期刊
GENES & DEVELOPMENT
卷 21, 期 16, 页码 2100-2111出版社
COLD SPRING HARBOR LAB PRESS, PUBLICATIONS DEPT
DOI: 10.1101/gad.1568207
关键词
light signaling; protein interaction; ubiquitination; proteasomal degradation; MG132
资金
- NIGMS NIH HHS [R56 GM044640-17, R56 GM044640, R01 GM044640, GM44640] Funding Source: Medline
Several positive regulators of phytochrome A signaling-e. g., LAF1, HFR1, and HY5-operate downstream from the photoreceptor, but their relative sites of action in the transduction pathway are unknown. Here, we show that HFR1RNAi/laf1 or hfr1-201/LAF1RNAi generated by RNA interference (RNAi) has an additive phenotype under FR light compared with the single mutants, hfr1-201 or laf1. This result indicates that LAF1 and HFR1 function in largely independent pathways. LAF1, an R2R3-MYB factor, interacts with HFR1, a basic helix-loop-helix ( bHLH) factor, and this interaction is abolished by the R97A mutation in the LAF1 R2R3 domain. Polyubiquitinations of LAF1 and HFR1 by the COP1 E3 ligase in vitro are inhibited by LAF1/HFR1 association. Consistent with this result, endogenous HFR1 is less stable in laf1 compared with wild type, and similarly, LAF1-3HA expressed from a transgene is also less stable in hfr1-201 than wild type. In transgenic plants, HFR1 levels are significantly elevated upon induced expression of LAF1 but not LAF1( R97A). Moreover, induced expression of LAF1 but not LAF1( R97A) delays post-translational HFR1 degradation in FR light. Constitutive coexpression of HFR1 and LAF1 but not HFR1 and LAF1 ( R97A) confers FR hypersensitivity in double transgenic plants. Our results show that in addition to their independent functions in phyA signaling, LAF1 and HFR1 also cooperate post-translationally to stabilize each other through inhibition of ubiquitination by COP1, thereby enhancing phyA photoresponses.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据