The JAMM motif of human deubiquitinase Poh1 is essential for cell viability
The JAMM motif of human deubiquitinase Poh1 is essential for cell viability
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DOI：
10.1158/1535-7163.mct-06-0542
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发表时间：
2007-01-01
影响因子：
5.7
通讯作者：
MacBeth, Kyle J.
中科院分区：
文献类型：
--
作者：
Gallery, Melissa;Blank, Jonathan L.;MacBeth, Kyle J.
Poh 1去泛素化酶活性是26 S蛋白酶体对多聚泛素化底物进行蛋白水解加工所必需的，将去泛素化与完全底物降解联系起来。Poh 1 RNA干扰（RNAi）在HeLa细胞中导致细胞活力的降低和多聚泛素化蛋白水平的增加，支持Poh 1和泛素蛋白酶体途径之间的联系。为了更具体地测试Poh 1的锌金属蛋白酶基序支持细胞活力和蛋白酶体功能的任何需求，我们开发了RNAi互补策略。对细胞活力和蛋白酶体活性的影响进行了评估，在细胞与RNAi的内源性Poh 1和诱导表达的野生型Poh 1或突变形式的Poh 1，其中两个保守的组氨酸的拟议的催化位点被替换为丙氨酸。我们发现，一个完整的锌金属蛋白酶基序是必不可少的细胞活力和26 S蛋白酶体功能。Poh 1作为蛋白酶体的必需酶组分，是一个有趣的肿瘤治疗药物靶点。
Poh1 deubiquitinase activity is required for proteolytic processing of polyubiquitinated substrates by the 26S proteasome, linking deubiquitination to complete substrate degradation. Poh1 RNA interference (RNAi) in HeLa cells resulted in a reduction in cell viability and an increase in polyubiquitinated protein levels, supporting the link between Poh1 and the ubiquitin proteasome pathway. To more specifically test for any requirement of the zinc metalloproteinase motif of Poh1 to support cell viability and proteasome function, we developed a RNAi complementation strategy. Effects on cell viability and proteasome activity were assessed in cells with RNAi of endogenous Poh1 and induced expression of wild-type Poh1 or a mutant form of Poh1, in which two conserved histidines of the proposed catalytic site were replaced with alanines. We show that an intact zinc metalloproteinase motif is essential for cell viability and 26S proteasome function. As a required enzymatic component of the proteasome, Poh1 is an intriguing therapeutic drug target for cancer.