大分子（蛋白質(zhì)和核酸）在細(xì)胞核質(zhì)間的分布是真核細(xì)胞中最重要的生理功能之一，它在信號傳遞,，基因轉(zhuǎn)錄與調(diào)控，信使RNA的分布和核糖體的組裝及分布等生理過程中起關(guān)鍵的調(diào)控作用,。
Arx蛋白質(zhì)是一個與細(xì)胞分化和組織發(fā)育中至關(guān)重要的含homeodomain轉(zhuǎn)錄因子,，它的功能正常與否與腦，胰腺和睪丸的發(fā)育和功能密切相關(guān),。廈門大學(xué)陶濤教授實驗室首次系統(tǒng)地研究了Arx通過不同入核途徑在細(xì)胞核定位的分子機理和及其調(diào)控方式,，對進(jìn)一步研究Arx的生理功能提供了重要的幫助。（生物谷Bioon.com）
生物谷推薦原始出處：
JBC, published June 3, 2009 as doi:10.1074/jbc.M109.004242
The roles of multiple importins for nuclear import of murine aristaless-related homeobox protein
Wenbo Lin1, Wenduo Ye1, Lanlan Cai1, Xinyi Meng1, Guifen Ke1, Caoxin Huang1, Zi Peng1, Yinhua Yu2, Jeffrey A. Golden3, Alan M. Tartakoff4, and Tao Tao15
From the 1 Xiamen University, China; , 2 University of Houston, China; , 3 University of Pennsylvania, China; , 4 Case Western Reserve University, China
Nuclear import of proteins with nuclear localization signals (NLSs) is mediated by shuttling carriers, the importins. Some cargoes display more than a single NLS, and among these are homeodomain proteins such as Arx, which is critical for development of multiple tissues. Arx has two functional NLSs. The present studies show that several pathways can import Arx via its NLS2, which is within its DNA-binding homeodomain. Using an in vitro nuclear import assay we show that import of Arx via NLS2 can be mediated by importin β1, importin 9 or importin 13, with binding being strongest to importin β1. All binding is sensitive to RanGTP. Experiments based on precise domain deletions indicate that NLS2 binds impβ1, imp9 and imp13 and includes both an importin-binding subdomain and a regulatory subdomain with arginine residues being important for function. Moreover, Arx can be co-precipitated with these importins when NLS2 is present. Although nuclear import of Arx can be mediated by these three importin βs, importin β1 seems to play the major role, judging from in vivo siRNA ablations and the in vitro import assay. This is the first evidence to show the role of importin β1 in nuclear import of paired-type homeodomain proteins. We propose a novel and possibly quite general mechanism for nuclear import of paired-type homeodomain proteins which are critical for development.
