蛋白激酶PKS5通過阻斷質(zhì)膜H+-ATP酶與14-3-3蛋白的相互作用抑制其活性

關(guān) 鍵 詞：PKS5；質(zhì)膜質(zhì)子泵（PM H⁺-ATPase）；非損傷微測(cè)技術(shù)(MIFE)

參考文獻(xiàn)：Anja T.Fuglsang, et al. The Plant Cell, 2007, 19:1617-1634

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abstract:

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.