Phosphorylation of Serine 186 of bHLH Transcription Factor SPEECHLESS Promotes Stomatal Development in Arabidopsis
Phosphorylation of Serine 186 of bHLH Transcription Factor SPEECHLESS Promotes Stomatal Development in Arabidopsis
复制标题
bHLH 转录因子 SPEECHLESS 丝氨酸 186 磷酸化促进拟南芥气孔发育
DOI：
10.1016/j.molp.2014.12.014
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发表时间：
2015
期刊：
影响因子：
27.5
通讯作者：
Jie Le
中科院分区：
文献类型：
--
作者：
Ke-Zhen Yang;Min Jiang;Ming Wang;Shan Xue;Ling-Ling Zhu;Hong-Zhe Wang;Jun-Jie Zou;Eun-Kyoung Lee;Fred Sack;Jie Le
气孔谱系的启动和随后的不对称分裂需要碱性螺旋-环-螺旋转录因子SPEECH LESS（SPCH）的活性。已经表明，SPCH作为有丝分裂原激活蛋白激酶（MAPK）级联或GSK 3样激酶油菜甾醇不敏感2（BIN 2）的底物控制进入气孔谱系。在这里，我们发现，SPCH的三个丝氨酸残基似乎是细胞周期蛋白依赖性激酶A;1（CDKA;1）在体外的主要磷酸化目标，其中丝氨酸186在气孔形成中起着至关重要的作用。一个SPCH构建体的表达包含一个突变，导致磷酸化缺陷的丝氨酸186残基未能挽救气孔缺陷的突变体。磷酸化模拟突变体SPCHS 186 D的表达弥补了显性负CDKA靶向表达的转基因株系中气孔产生缺陷;1.N146。因此，除了MAPK和BIN 2介导的SPCH磷酸化外，丝氨酸186的磷酸化是SPCH调节气孔发育功能所必需的。
The initiation of stomatal lineage and subsequent asymmetric divisions inArabidopsisrequire the activity of the basic helix-loop-helix transcription factor SPEECHLESS (SPCH). It has been shown that SPCH controls entry into the stomatal lineage as a substrate either of the MITOGEN-ACTIVATED PROTEIN KINASE (MAPK) cascade or GSK3-like kinase BRASSINOSTEROID INSENSITIVE 2 (BIN2). Here we show that three serine residues of SPCH appear to be the primary phosphorylation targets of Cyclin-Dependent Kinases A;1 (CDKA;1)in vitro, and among them Serine 186 plays a crucial role in stomatal formation. Expression of anSPCHconstruct harboring a mutation that results in phosphorylation deficiencies on Serine 186 residue failed to rescue stomatal defects inspchnull mutants. Expression of a phosphorylation-mimic mutantSPCHS186Dcomplemented stomatal production defects in the transgenic lines harboring the targeted expression of dominant-negativeCDKA;1.N146. Therefore, in addition to MAPK- and BIN2-mediated phosphorylation on SPCH, phosphorylation at Serine 186 is positively required for SPCH function in regulating stomatal development.