多 FG 重复序列，定位于核膜，并且在核内也具有移动性。它促进包含 CRM1 和 RanGTP 的复合物的形成，无论是否含有含有 NES 的货物蛋白，这些复合物可以被 RanBP1 和/或细胞质核孔蛋白 Nup214 解离。NLP1 的 FG 重复序列在 CRM1 结合中不起主要作用。NLP1 的过表达促进了某些货物的 CRM1 依赖性出口，而其通过小干扰 RNA 的耗尽导致出口率降低。因此，NLP1 作为 CRM1 依赖性核蛋白输出的辅助因子发挥作用。
