The ubiquitin-specific protease UBP14 is essential for early embryo development in Arabidopsis thaliana
The ubiquitin-specific protease UBP14 is essential for early embryo development in Arabidopsis thaliana
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DOI：
10.1046/j.1365-313x.2001.01106.x
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发表时间：
2001-09-01
期刊：
影响因子：
7.2
通讯作者：
Vierstra, RD
中科院分区：
文献类型：
--
作者：
Doelling, JH;Yan, N;Vierstra, RD
泛素/26 S蛋白酶体途径是真核生物选择性降解细胞质和核蛋白的主要途径。在这一途径中，泛素链与短寿命蛋白质连接，通过26 S蛋白酶体发出信号识别和分解修饰的蛋白质。在靶标降解期间或之后，所附接的多泛素链被释放，随后被泛素特异性蛋白酶（UBP）分解以再生游离的泛素单体以供再利用。在这里，我们描述了拟南芥UBP 14，可能参与这一回收过程。它的氨基酸序列与酵母UBP 14及其直向同源物人IsoT 1 -3和网柄藻UbpA最相似，并且它可以在ubp 14 Delta突变体中功能性地取代酵母UBP 14。与其直向同源物一样，AtUBP 14可以使用Lys 48分解通过α-氨基异肽键内部连接的多泛素链，并且可以处理通过α-氨基肽键连接的泛素的一些但不是全部翻译融合体。然而，与其酵母和Dictyosteroid同源物不同，AtUBP 14在拟南芥中是必需的。编码AtUBP 14的单基因中的T-DNA插入突变导致胚胎致死表型，纯合胚胎在球形阶段停止。被捕的种子具有显著增加的多泛素链水平，表明泛素再循环的缺陷。总之，这些数据表明，在植物发育早期，泛素/26 S蛋白酶体途径在一般情况下，特别是AtUBP 14的重要作用。
The ubiquitin/26S proteasome pathway is a major route for selectively degrading cytoplasmic and nuclear proteins in eukaryotes. In this pathway, chains of ubiquitins become attached to short-lived proteins, signalling recognition and breakdown of the modified protein by the 26S proteasome. During or following target degradation, the attached multi-ubiquitin chains are released and subsequently disassembled by ubiquitin-specific proteases (UBPs) to regenerate free ubiquitin monomers for re-use. Here, we describe Arabidopsis thaliana UBP14 that may participate in this recycling process. Its amino acid sequence is most similar to yeast UBP14 and its orthologues, human IsoT1-3 and Dictyostelium UbpA, and it can functionally replace yeast UBP14 in a ubp14 Delta mutant. Like its orthologues, AtUBP14 can disassemble multi-ubiquitin chains linked internally via epsilon -amino isopeptide bonds using Lys48 and can process some, but not all, translational fusions of ubiquitin linked via alpha -amino peptide bonds. However, unlike its yeast and Dictyostelium orthologues, AtUBP14 is essential in Arabidopsis. T-DNA insertion mutations in the single gene that encodes AtUBP14 cause an embryonic lethal phenotype, with the homozygous embryos arresting at the globular stage. The arrested seeds have substantially increased levels of multi-ubiquitin chains, indicative of a defect in ubiquitin recycling. Taken together, the data demonstrate an essential role for the ubiquitin/26S proteasome pathway in general and for AtUBP14 in particular during early plant development.