AKIN10 and FUSCA3 interact to control lateral organ development and phase transitions in Arabidopsis.
AKIN10 and FUSCA3 interact to control lateral organ development and phase transitions in Arabidopsis.
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DOI：
10.1111/j.1365-313x.2011.04832.x
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发表时间：
2012-03
期刊：
影响因子：
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通讯作者：
A. Tsai;Sonia Gazzarrini
中科院分区：
文献类型：
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作者：
A. Tsai;Sonia Gazzarrini
在真核生物中，SNF1(蔗糖非发酵-1)/AMPK(AMP激活的蛋白激酶)/SnRK1(SnF1-Related Protein Kinase 1)是能量状态的感受器。尽管这些激酶在调节细胞对代谢应激的反应中起着重要的作用，但只有少数SnRK1底物被鉴定出来。通过酵母双杂交筛选，我们分离到AKIN10作为B3结构域转录因子FUSCA3(FUS3)的相互作用因子，FUS3是拟南芥种子成熟的重要调节因子。下拉和双分子荧光互补(BIFC)分析分别证实了体外和植物中的相互作用。凝胶内激酶分析表明，AKIN10使FUS3磷酸化，并且FUS3的N-末端结构域是AKIN10磷酸化所必需的。FUS3 N-末端部分SnRK1共有序列中3个丝氨酸(S55A/S56A/S57A)的突变显著降低了AKIN10对FUS3的磷酸化，表明这些丝氨酸是AKIN10的主要靶点。在无细胞系统中，AKIN10正向调节FUS3的稳定性，因为AKIN10的过表达延缓了重组FUS3的降解。过量表达AKIN10的植物表现出种子萌发、营养生长和开花时间的延迟，这表明AKIN10拮抗了胚胎到营养和营养到生殖的转变。此外，AKIN10的过表达改变了子叶、角果和花器官的发育，表明AKIN10调控侧向器官的发育。遗传交互作用研究表明，Fus3-3突变部分挽救了AKIN10过表达导致的相变和器官发育缺陷。综上所述，这些发现表明，FUS3和AKIN10在调节拟南芥发育相变和器官发生方面存在物理上的相互作用，并共享重叠的途径。
The Snf1 (sucrose non-fermenting-1)/AMPK (AMP-activated protein kinase)/SnRK1 (Snf1-related protein kinase 1) kinases act as sensors of energy status in eukaryotes. Despite the important role of these kinases in regulation of cellular responses to metabolic stress, only a few SnRK1 substrates have been identified. Using yeast two-hybrid screens, we isolated AKIN10 as an interactor of the B3-domain transcription factor FUSCA3 (FUS3), an essential regulator of seed maturation in Arabidopsis. Pull-down and bi-molecular fluorescence complementation (BiFC) assays confirm the interaction in vitro and in planta, respectively. In-gel kinase assays show that AKIN10 phosphorylates FUS3 and that the N-terminal domain of FUS3 is required for AKIN10 phosphorylation. Mutations of three serines (fus3(S55A/S56A/S57A) ) within a partial SnRK1 consensus sequence in the N-terminal region of FUS3 reduce greatly FUS3 phosphorylation by AKIN10, which indicates that these serines are the predominant AKIN10 target sites. In a cell-free system, AKIN10 positively regulates FUS3 stability, as overexpression of AKIN10 delayed the degradation of the recombinant FUS3. Plants over-expressing AKIN10 show delayed seed germination, vegetative growth and flowering time, indicating that AKIN10 antagonizes the embryonic-to-vegetative and vegetative-to-reproductive phase transitions. Furthermore, overexpression of AKIN10 alters cotyledon, silique and floral organ development, suggesting that AKIN10 regulates lateral organ development. Genetic interaction studies show that the fus3-3 mutation partially rescues the phase transition and organ development defects caused by AKIN10 overexpression. Taken together, these findings indicate that FUS3 and AKIN10 interact physically and share overlapping pathways to regulate developmental phase transitions and organogenesis in Arabidopsis.