Arabidopsis protein kinase PKS5 inhibits the plasma membrane H+-ATPase by preventing interaction with 14-3-3 protein
Arabidopsis protein kinase PKS5 inhibits the plasma membrane H+-ATPase by preventing interaction with 14-3-3 protein
复制标题
DOI：
10.1105/tpc.105.035626
复制
发表时间：
2007-05-01
期刊：
影响因子：
11.6
通讯作者：
Zhu, Jian-Kang
中科院分区：
文献类型：
--
作者：
Fuglsang, Anja T.;Guo, Yan;Zhu, Jian-Kang
跨质膜 pH 梯度的调节是植物对多种激素和环境信号（包括生长素、蓝光和真菌诱导子）反应的重要组成部分。然而，人们对介导这种调节的信号成分知之甚少。在此，我们报道拟南芥 Ser/Thr 蛋白激酶 PKS5 是质膜质子泵 (PM H+-ATPase) 的负调节因子。由于质子被挤出到细胞外空间，功能丧失的 pks5 突变体植物更能耐受高外部 pH 值。 PKS5 在 C 端调节域的新位点 Ser-931 处磷酸化 PM H+-ATPase AHA2。该位点的磷酸化可抑制酵母表达系统中 PM H+-ATP 酶与激活 14-3-3 蛋白之间的相互作用。我们发现 PKS5 与钙结合蛋白 SCaBP1 相互作用，并且高外部 pH 值可以引发胞质游离钙浓度的增加。这些结果表明 PKS5 是介导 PM H+-ATPase 调节的钙信号通路的一部分。
Regulation of the trans-plasma membrane pH gradient is an important part of plant responses to several hormonal and environmental cues, including auxin, blue light, and fungal elicitors. However, little is known about the signaling components that mediate this regulation. Here, we report that an Arabidopsis thaliana Ser/Thr protein kinase, PKS5, is a negative regulator of the plasma membrane proton pump (PM H+-ATPase). Loss-of-function pks5 mutant plants are more tolerant of high external pH due to extrusion of protons to the extracellular space. PKS5 phosphorylates the PM H+-ATPase AHA2 at a novel site, Ser-931, in the C-terminal regulatory domain. Phosphorylation at this site inhibits interaction between the PM H+-ATPase and an activating 14-3-3 protein in a yeast expression system. We show that PKS5 interacts with the calcium binding protein SCaBP1 and that high external pH can trigger an increase in the concentration of cytosolic-free calcium. These results suggest that PKS5 is part of a calcium-signaling pathway mediating PM H+-ATPase regulation.