The assembly pathway of the 19S regulatory particle of the yeast 26S proteasome
The assembly pathway of the 19S regulatory particle of the yeast 26S proteasome
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DOI：
10.1091/mbc.e06-07-0635
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发表时间：
2007-02-01
影响因子：
3.3
通讯作者：
Toh-e, Akio
中科院分区：
文献类型：
--
作者：
Isono, Erika;Nishihara, Kiyoshi;Toh-e, Akio
26 S蛋白酶体由20 S蛋白酶体（核心颗粒）和19 S调节颗粒组成，19 S调节颗粒由基底和盖亚结构组成，在酵母中主要定位于细胞核中。为了研究如何以及在哪里组装这个巨大的酶复合物，我们进行了生化和显微镜下表征的蛋白酶体中产生的两个盖子突变体，rpn 5 -1和rpn 7 -3，和一个碱基突变三角洲N rpn 2，酵母酿酒酵母。我们发现，虽然盖形成废除rpn 5 -1突变体细胞在限制性温度下，一个明显完整的基地产生和定位在细胞核中。相反，在Delta N rpn 2细胞中，即使在限制性温度下，也形成了一个自由盖并定位于细胞核中。这些结果表明，26 S蛋白酶体的模块，即核心颗粒，基地，和盖子，可以形成和输入到细胞核彼此独立。基于这些观察，我们提出了一个模型的酵母26 S蛋白酶体的组装过程。
The 26S proteasome consists of the 20S proteasome (core particle) and the 19S regulatory particle made of the base and lid substructures, and it is mainly localized in the nucleus in yeast. To examine how and where this huge enzyme complex is assembled, we performed biochemical and microscopic characterization of proteasomes produced in two lid mutants, rpn5-1 and rpn7-3, and a base mutant Delta N rpn2, of the yeast Saccharomyces cerevisiae. We found that, although lid formation was abolished in rpn5-1 mutant cells at the restrictive temperature, an apparently intact base was produced and localized in the nucleus. In contrast, in Delta N rpn2 cells, a free lid was formed and localized in the nucleus even at the restrictive temperature. These results indicate that the modules of the 26S proteasome, namely, the core particle, base, and lid, can be formed and imported into the nucleus independently of each other. Based on these observations, we propose a model for the assembly process of the yeast 26S proteasome.