Multiple associated proteins regulate proteasome structure and function
Multiple associated proteins regulate proteasome structure and function
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DOI：
10.1016/s1097-2765(02)00638-x
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发表时间：
2002-09-01
期刊：
影响因子：
16
通讯作者：
Finley, D
中科院分区：
文献类型：
--
作者：
Leggett, DS;Hanna, J;Finley, D
我们已经鉴定了在亲和纯化的蛋白酶体中丰富的蛋白质，但是如先前所定义的蛋白酶体中不存在，因为在纯化过程中升高的盐浓度使它们解离。主要成分是去泛素化酶（Ubp6），泛素连接酶（Hu15）和未表征的蛋白质（Ecm29）。Ecm29将蛋白酶体核心颗粒拴在调节颗粒上。蛋白酶体结合激活Ubp6 300倍，并由Ubp6的泛素样结构域介导，这是体内功能所必需的。Ubp6识别蛋白酶体碱基及其亚基Rpn 1，表明蛋白酶体结合位置Ubp6接近底物转运通道。ubp6A突变体表现出加速的泛素周转，表明由Ubp6催化的去泛素化事件阻止泛素易位到蛋白水解核心颗粒中。
We have identified proteins that are abundant in affinity-purified proteasomes, but absent from proteasomes as previously defined because elevated salt concentrations dissociate them during purification. The major components are a deubiquitinating enzyme (Ubp6), a ubiquitin-ligase (Hu15), and an uncharacterized protein (Ecm29). Ecm29 tethers the proteasome core particle to the regulatory particle. Proteasome binding activates Ubp6 300-fold and is mediated by the ubiquitin-like domain of Ubp6, which is required for function in vivo. Ubp6 recognizes the proteasome base and its subunit Rpn1, suggesting that proteasome binding positions Ubp6 proximally to the substrate translocation channel. ubp6A mutants exhibit accelerated turnover of ubiquitin, indicating that de-ubiquitination events catalyzed by Ubp6 prevent translocation of ubiquitin into the proteolytic core particle.