Arabidopsis Ubiquitin Conjugase UBC32 Is an ERAD Component That Functions in Brassinosteroid-Mediated Salt Stress Tolerance
Arabidopsis Ubiquitin Conjugase UBC32 Is an ERAD Component That Functions in Brassinosteroid-Mediated Salt Stress Tolerance
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拟南芥泛素缀合酶 UBC32 是一种 ERAD 成分，在油菜素类固醇介导的盐胁迫耐受中发挥作用
DOI：
10.1105/tpc.111.093062
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发表时间：
2012-01-01
期刊：
影响因子：
11.6
通讯作者：
Xie, Qi
中科院分区：
文献类型：
--
作者：
Cui, Feng;Liu, Lijing;Xie, Qi
植物通过触发多种信号通路，包括泛素介导的蛋白质降解通路的激活，来调节其生长和发育以保护自己免受不利条件的影响。内质网（ER）相关蛋白降解（ERAD）是泛素-蛋白酶体系统的一个重要方面，但在植物中只有少数ERAD活性成分被报道。本文中，我们报道了拟南芥泛素偶联酶UBC32，一种定位于内质网膜的应激诱导功能泛素偶联酶（E2），将ERAD过程与油菜素内酯（BR）介导的生长促进和盐胁迫耐受联系起来。体内数据显示，UBC32是一种功能性ERAD成分，可影响已知ERAD底物大麦（Hordeum vulgare）白粉病O （MLO）突变体MLO-12的稳定性。UBC32突变引起BR受体BRI1的突变形式BRI1 -5和BRI1 -9的积累，这些突变形式随后激活BR信号转导。进一步的遗传和生理数据支持了UBC32在BR介导的盐胁迫反应中发挥作用的观点，并且BR信号是植物耐受盐的必要条件。我们的数据表明了ERAD成分调节植物生长和胁迫反应的可能机制。
Plants modify their growth and development to protect themselves from detrimental conditions by triggering a variety of signaling pathways, including the activation of the ubiquitin-mediated protein degradation pathway. Endoplasmic reticulum (ER)-associated protein degradation (ERAD) is an important aspect of the ubiquitin-proteasome system, but only a few of the active ERAD components have been reported in plants. Here, we report that the Arabidopsis thaliana ubiquitin-conjugating enzyme, UBC32, a stress-induced functional ubiquitin conjugation enzyme (E2) localized to the ER membrane, connects the ERAD process and brassinosteroid (BR)-mediated growth promotion and salt stress tolerance. In vivo data showed that UBC32 was a functional ERAD component that affected the stability of a known ERAD substrate, the barley (Hordeum vulgare) powdery mildew O (MLO) mutant MLO-12. UBC32 mutation caused the accumulation of bri1-5 and bri1-9, the mutant forms of the BR receptor, BRI1, and these mutant forms subsequently activated BR signal transduction. Further genetic and physiological data supported the contention that UBC32 plays a role in the BR-mediated salt stress response and that BR signaling is necessary for the plant to tolerate salt. Our data indicates a possible mechanism by which an ERAD component regulates the growth and stress response of plants.