AtRAE1 is involved in degradation of ABA receptor RCAR1 and negatively regulates ABA signalling in Arabidopsis

作者：Li, Dekuan; Zhang, Liang; Li, Xiaoyi; Kong, Xiangge; Wang, Xiaoyu; Li, Ying; Liu, Zhibin; Wang, Jianmei; Li, Xufeng; Yang, Yi^*

来源：Plant, Cell and Environment, 2018, 41(1): 231-244.

DOI：10.1111/pce.13086

• ABA signalling
• AtRAE1
• CUL4-DDB1 E3 ligase
• RCAR1
• ubiquitination

The phytohormone abscisic acid (ABA) plays an important role in regulating plant growth, development, and adaption to various environmental stresses. Regulatory components of ABA receptors (RCARs, also known as PYR/PYLs) sense ABA and initiate ABA signalling through inhibiting the activities of protein phosphatase 2C in Arabidopsis. However, the way in which ABA receptors are regulated is not well known. A DWD protein AtRAE1 (for RNA export factor 1 in Arabidopsis), which may act as a substrate receptor of CUL4-DDB1 E3 ligase, is an interacting partner of RCAR1/PYL9. The physical interaction between RCAR1 and AtRAE1 is confirmed in vitro and in vivo. Overexpression of AtRAE1 in Arabidopsis causes reduced sensitivity of plants to ABA, whereas suppression of AtRAE1 causes increased sensitivity to ABA. Analysis of protein stability demonstrates that RCAR1 is ubiquitinated and degraded in plant cells and AtRAE1 regulates the degradation speed of RCAR1. Our findings indicate that AtRAE1 likely participates in ABA signalling through regulating the degradation of ABA receptor RCAR1.
Recent studies have established the relationship between E3 ligases and several ABA receptor RCARs. The ubiquitin ligase DDA1, RIFP1, and RSL1 have been demonstrated to target RCAR3 and RCAR10 to modulate ABA signalling, respectively. Due to 14 members of RCAR family, however, the degradation of the other RCARs is still unknown. In this study, we confirm the significance of a novel E3 ligase AtRAE1 involved in ABA signalling by regulating ABA receptor RCAR1's stability.

• 出版日期2018-1
• 单位四川大学