Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, Tokyo 125-8585, Japan.
Proteo-Science Center, Ehime University, Matsuyama 790-8577, Japan.
Int J Mol Sci. 2023 Jan 4;24(2):987. doi: 10.3390/ijms24020987.
JAV1-associated ubiquitin ligase 1 (JUL1) is a RING-type E3 ubiquitin ligase that catalyzes ubiquitination of JAV1, a jasmonate signaling repressor, in in response to herbivore attack. Here we present a new insight into the nature of JUL1 as a multi-targeting enzyme for not only JAV1 but also transcription factors (TFs) screened using in vitro and in vivo protein interaction assays. Reporter assays using protoplasts showed that the JUL1-interacting TFs (JiTFs), including ERF15, bZIP53 and ORA59, were involved in transcriptional activation of jasmonate-responsive and abscisic acid-responsive . Likewise, assays using mutant plants suggested that the 3 JiTFs were indeed responsible for transcriptional regulation of and/or , and ERF15 and ORA59 were substantially responsible for the anti-herbivore trait. In vitro protein ubiqutination assays showed that JUL1 catalyzed ubiqutination of JAV1 but not any of the TFs. This was in accord with the finding that JUL1 abolished JAV1's interference with ERF15 function, according to the reporter assay. Moreover, of great interest is our finding that ERF15 but not bZIP53 or ORA59 serves as a scaffold for the JAV1/JUL1 system, indicating that there is narrow selectivity of the transcriptional reprogramming by the JAV1/JUL1 system.
JAV1 相关泛素连接酶 1（JUL1）是一种 RING 型 E3 泛素连接酶，可催化茉莉酸信号抑制剂 JAV1 的泛素化，以响应食草动物的攻击。在这里，我们提出了一个新的观点，即 JUL1 不仅是 JAV1 的多靶点酶，也是通过体外和体内蛋白质相互作用实验筛选的转录因子（TFs）的多靶点酶。使用原生质体进行的报告基因实验表明，JUL1 相互作用的 TFs（JiTFs），包括 ERF15、bZIP53 和 ORA59，参与了茉莉酸响应和脱落酸响应的基因的转录激活。同样，使用突变体植物的实验表明，这 3 个 JiTFs 确实负责基因和/或基因的转录调控，而 ERF15 和 ORA59 则对抗食草动物特性具有重要作用。体外蛋白泛素化实验表明，JUL1 催化 JAV1 的泛素化，但不催化任何 TFs 的泛素化。这与报告基因实验的结果一致，即 JUL1 消除了 JAV1 对 ERF15 功能的干扰。此外，我们发现 ERF15 而不是 bZIP53 或 ORA59 作为 JAV1/JUL1 系统的支架，这表明 JAV1/JUL1 系统的转录重编程具有较窄的选择性。
