Two novel ubiquitin-fold modifier 1 (Ufm1)-specific proteases, UfSP1 and UfSP2
Two novel ubiquitin-fold modifier 1 (Ufm1)-specific proteases, UfSP1 and UfSP2
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DOI：
10.1074/jbc.m610590200
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发表时间：
2007-02-23
影响因子：
4.8
通讯作者：
Chung, Chin Ha
中科院分区：
文献类型：
--
作者：
Kang, Sung Hwan;Kim, Gi Ryang;Chung, Chin Ha
泛素折叠修饰因子I（Ufm 1）是最近发现的一种新的泛素样蛋白，其三级结构与泛素具有惊人的相似性。与泛素类似，它在C-末端区域具有跨物种保守的Gly残基，具有在缀合至靶蛋白之前需要在体内加工的各种氨基酸序列的延伸。在这里，我们报告的分离，克隆和表征的两个新的小鼠Ufm 1特异性蛋白酶，命名为UfSP 1和UfSP 2。UfSP 1和UfSP 2分别由217和461个氨基酸组成，它们与先前已知的蛋白酶没有序列同源性。UfSP 2存在于大多数（如果不是全部的话）多细胞生物体中，包括植物、线虫、苍蝇和哺乳动物，而UfSP 1在数据库搜索后不能在植物和线虫中找到。UfSP 1和UfSP 2切割Ufm 1的C-末端延伸，但不切割泛素或其他泛素样蛋白，如SUMO-1和ISG 15。两者都能够从Ufm 1缀合的细胞蛋白中释放Ufm 1。它们对巯基封闭剂（如N-乙基马来酰亚胺）的抑制敏感，活性位点Cys可被Ufm 1-乙烯基甲酯标记。此外，保守的Cys残基被Ser取代导致UfSP 1和UfSP 2活性完全丧失。这些结果表明UfSP 1和UfSP 2是特异性加工Ufm 1 C末端的新型巯基蛋白酶。
Ubiquitin-fold modifier I (Ufm1) is a recently identified new ubiquitin-like protein, whose tertiary structure displays a striking resemblance to ubiquitin. Similar to ubiquitin, it has a Gly residue conserved across species at the C-terminal region with extensions of various amino acid sequences that need to be processed in vivo prior to conjugation to target proteins. Here we report the isolation, cloning, and characterization of two novel mouse Ufm1-specific proteases, named UfSP1 and UfSP2. UfSP1 and UfSP2 are composed of 217 and 461 amino acids, respectively, and they have no sequence homology with previously known proteases. UfSP2 is present in most, if not all, of multicellular organisms including plant, nematode, fly, and mammal, whereas UfSP1 could not be found in plant and nematode upon data base search. UfSP1 and UfSP2 cleaved the C-terminal extension of Ufm1 but not that of ubiquitin or other ubiquitin-like proteins, such as SUMO-1 and ISG15. Both were also capable of releasing Ufm1 from Ufm1-conjugated cellular proteins. They were sensitive to inhibition by sulfhydryl-blocking agents, such as N-ethylmaleimide, and their active site Cys could be labeled with Ufm1-vinylmethylester. Moreover, replacement of the conserved Cys residue by Ser resulted in a complete loss of the UfSP1 and UfSP2 activities. These results indicate that UfSP1 and UfSP2 are novel thiol proteases that specifically process the C terminus of Ufm1.