Structural basis and specificity of human otubain 1-mediated deubiquitination
Structural basis and specificity of human otubain 1-mediated deubiquitination
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DOI：
10.1042/bj20081318
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发表时间：
2009-03-01
影响因子：
4.1
通讯作者：
Kessler, Benedikt M.
中科院分区：
文献类型：
--
作者：
Edelmann, Mariola J.;Iphofer, Alexander;Kessler, Benedikt M.
OTUB（otubain）1是一种人类去泛素化酶，参与介导淋巴细胞抗原反应，但其分子功能通常尚未明确。OTUB 1的结构分析表明，与其密切的同源物OTUB 2相比，其活性位点的可及性和底物结合区域的表面性质存在差异，表明调节机制抗底物特异性的变化。生物化学分析显示OTUB I优先切割Lys（48）连接的多聚泛素链，而不是Lys（63）连接的多聚泛素链，并且它能够切割NEDD 8（神经前体细胞表达的发育下调8），但不能切割SUMO（小泛素相关修饰物）1/2/3和ISG 15（干扰素化基因15）缀合物。OTUB 1和OTUB 1的功能比较表明，对泛素为基础的活性位点探针进行乙烯基甲基酯，2-氯乙基或2-溴乙基基团的C-末端的差异反应性。突变分析表明，OTUB 1中观察到的狭窄P1'位点与其优先切割Lys（48）连接的泛素链的能力相关。免疫共沉淀和MS/MS分析OTUB 1的细胞相互作用伴侣（串联质谱）实验表明，FUS [融合涉及恶性脂肪肉瘤中的t（12;6）;也称为TLS（脂肪肉瘤易位）或CHOP（CCAAT/增强子结合蛋白同源蛋白）]和RACK] [活化激酶1的受体;也称为GNB 2L 1（鸟嘌呤核苷酸结合蛋白β多肽2样1）]是含OTUB 1的复合物的一部分，指向这种去泛素化酶在RNA加工和细胞粘附/形态学中的分子功能。
OTUB (otubain) 1 is a human (deubiquitinating enzyme that is implicated in mediating lymphocyte antigen responsiveness, but whose Molecular function is generally not well defined. A structural analysis of OTUB1 shows differences in accessibility to the active site and in surface properties of the substrate-binding regions when compared with its close homologue, OTUB2, suggesting variations in regulatory mechanisms anti Substrate specificity. Biochemical analysis reveals that OTUB I has a preference for cleaving Lys(48)-linked polyubiquitin chains over Lys(63)-linked polyubiquiting chains, and it is capable of cleaving NEDD8 (neural-precursor-cell-expressed developmentally down-regulated 8), but not SUMO (small ubiquitin-related modifier) 1/2/3 and ISG15 (interferon-stiniulated gene 15) conjugates. A functional comparison of OTUB1 and OTUB1 indicated a differential reactivity towards ubiquitin-based active-site probes carrying a vinyl methyl ester, a 2-chloroethyl or a 2-bromoethyl group at the C-terminus. Mutational analysis suggested that a narrow P1' site, as observed in OTUB 1, correlates with its ability to preferentially cleave Lys(48)-linked ubiquitin chains. Analysis of cellular interaction partners of OTUB1 by co-immunoprecipitation and MS/MS (tandem mass spectrometry) experiments demonstrated that FUS [fusion involved in t(12;6) in malignant liposarcoma; also known as TLS (translocation in liposarcoma) or CHOP (CCAAT/enhancer-binding protein homologous protein)] and RACK] [receptor for activated kinase 1; also known as GNB2L1 (guanine-nucleotide-binding protein beta polypeptide 2-like 1)] are part of OTUB1-containing complexes, pointing towards a molecular function of this deubiquitinating enzyme in RNA processing and cell adhesion/morphology.