Differential activation of the rice sucrose nonfermenting1-related protein kinase2 family by hyperosmotic stress and abscisic acid
Differential activation of the rice sucrose nonfermenting1-related protein kinase2 family by hyperosmotic stress and abscisic acid
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DOI：
10.1105/tpc.019943
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发表时间：
2004-05-01
期刊：
影响因子：
11.6
通讯作者：
Hattori, T
中科院分区：
文献类型：
--
作者：
Kobayashi, Y;Yamamoto, S;Hattori, T
迄今为止，在数据库中发现了大量属于蔗糖非发酵1相关蛋白激酶2 （SnRK2）家族的蛋白激酶序列。然而，只有有限数量的家族成员被表征并涉及脱落酸（ABA）和高渗胁迫信号。我们鉴定了10个由水稻基因组编码的SnRK2蛋白激酶。10个成员均在培养的细胞原生质体中表达，并分析其调控作用。在这里，我们证明了所有的家族成员都被高渗胁迫激活，其中三个也被ABA激活。令人惊讶的是，没有只被ABA激活的成员。发现这种激活是通过磷酸化调节的。除了ABA调控方面的功能差异外，各成员之间的活化对高渗强度的依赖性也不同。我们表明，相对分散的c端结构域主要负责这种功能差异，尽管激酶结构域也有助于这些差异。结果表明，SnRK2蛋白激酶家族已经进化为专门用于高渗胁迫信号传导，并且个体成员已经获得了不同的调节特性，包括通过修改c端结构域对ABA的响应性。
To date, a large number of sequences of protein kinases that belong to the sucrose nonfermenting1-related protein kinase2 (SnRK2) family are found in databases. However, only limited numbers of the family members have been characterized and implicated in abscisic acid (ABA) and hyperosmotic stress signaling. We identified 10 SnRK2 protein kinases encoded by the rice (Oryza sativa) genome. Each of the 10 members was expressed in cultured cell protoplasts, and its regulation was analyzed. Here, we demonstrate that all family members are activated by hyperosmotic stress and that three of them are also activated by ABA. Surprisingly, there were no members that were activated only by ABA. The activation was found to be regulated via phosphorylation. In addition to the functional distinction with respect to ABA regulation, dependence of activation on the hyperosmotic strength was different among the members. We show that the relatively diverged C-terminal domain is mainly responsible for this functional distinction, although the kinase domain also contributes to these differences. The results indicated that the SnRK2 protein kinase family has evolved specifically for hyperosmotic stress signaling and that individual members have acquired distinct regulatory properties, including ABA responsiveness by modifying the C-terminal domain.