Cryptochrome 2 and phototropin 2 regulate resistance protein-mediated viral defense by negatively regulating an E3 ubiquitin ligase
Cryptochrome 2 and phototropin 2 regulate resistance protein-mediated viral defense by negatively regulating an E3 ubiquitin ligase
复制标题
DOI：
10.1073/pnas.1004529107
复制
发表时间：
2010-07-27
影响因子：
11.1
通讯作者：
Kachroo, Pradeep
中科院分区：
文献类型：
--
作者：
Jeong, Rae-Dong;Chandra-Shekara, A. C.;Kachroo, Pradeep
植物收获的光对大多数生命形式的生存至关重要。这种光感知能力需要称为光感受器的蛋白质的活动。我们报道了光感受器在介导抗性(R)蛋白衍生的植物防御中的作用。蓝光光感受器隐色素（cry2）和趋光素（PHOT） 2是R蛋白HRT稳定性和对萝卜皱病毒（TCV）抗性的必需物质。暴露在黑暗或蓝光下会导致CRY2的降解，进而导致HRT的降解，从而导致易感性。HRT的过表达可以弥补PHOT2的缺失，但不能弥补CRY2的缺失。HRT不直接与CRY2或PHOT2结合，但可以结合CRY2-/PHOT2相互作用的E3泛素连接酶COP1。应用蛋白酶体抑制剂MG132可以阻止蓝光依赖性HRT的降解，因此这些植物在蓝光下表现出对TCV的抗性。我们认为CRY2/PHOT2可能通过COP1负性调节蛋白酶体介导的HRT降解，而蓝光可以缓解这种抑制，从而导致HRT降解。
Light harvested by plants is essential for the survival of most life forms. This light perception ability requires the activities of proteins termed photoreceptors. We report a function for photoreceptors in mediating resistance (R) protein-derived plant defense. The blue-light photoreceptors, cryptochrome (CRY) 2 and phototropin (PHOT) 2, are required for the stability of the R protein HRT, and thereby resistance to Turnip Crinkle virus (TCV). Exposure to darkness or blue-light induces degradation of CRY2, and in turn HRT, resulting in susceptibility. Overexpression of HRT can compensate for the absence of PHOT2 but not CRY2. HRT does not directly associate with either CRY2 or PHOT2 but does bind the CRY2-/PHOT2-interacting E3 ubiquitin ligase, COP1. Application of the proteasome inhibitor, MG132, prevents blue-light-dependent degradation of HRT, consequently these plants show resistance to TCV under blue-light. We propose that CRY2/PHOT2 negatively regulate the proteasome-mediated degradation of HRT, likely via COP1, and blue-light relieves this repression resulting in HRT degradation.