Intermediate-type 20 S proteasomes in HeLa cells: "Asymmetric" subunit composition, diversity and adaptation
Intermediate-type 20 S proteasomes in HeLa cells: "Asymmetric" subunit composition, diversity and adaptation
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DOI：
10.1016/j.jmb.2007.07.038
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发表时间：
2007-10-12
影响因子：
5.6
通讯作者：
Dahlmann, Burkhardt
中科院分区：
文献类型：
--
作者：
Klare, Nicola;Seeger, Michael;Dahlmann, Burkhardt
20 S蛋白酶体是圆柱形异聚二聚体，亚基构型为α 7、β 7、β 7、α 7。用免疫亚基（β 1 i，β 2 i，β 5 i）取代含有三个活性位点的标准β亚基（β 1，β 2，β 5），可形成20 S免疫蛋白酶体，而仅部分取代可形成中间型蛋白酶体。免疫亚基的合成可由干扰素-γ诱导，其导致HeLa细胞中标准蛋白酶体的三种亚型完全转化为中间型蛋白酶体的三种亚型，这一过程导致酶的蛋白水解活性的变化。在干扰素-γ存在下生长产生用蛋白A的Fc区结合ZZ结构域标记的蛋白酶体β 1亚基的HeLa细胞。从这些细胞中，我们已经纯化20 S蛋白酶体，通过使用IgG亲和树脂和分析他们的2D PAGE。我们的研究表明，亚基替换可以局限于蛋白酶体圆柱体的一半，导致形成中间型蛋白酶体与“不对称”亚基组成。从HeLa S3细胞的细胞质、核质和微粒体中纯化的蛋白酶体的分析表明，三个隔室配备有不同亚型和亚基组成的中间型蛋白酶体，表现出不同的特异性蛋白水解活性。(C)2007爱思唯尔有限公司保留所有权利。
The 20 S proteasomes are cylinder-shaped heteromeric dimers with a subunit configuration of alpha 7, beta 7, beta 7, alpha 7. Replacement of the three active site-containing standard beta-subunits (beta 1, beta 2, beta 5) by immuno- -subunits (beta 1i, beta 2i, beta 5i) results in formation of 20 S immuno-proteasomes, while only partial replacement leads to intermediate-type proteasomes. Synthesis of immuno-subunits can be induced by interferon-gamma, which causes a complete transformation of three subtypes of standard proteasomes into three subtypes of intermediate-type proteasomes in HeLa cells, a process that results in a change in the proteolytic activities of the enzymes. HeLa cells producing the proteasome beta 1-subunit tagged with the Fc region-binding ZZ domain of protein A were grown in the presence of interferon-gamma. From these cells, we have purified 20 S proteasomes by using IgG-affinity resin and analysed them by 2D PAGE. Our study showed that subunit replacement can be confined to one half of the proteasome cylinder, resulting in the formation of intermediate-type proteasomes with "asymmetric" subunit composition. Analysis of proteasomes purified from the cytoplasm, nucleoplasm, and microsomes of HeLa S3 cells reveals that an three compartments are furnished with intermediate-type proteasomes of different subtype and subunit composition, exhibiting different specific proteolytic activities. (C) 2007 Elsevier Ltd. All rights reserved.