GmRFP1 encodes a previously unknown RING-type E3 ubiquitin ligase in Soybean (Glycine max)
GmRFP1 encodes a previously unknown RING-type E3 ubiquitin ligase in Soybean (Glycine max)
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GmRFP1 编码大豆 (Glycine max) 中以前未知的 RING 型 E3 泛素连接酶
DOI：
10.1007/s11033-009-9535-1
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发表时间：
2010-02-01
影响因子：
2.8
通讯作者：
Yu, De-Yue
中科院分区：
文献类型：
--
作者：
Du, Qiu-Li;Cui, Wen-Zhuo;Yu, De-Yue
具有E3泛素连接酶活性的环指蛋白在植物生长发育调控中发挥重要作用。本研究从大豆中分离到一种新的环指蛋白，并对其进行了鉴定。GmRFP1是一个无内含子基因，编码392个氨基酸残基的预测蛋白产物，分子量约为43 kDa。该蛋白含有一个RING-H2基序和一个n端跨膜结构域。该转录本在所有检测器官中均有表达，在ABA和盐胁迫下表达上调，在寒冷和干旱处理下表达下调。我们进一步在大肠杆菌中表达和纯化了野生型和突变型GmRFP1。体外实验表明，纯化后的GmRFP1诱导了多泛素链的形成，而环指区突变使泛素化活性消失。这些发现表明，GmRFP1是大豆中未知的E3泛素连接酶，其活性需要环结构域。它可能通过泛素-蛋白酶体途径介导靶蛋白的泛素化和降解，在ABA信号传导和应激反应中发挥着未被认识到的作用。
RING-finger proteins with E3 ubiquitin ligase activity play important roles in the regulation of plant growth and development. In this study, a cDNA clone encoding a novel RING-finger protein, designated as GmRFP1, was isolated and characterized from soybean. GmRFP1 was an intronless gene encoding a predicted protein product of 392 amino acid residues with a molecular mass of ~43 kDa. The protein contained a RING-H2 motif and an N-terminal transmembrane domain. The transcript was observed in all detected organs and was up-regulated by abscisic acid (ABA) and salt stress, but down-regulated by cold and drought treatments. We further expressed and purified both wild type and mutant version of GmRFP1 in E. coli. In vitro assays showed that the purified GmRFP1 induced the formation of polyubiquitin chains while mutation within the RING-finger region abolished the ubiquitination activity. These findings suggest that GmRFP1 is a previously unknown E3 ubiquitin ligase in soybean and that the RING domain is required for its activity. It may play unappreciated roles in ABA signaling and stress responses via mediating the ubiquitination and degradation of target proteins through the ubiquitin-proteasome pathway.