Molecular organization of the 20S proteasome gene family from Arabidopsis thaliana.
Molecular organization of the 20S proteasome gene family from Arabidopsis thaliana.
复制标题
拟南芥 20S 蛋白酶体基因家族的分子组织。
DOI：
10.1093/genetics/149.2.677
复制
发表时间：
1998
期刊：
影响因子：
3.3
通讯作者：
Vierstra,RD
中科院分区：
文献类型：
--
作者：
Fu,H;Doelling,JH;Arendt,CS;Hochstrasser,M;Vierstra,RD
20S蛋白酶体是真核生物中的蛋白降解复合体，负责降解短命和异常的胞内蛋白质，特别是泛素结合靶标的蛋白质。700-kD络合物以中空圆柱体的形式存在，由四个堆积的环组成，催化中心位于管腔内。两个外环和两个内环分别由7个不同的α和β多肽组成，形成了α7/β7/β7/α7对称结构。在这里，我们描述了植物拟南芥20S蛋白酶体的分子组织。通过对一系列基因克隆的分析，我们确定了一个由23个基因组成的超家族，编码所有14个蛋白酶体亚基，分别命名为PAA-PAG和PBA-PBG，分别编码蛋白酶体α亚基和β亚基A-G。其中四个亚基可能由单基因编码，其余的亚基由至少两个基因组成的家族编码。α和β亚单位基因的表达似乎是协同调节的。在所测试的9个拟南芥蛋白酶体亚基基因中，有3个基因Pac1(α3)、Pac1(α5)和PbC2(β3)可以在功能上取代它们的酵母同源基因，这为20S亚基基因的跨物种互补提供了第一个证据。综上所述，这些结果表明20S蛋白酶体在真核生物中在结构和功能上是保守的，并表明拟南芥20S蛋白酶体的亚基排列与最近确定的酵母复合体的亚基排列相似。
The 20S proteasome is the proteolytic complex in eukaryotes responsible for degrading short-lived and abnormal intracellular proteins, especially those targeted by ubiquitin conjugation. The 700-kD complex exists as a hollow cylinder comprising four stacked rings with the catalytic sites located in the lumen. The two outer rings and the two inner rings are composed of seven different α and β polypeptides, respectively, giving an α7/β7/β7/α7 symmetric organization. Here we describe the molecular organization of the 20S proteasome from the plant Arabidopsis thaliana. From an analysis of a collection of cDNA and genomic clones, we identified a superfamily of 23 genes encoding all 14 of the Arabidopsis proteasome subunits, designated PAA-PAG and PBA-PBG for Proteasome Alpha and Beta subunits A–G, respectively. Four of the subunits likely are encoded by single genes, and the remaining subunits are encoded by families of at least 2 genes. Expression of the α and β subunit genes appears to be coordinately regulated. Three of the nine Arabidopsis proteasome subunit genes tested, PAC1 (α3), PAE1 (α5) and PBC2 (β3), could functionally replace their yeast orthologs, providing the first evidence for cross-species complementation of 20S subunit genes. Taken together, these results demonstrate that the 20S proteasome is structurally and functionally conserved among eukaryotes and suggest that the subunit arrangement of the Arabidopsis 20S proteasome is similar if not identical to that recently determined for the yeast complex.