Arabidopsis MBP1 gene encodes a conserved ubiquitin recognition component of the 26S proteasome.
Arabidopsis MBP1 gene encodes a conserved ubiquitin recognition component of the 26S proteasome.
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拟南芥 MBP1 基因编码 26S 蛋白酶体的保守泛素识别组件。
DOI：
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发表时间：
1996
影响因子：
11.1
通讯作者：
R. Vierstra
中科院分区：
文献类型：
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作者：
S. Nocker;Quinn Deveraux;Martin Rechsteiner;R. Vierstra
多泛素链连接是真核生物26 S蛋白酶体选择性降解异常多肽和许多重要调控蛋白的关键步骤。然而，26S复合物识别这种翻译后修饰的机制尚不清楚。使用合成的multiubiquitin链探针相互作用的蛋白质的表达文库，我们已经分离出一个拟南芥cDNA，指定MBP1，编码一个41 kDa的酸性蛋白表现出高亲和力的链，特别是那些含有四个或更多的泛素。基于相似的物理和免疫学性质、多泛素结合亲和力和肽序列，MBP1与人26S蛋白酶体的亚基5a同源。结构相关的蛋白质也存在于酵母、小杆线虫和其他植物物种中。考虑到它们的结合特性、与26S蛋白酶体的关联以及广泛的分布，MBP1、S5a和相关蛋白可能作为26S蛋白酶体的必需泛素识别组分起作用。
Multiubiquitin chain attachment is a key step leading to the selective degradation of abnormal polypeptides and many important regulatory proteins by the eukaryotic 26S proteasome. However, the mechanism by which the 26S complex recognizes this posttranslational modification is unknown. Using synthetic multiubiquitin chains to probe an expression library for interacting proteins, we have isolated an Arabidopsis cDNA, designated MBP1, that encodes a 41-kDa acidic protein exhibiting high affinity for chains, especially those containing four or more ubiquitins. Based on similar physical and immunological properties, multiubiquitin binding affinities, and peptide sequence, MBP1 is homologous to subunit 5a of the human 26S proteasome. Structurally related proteins also exist in yeast, Caenorhabditis, and other plant species. Given their binding properties, association with the 26S proteasome, and widespread distribution, MBP1, S5a, and related proteins likely function as essential ubiquitin recognition components of the 26S proteasome.