Blue light activates the plasma membrane H+-ATPase by phosphorylation of the C-terminus in stomatal guard cells
Blue light activates the plasma membrane H+-ATPase by phosphorylation of the C-terminus in stomatal guard cells
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DOI：
10.1093/emboj/18.20.5548
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发表时间：
1999-10-15
期刊：
影响因子：
11.4
通讯作者：
Shimazaki, K
中科院分区：
文献类型：
--
作者：
Kinoshita, T;Shimazaki, K
蓝光（BL）诱导气孔开放，气孔开放是由保卫细胞中K+盐积累驱动的。BL激活H+泵;然而，BL的感知被转换成泵激活的机制仍然未知。我们提出的证据表明，泵是质膜H+-ATP酶和BL激活H+-ATP酶通过磷酸化。BL脉冲（30 s，100 μ mol/m2/s）以相似的时程增加了蚕豆保卫细胞原生质体质膜H+-ATPase和H+泵的ATP水解。BL可使H+-ATP酶可逆磷酸化，磷酸化程度与ATP水解活性成正比.保卫细胞H ~+-ATP酶的两种同工蛋白的丝氨酸和苏氨酸残基的磷酸化只发生在C端。用H+-ATP酶共沉淀14-3-3蛋白，重组14-3- 3蛋白与磷酸化的H+-ATP酶C端结合。这些结果表明，BL激活质膜H+-ATP酶通过磷酸化的C-末端的丝氨酸/苏氨酸蛋白激酶，和14-3-3蛋白在激活中具有关键作用。
The opening of stomata, which is driven by the accumulation of K+ salt in guard cells, is induced by blue light (BL). The BL activates the H+ pump; however, the mechanism by which the perception of BL is transduced into the pump activation remains unknown. We present evidence that the pump is the plasma membrane H+-ATPase and that BL activates the H+-ATPase via phosphorylation. A pulse of BL (30 s, 100 mu mol/m(2)/s) increased ATP hydrolysis by the plasma membrane H+-ATPase and H+ pumping in Vicia guard cell protoplasts with a similar time course. The H+-ATPase was phosphorylated reversibly by BL, and the phosphorylation levels paralleled the ATP hydrolytic activity. The phosphorylation occurred exclusively in the C-termini of H+-ATPases on both serine and threonine residues in two isoproteins of H+-ATPase in guard cells. An endogenous 14-3-3 protein was coprecipitated with H+-ATPase, and the recombinant 14-3-3 protein bound to the phosphorylated C-termini of H+-ATPases. These findings demonstrate that BL activates the plasma membrane H+-ATPase via phosphorylation of the C-terminus by a serine/threonine protein kinase, and that the 14-3-3 protein has a key role in the activation.