Yeast Ull1/Siz1 is a novel SUM01/Smt3 ligase for septin components and functions as an adaptor between conjugating enzyme and substrates
Yeast Ull1/Siz1 is a novel SUM01/Smt3 ligase for septin components and functions as an adaptor between conjugating enzyme and substrates
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DOI：
10.1074/jbc.m109295200
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发表时间：
2001-12-28
影响因子：
4.8
通讯作者：
Kikuchi, Y
中科院分区：
文献类型：
--
作者：
Takahashi, Y;Kahyo, T;Kikuchi, Y
SUMO1/Smt3是一种泛素样蛋白修饰剂，已知可以结合其他蛋白并在各种重要过程中调节其功能。与泛素偶联系统类似，SUMO/Smt3通过El（激活酶）和E2（偶联酶）的硫酯级联转移到底物赖氨酸残基上。在我们之前的报告（Takahashi， Y., Toh-e， A., and Kikuchi， Y. (2001) Gene 275, 223-231）中，我们发现出芽酵母的Siz1/Ull1 （YDR409w）是SUMO1/Smt3连接酶的强大候选者，因为SUMO1/Smt3对septin组分的修饰在Ull1突变体中被取消，Ull1与E2 （Ubc9）和底物（septin组分）相关。在这里，我们利用纯化的重组蛋白开发了一种septin组分（Cdc3）的体外Smt3偶联系统。在这个系统中，除了El (Sua1（）外，还需要Ull1（）。Uba2复合物),E2 （Ubc9）和ATP。环样结构域的半胱氨酸残基对于体内和体外的偶联都是必不可少的。此外，含有RING-like结构域的区域直接与Ubc9和Cdc3相互作用。因此，这种SUMO/Smt3连接酶作为E2和靶蛋白之间的接头起作用。
SUMO1/Smt3, a ubiquitin-like protein modifier, is known to conjugate to other proteins and modulate their functions in various important processes. Similar to the ubiquitin conjugation system, SUMO/Smt3 is transferred to substrate lysine residues through the thioester cascade of El (activating enzyme) and E2 (conjugating enzyme). In our previous report (Takahashi, Y., Toh-e, A., and Kikuchi, Y. (2001) Gene 275, 223-231), we showed that Siz1/Ull1 (YDR409w) of budding yeast, a member of the human PLAS family containing a RING-like domain, is a strong candidate for SUMO1/Smt3 ligase because the SUMO1/Smt3 modification of septin components was abolished in the ull1 mutant and Ull1 associated with E2 (Ubc9) and the substrates (septin components) in immunoprecipitation experiments. Here we have developed an in vitro Smt3 conjugation system for a septin component (Cdc3) using purified recombinant proteins. In this system, Ull1 is additionally required as well as El (Sua1(.)Uba2 complex), E2 (Ubc9), and ATP. A cysteine residue of the RING-like domain was essential for the conjugation both in vivo and in vitro. Furthermore, a region containing the RING-like domain directly interacted with Ubc9 and Cdc3. Thus, this SUMO/Smt3 ligase functions as an adaptor between E2 and the target proteins.