The Catalytic Activity of Ubp6 Enhances Maturation of the Proteasomal Regulatory Particle
The Catalytic Activity of Ubp6 Enhances Maturation of the Proteasomal Regulatory Particle
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DOI：
10.1016/j.molcel.2011.04.021
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发表时间：
2011-06-10
期刊：
影响因子：
16
通讯作者：
Robinson, Carol V.
中科院分区：
文献类型：
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作者：
Sakata, Eri;Stengel, Florian;Robinson, Carol V.
26S蛋白酶体是一种2.5 MDa的大分子机器，负责靶向蛋白质降解。最近，四个分子伴侣被确定为促进19S调节颗粒（RP）的组装。在这里，我们探测的动态结构的蛋白酶体应用定量蛋白质组学和质谱（MS）的完整的复合物，提供详细的表征如何Ubp6协助这一组装过程。我们的MS数据表明分子伴侣和Ubp6与RP的基底部分化学计量结合。Ubp6与Hsm3的遗传相互作用，但不与其他分子伴侣，表明与Hsm3的功能重叠。我们的生化数据确定Ubp6作为Hsm3模块的额外成员。缺失ubp6与hsm3扰乱26S蛋白酶体组装，我们归因于这些组装前体上的泛素化底物的积累。因此，我们建议Ubp6通过其去泛素化活性从组装前体中清除泛素化底物来促进蛋白酶体组装。
The 26S proteasome is a 2.5 MDa macromolecular machine responsible for targeted protein degradation. Recently, four chaperones were identified that promote the assembly of the 19S regulatory particle (RP). Here, we probe the dynamic architecture of the proteasome by applying quantitative proteomics and mass spectrometry (MS) of intact complexes to provide a detailed characterization of how Ubp6 assists this assembly process. Our MS data demonstrate stoichiometric binding of chaperones and Ubp6 to the basal part of the RP. Genetic interactions of Ubp6 with Hsm3, but not with the other chaperones, indicate a functional overlay with Hsm3. Our biochemical data identified Ubp6 as an additional member of the Hsm3 module. Deletions of ubp6 with hsm3 perturb 26S proteasome assembly, which we attribute to an accumulation of ubiquitylated substrates on these assembly precursors. We therefore propose that Ubp6 facilitates proteasomal assembly by clearing ubiquitylated substrates from assembly precursors by its deubiquitylating activity.