cDNA cloning and functional analysis of p28 (Nas6p) and p40.5 (Nas7p), two novel regulatory subunits of the 26S proteasome
cDNA cloning and functional analysis of p28 (Nas6p) and p40.5 (Nas7p), two novel regulatory subunits of the 26S proteasome
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DOI：
10.1016/s0378-1119(98)00309-6
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发表时间：
1998-08-17
期刊：
影响因子：
3.5
通讯作者：
Tanaka, K
中科院分区：
文献类型：
--
作者：
Hori, T;Kato, S;Tanaka, K
我们采用cDNA克隆推导出完整的一级结构的p28和p40.5，两个新的亚基的PA700（也称为19S复合物），一个700 kDa的多亚基调节复合物的人26 S蛋白酶体。这些多肽由226个和376个氨基酸组成，计算分子量分别为24 428 Da和42 945 Da，等电点分别为5.68和5.46。有趣的是，p28包含五个保守的基序，称为“锚蛋白重复”，这意味着该亚基可能有助于26S蛋白酶体与其他蛋白质的相互作用。计算机辅助同源性分析显示p28和p40.5与酵母蛋白质的高度序列相似性，分别称为Nas6p和Nas7p（非ATP酶亚基6和7），其功能尚不清楚。这些酵母基因NAS6和NAS7的破坏对细胞活力没有影响，表明这两个亚基都不是酵母细胞增殖所必需的。然而，NAS7而不是NAS6破坏细胞导致对热应激的高敏感性，在37摄氏度下不能增殖。(C)1998 Elsevier Science B.V.保留所有权利。
We employed cDNA cloning to deduce the complete primary structures of p28 and p40.5, two novel subunits of PA700 (also called 19S complex), a 700 kDa multisubunit regulatory complex of the human 26S proteasome. These polypeptides consisted of 226 and 376 amino acids with calculated molecular masses of 24 428 Da and 42 945 Da, and isoelectric points of 5.68 and 5.46, respectively. Intriguingly, p28 contained five conserved motifs known as 'ankyrin repeats', implying that this subunit may contribute to interaction of the 26S proteasome with other protein(s). Computer-assisted homology analysis revealed high sequence similarities of p28 and p40.5 with yeast proteins, termed Nas6p and Nas7p (non-ATPase subunits 6 and 7), respectively, whose functions are as yet unknown. Disruption of these yeast genes, NAS6 and NAS7, had no effect on cell viability, indicating that neither of the two subunits is essential for proliferation of yeast cells. However, the NAS7, but not NAS6, disruptant cells caused high sensitivity to heat stress, being unable to proliferate at 37 degrees C. (C) 1998 Elsevier Science B.V. All rights reserved.