O-GlcNAc modification of nuclear pore complexes accelerates bidirectional transport.-猫眼课题宝

O-GlcNAc修饰核孔复合物加速了双向运输。

DOI：

10.1083/jcb.202010141

发表时间：

2021-07-05

期刊：

The Journal of cell biology

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

Yoo TY;Mitchison TJ

来源链接：

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8091080/

核孔复合物介导核转运，并在FG重复结构域上被O-连接的N-乙酰葡糖胺（O-GlcNAc）高度修饰。使用一种新的定量活细胞成像分析，Yoo和Mitchison证明了通过O-GlcNAc修饰加速核输入和输出。大分子通过核膜的转运依赖于通过核孔复合物（NPC）的易化扩散。NPC的内部含有由苯丙氨酸-甘氨酸（FG）重复结构域制成的渗透性屏障，其选择性地促进与核转运受体（NTR）结合的货物的渗透。NPCs中的FG重复结构域是O-连接的N-乙酰葡萄糖胺（O-GlcNAc）修饰的主要位点，但这种修饰在核质转运中的功能作用尚不清楚。我们开发了基于光遗传学探针的高通量测定，以量化活体人类细胞中核输入和输出的动力学。我们发现，增加O-GlcNAc修饰的NPC加速NTR促进蛋白质在两个方向上的运输，减少修饰减慢运输。超分辨率成像显示在FG重复屏障处O-GlcNAc的强烈富集。O-GlcNAc修饰也加速了小的惰性蛋白通过NPC的被动渗透。我们的结论是，O-GlcNAc修饰通过增强FG-重复屏障的非特异性渗透性来加速核质转运，可能是通过FG重复之间的相互作用的空间抑制。

Nuclear pore complexes mediate nuclear transport and are highly modified with O-linked N-acetylglucosamine (O-GlcNAc) on FG repeat domains. Using a new quantitative live-cell imaging assay, Yoo and Mitchison demonstrate acceleration of nuclear import and export by O-GlcNAc modification. Macromolecular transport across the nuclear envelope depends on facilitated diffusion through nuclear pore complexes (NPCs). The interior of NPCs contains a permeability barrier made of phenylalanine-glycine (FG) repeat domains that selectively facilitates the permeation of cargoes bound to nuclear transport receptors (NTRs). FG-repeat domains in NPCs are a major site of O-linked N-acetylglucosamine (O-GlcNAc) modification, but the functional role of this modification in nucleocytoplasmic transport is unclear. We developed high-throughput assays based on optogenetic probes to quantify the kinetics of nuclear import and export in living human cells. We found that increasing O-GlcNAc modification of the NPC accelerated NTR-facilitated transport of proteins in both directions, and decreasing modification slowed transport. Superresolution imaging revealed strong enrichment of O-GlcNAc at the FG-repeat barrier. O-GlcNAc modification also accelerated passive permeation of a small, inert protein through NPCs. We conclude that O-GlcNAc modification accelerates nucleocytoplasmic transport by enhancing the nonspecific permeability of the FG-repeat barrier, perhaps by steric inhibition of interactions between FG repeats.