Volume 22, No 11, Nov 2012
ISSN: 1001-0602
EISSN: 1748-7838 2018
impact factor 17.848*
(Clarivate Analytics, 2019)
Volume 22 Issue 11, November 2012: 1562-1575
ORIGINAL ARTICLES
Chromatin-bound NLS proteins recruit membrane vesicles and nucleoporins for nuclear envelope assembly via importin-α/β
Quanlong Lu1,*, Zhigang Lu1,*, Qinying Liu1,*, Li Guov, He Ren1, Jingyan Fu1, Qing Jiang1, Paul R Clarke2 and Chuanmao Zhang1
1State Key Laboratory of Bio-membrane and Membrane Biotechnology and Key Laboratory of Cell Proliferation and Differentiation of Ministry of Education, College of Life Sciences, Peking University, Beijing 100871, China
2Division of Cancer Research, Jacqui Wood Cancer Centre, Ninewells Hospital and Medical School, University of Dundee, DD1 9SY, Scotland, UK
Correspondence: Chuanmao Zhang,(zhangcm@pku.edu.cn)
>The mechanism for nuclear envelope (NE) assembly is not fully understood. Importin-β and the small GTPase Ran have been implicated in the spatial regulation of NE assembly process. Here we report that chromatin-bound NLS (nuclear localization sequence) proteins provide docking sites for the NE precursor membrane vesicles and nucleoporins via importin-α and -β during NE assembly in
Xenopus egg extracts. We show that along with the fast recruitment of the abundant NLS proteins such as nucleoplasmin and histones to the demembranated sperm chromatin in the extracts, importin-α binds the chromatin NLS proteins rapidly. Meanwhile, importin-β binds cytoplasmic NE precursor membrane vesicles and nucleoporins. Through interacting with importin-α on the chromatin NLS proteins, importin-β targets the membrane vesicles and nucleoporins to the chromatin surface. Once encountering Ran-GTP on the chromatin generated by RCC1, importin-β preferentially binds Ran-GTP and releases the membrane vesicles and nucleoporins for NE assembly. NE assembly is disrupted by blocking the interaction between importin-α and NLS proteins with excess soluble NLS proteins or by depletion of importin-β from the extract. Our findings reveal a novel molecular mechanism for NE assembly in
Xenopus egg extracts.
Cell Research (2012) 22:1562-1575. doi:10.1038/cr.2012.113; published online 31 July 2012
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