Dek40 Encodes a PBAC4 Protein Required for 20S Proteasome Biogenesis and Seed Development
Dek40 Encodes a PBAC4 Protein Required for 20S Proteasome Biogenesis and Seed Development
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Dek40 编码 20S 蛋白酶体生物发生和种子发育所需的 PBAC4 蛋白
DOI：
10.1104/pp.18.01419
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发表时间：
2019
期刊：
影响因子：
7.4
通讯作者：
Wang Gang
中科院分区：
文献类型：
--
作者：
Wang Guifeng;Fan Wei;Ou Mingyan;Wang Xuewei;Qin Hongli;Feng Fan;Du Yulong;Ni Jiacheng;Tang Jihua;Song Rentao;Wang Gang
26 S蛋白酶体是泛素-26S蛋白酶体系统（UPS）的一种重要蛋白酶复合物，通过降解标记有多聚泛素链的短寿命调节蛋白来控制许多细胞事件。20 S蛋白水解核心蛋白酶（CP）是26 S蛋白酶体的催化核心，是UPS中的中心酶。它的生物合成过程是一个多步骤和有序的方式由一系列的蛋白酶体组装分子伴侣的帮助。本研究通过图位克隆和转基因功能互补的方法鉴定了一个新的玉米籽粒突变体--缺陷型籽粒140（dek 40），该突变体编码一个定位于胞质的蛋白酶体生物发生相关伴侣蛋白4（PBAC 4）。DEK 40通过与PBAC 3相互作用参与20 S CP的生物合成。DEK 40的功能丧失显著影响20 S CP的生物合成，导致26 S蛋白酶体的活性降低。泛素组分析表明，DEK 40影响泛素化蛋白的降解，并在维持细胞蛋白质稳态中起重要作用。这些结果表明，Dek 40编码的PBAC 4分子伴侣影响20 S CP的生物合成，是玉米26 S蛋白酶体功能和种子发育所必需的。
The 26S proteasome, an essential protease complex of the ubiquitin-26S proteasome system (UPS), controls many cellular events by degrading short-lived regulatory proteins marked with polyubiquitin chains. The 20S proteolytic core protease (CP), the catalytic core of the 26S proteasome, is a central enzyme in the UPS. Its biogenesis proceeds in a multistep and orderly fashion assisted by a series of proteasome assembly chaperones. In this study, we identified a novel maize (Zea mays) kernel mutant nameddefective kernel40(dek40), which produces small, collapsed kernels and exhibits delayed embryo and endosperm development.Dek40was identified by map-based cloning and confirmed by transgenic functional complementation.Dek40encodes a putative cytosol-localized proteasome biogenesis-associated chaperone4 (PBAC4) protein. DEK40 participates in the biogenesis of the 20S CP by interacting with PBAC3. Loss-of-function of DEK40 substantially affected 20S CP biogenesis, resulting in decreased activity of the 26S proteasome. Ubiquitylome analysis indicated that DEK40 influences the degradation of ubiquitinated proteins and plays an essential role in the maintenance of cellular protein homoeostasis. These results demonstrate thatDek40encodes a PBAC4 chaperone that affects 20S CP biogenesis and is required for 26S proteasome function and seed development in maize.