Morchoisne-Bolhy Stéphanie, Geoffroy Marie-Claude, Bouhlel Imène B, Alves Annabelle, Audugé Nicolas, Baudin Xavier, Van Bortle Kevin, Powers Maureen A, Doye Valérie
Institut Jacques Monod, CNRS UMR7592-Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France.
Institut Jacques Monod, CNRS UMR7592-Université Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France Ecole Doctorale Gènes Génomes Cellules, Université Paris Sud, 91405 Orsay, France.
Mol Biol Cell. 2015 Jun 15;26(12):2343-56. doi: 10.1091/mbc.E15-02-0060. Epub 2015 Apr 22.
Nup98 is a glycine-leucine-phenylalanine-glycine (GLFG) repeat-containing nucleoporin that, in addition to nuclear transport, contributes to multiple aspects of gene regulation. Previous studies revealed its dynamic localization within intranuclear structures known as GLFG bodies. Here we show that the mammalian Nup107-160 complex (Y-complex), a major scaffold module of the nuclear pore, together with its partner Elys, colocalizes with Nup98 in GLFG bodies. The frequency and size of GLFG bodies vary among HeLa sublines, and we find that an increased level of Nup98 is associated with the presence of bodies. Recruitment of the Y-complex and Elys into GLFG bodies requires the C-terminal domain of Nup98. During cell division, Y-Nup-containing GLFG bodies are disassembled in mitotic prophase, significantly ahead of nuclear pore disassembly. FRAP studies revealed that, unlike at nuclear pores, the Y-complex shuttles into and out of GLFG bodies. Finally, we show that within the nucleoplasm, a fraction of Nup107, a key component of the Y-complex, displays reduced mobility, suggesting interaction with other nuclear components. Together our data uncover a previously neglected intranuclear pool of the Y-complex that may underscore a yet-uncharacterized function of these nucleoporins inside the nucleus, even in cells that contain no detectable GLFG bodies.
Nup98是一种含有甘氨酸-亮氨酸-苯丙氨酸-甘氨酸（GLFG）重复序列的核孔蛋白，除了参与核运输外，还在基因调控的多个方面发挥作用。先前的研究揭示了它在被称为GLFG小体的核内结构中的动态定位。在这里，我们表明哺乳动物的Nup107-160复合物（Y复合物），即核孔的主要支架模块，与其伴侣Elys一起，在GLFG小体中与Nup98共定位。GLFG小体的频率和大小在HeLa亚系中有所不同，我们发现Nup98水平的升高与小体的存在有关。Y复合物和Elys募集到GLFG小体中需要Nup98的C末端结构域。在细胞分裂过程中，含有Y-Nup的GLFG小体在有丝分裂前期解体，明显早于核孔的解体。荧光漂白恢复（FRAP）研究表明，与在核孔处不同，Y复合物在GLFG小体中穿梭进出。最后，我们表明在核质中，Y复合物的关键成分之一Nup107的一部分显示出降低了的流动性，这表明它与其他核成分相互作用。我们的数据共同揭示了一个先前被忽视的Y复合物核内池，这可能突出了这些核孔蛋白在细胞核内尚未被描述的功能，即使在没有可检测到的GLFG小体的细胞中也是如此。
