S-nitrosylation of phosphotransfer proteins represses cytokinin signaling
S-nitrosylation of phosphotransfer proteins represses cytokinin signaling
复制标题
磷酸转移蛋白的 S-亚硝基化抑制细胞分裂素信号传导
DOI：
10.1038/ncomms2541
复制
发表时间：
2013-02-01
影响因子：
16.6
通讯作者：
Zuo, Jianru
中科院分区：
文献类型：
--
作者：
Feng, Jian;Wang, Chun;Zuo, Jianru
细胞分裂素是植物生长和发育中必需的植物激素。在拟南芥中，细胞分裂素信号传导是由磷酸中继介导的，该磷酸中继依次将磷酰基从细胞分裂素受体转移到组氨酸磷酸转移蛋白（AHP）和反应调节剂（ARR）。然而，人们对磷继电器的调控机制知之甚少。在这里，我们发现一氧化氮通过 S-亚硝基化抑制磷酸中继活性，从而负向调节细胞分裂素信号传导。AHP1 在 Cys 115 处的 S-亚硝基化抑制其磷酸化以及随后磷酰基转移至 ARR1。 AHP1 的不可亚硝基化突变使突变蛋白对一氧化氮不敏感，抑制其磷酸化，并部分缓解一氧化氮对细胞分裂素反应的抑制作用。相反，AHP1 的亚硝基体突变会导致 AHP1 和 ARR1 的磷酸化降低，从而导致细胞分裂素反应受损。这些发现说明了氧化还原信号和细胞分裂素信号协调植物生长和发育的机制。
Cytokinin is an essential phytohormone in plant growth and development. InArabidopsis, cytokinin signalling is mediated by a phosphorelay that sequentially transfers phosphoryl groups from the cytokinin receptors to histidine phosphotransfer proteins (AHPs) and response regulators (ARRs). However, little is known about the regulatory mechanism of the phosphorelay. Here, we show that nitric oxide negatively regulates cytokinin signalling by inhibiting the phosphorelay activity throughS-nitrosylation.S-nitrosylation of AHP1 at Cys 115 represses its phosphorylation and subsequent transfer of the phosphoryl group to ARR1. A non-nitrosylatable mutation of AHP1 renders the mutant protein insensitive to nitric oxide in repressing its phosphorylation, and partially relieves the inhibitory effect of nitric oxide on the cytokinin response. Conversely, a nitrosomimetic mutation of AHP1 causes reduced phosphorylation of AHP1 and ARR1, thereby resulting in a compromised cytokinin response. These findings illustrate a mechanism by which redox signalling and cytokinin signalling coordinate plant growth and development.