TOUSLED Is a Nuclear Serine/Threonine Protein Kinase That Requires a Coiled-coil Region for Oligomerization and Catalytic Activity*
TOUSLED Is a Nuclear Serine/Threonine Protein Kinase That Requires a Coiled-coil Region for Oligomerization and Catalytic Activity*
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DOI：
10.1074/jbc.272.9.5838
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发表时间：
1997-02
期刊：
影响因子：
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通讯作者：
J. Roe;T. Durfee;John R. Zupan;P. Repetti;B. McLean;P. Zambryski
中科院分区：
文献类型：
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作者：
J. Roe;T. Durfee;John R. Zupan;P. Repetti;B. McLean;P. Zambryski
TOUSLED（TSL）基因是拟南芥叶和花的正常形态发生所必需的。蛋白质序列分析预测TSL由一个羧基端蛋白激酶催化结构域和一个大的氨基端调节结构域组成。TSL融合蛋白，表达和纯化从酵母中，用于证明TSL蛋白激酶活性在体外。TSL在丝氨酸和苏氨酸残基上反式自磷酸化，并磷酸化外源底物。利用酵母双杂交系统，发现TSL通过其NH 2-末端结构域寡聚化。缺失序列表明，包含两个α-螺旋片段的区域参与卷曲螺旋结构是寡聚化的关键。TSL通过一个必需的NH 2-末端核定位信号定位到植物细胞的核中;然而，该信号对于蛋白激酶活性不是必需的。最后，缺失突变体表现出催化活性和寡聚化能力之间的严格相关性，认为蛋白激酶的激活需要TSL分子之间的相互作用。
The TOUSLED (TSL) gene is essential for the proper morphogenesis of leaves and flowers in Arabidopsis thaliana. Protein sequence analysis predicts TSL is composed of a carboxyl-terminal protein kinase catalytic domain and a large amino-terminal regulatory domain. TSL fusion proteins, expressed in and purified from yeast, were used to demonstrate TSL protein kinase activity in vitro. TSL trans-autophosphorylates on serine and threonine residues, and phosphorylates exogenous substrates. Using the yeast two-hybrid system, TSL was found to oligomerize via its NH2-terminal domain. A deletion series indicates that a region containing two α-helical segments predicted to participate in a coiled-coil structure is essential for oligomerization. TSL localizes to the nucleus in plant cells through an essential NH2-terminal nuclear localization signal; however, this signal is not necessary for protein kinase activity. Finally, deletion mutants demonstrate a strict correlation between catalytic activity and the ability to oligomerize, arguing that activation of the protein kinase requires interaction between TSL molecules.