SUMO regulates the cytoplasmonuclear transport of its target protein Daxx
SUMO regulates the cytoplasmonuclear transport of its target protein Daxx
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DOI：
10.1002/jcb.20703
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发表时间：
2006-07-01
影响因子：
4
通讯作者：
Li, SSL
中科院分区：
文献类型：
--
作者：
Chen, A;Wang, PY;Li, SSL
Fas死亡结构域相关蛋白（Daxx）具有细胞核和细胞质双重功能。然而，核运输机制在很大程度上是未知的。本研究检测了Daxx的核定位信号（NLS）以及Daxx的核转运是否由小泛素相关修饰物（SUMO）介导。Daxx的两个NLS基序，富含亮氨酸（L）的核输出信号（内斯）样基序（（IXXLXXLLXL 197）-I-188）和C-末端富含赖氨酸（K）的NLS 2（氨基酸627-634）基序，通过体外sumoylation分析确定NLS 2基序上的K610和K611是Daxx的主要sumoylation位点。失活的SUMO（SUMO-A）、不能sumoylation的突变体和Daxx NLS突变体（Daxx-NESmut和Daxx NLS 2 mut）的蛋白分散在细胞质中。细胞质中分散的Daxx突变体可以通过与活性SUMO共转染而重新定位到细胞核中，而与非活性SUMO-Delta共转染则不能，这表明SUMO在调节Daxx的细胞质-核转运中起作用。然而，在与野生型Daxx共转染期间，失活的SUMO-δ也可以重新定位到细胞核，这表明SUMO调节其靶蛋白Daxx的胞质核转运不需要共价修饰。本研究表明，细胞质SUMO在增强其靶蛋白Daxx的细胞质核转运中具有生物学作用，并且可能通过非SUMO化相互作用来实现。J.细胞。98：895-911，2006. (c)2006 Wiley-Liss，Inc.
It is known that Fas death domain-associated protein (Daxx) possesses both putative nuclear and cytoplasmic functions. However, the nuclear transport mechanism is largely unknown. This study examined the nuclear location signal (NLS) of Daxx and whether the nuclear transport of Daxx was mediated by small ubiquitin-related modifier (SUMO). Two NLS motifs of Daxx, leucine (L)-rich nuclear export signal (NES)-like motif ((IXXLXXLLXL197)-I-188) and C-terminal lysine (K) rich NLS2 (amino acids 627-634) motif, were identified and the K 610 and K 611 on the NLS2 motif were characterized as the major sumoylation sites of Daxx by in vitro sumoylation analysis. Proteins of inactive SUMO (SUMO-A), a sumoylation-incompetent mutant, and Daxx NLS mutants(Daxx-NESmut and Daxx NLS2mut) were dispersed in cytoplasm. The cytoplasmic dispersed Daxx Mutants Could be relocalized to nucleus by cotransfection with active SUMO, but not with inactive SUMO-Delta, demonstrating the role of SUMO on regulating the cytoplasmonuclear transport of Daxx. However, inactive SUMO-Delta could also be relocalized to nucleus during cotransfection with wild-type Daxx, suggesting that SUMO regulation of the cytoplasmonuclear transport of its target protein Daxx does not need covalent modification. This study shows that cytoplasmic SUMO has a biological role in enhancing the cytoplasmonuclear transport of its target protein Daxx and it may be done through the non-sumoylation interactions. J. Cell. Biochem. 98: 895-911, 2006. (c) 2006 Wiley-Liss, Inc.