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Arabidopsis protein kinase PKS5 inhibits the plasma membrane H+-ATPase by preventing interaction with 14-3-3 protein

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Fuglsang, AT and Schumaker, KS and Palmgren, MG and Zhu, JK and Guo, Y and Cuin, TA and Qui, Q and Song, C and Kristiansen, KA and Bych, K and Schulz, A and Shabala, SN (2007) Arabidopsis protein kinase PKS5 inhibits the plasma membrane H+-ATPase by preventing interaction with 14-3-3 protein. The Plant Cell, 19. pp. 1617-1634. ISSN 1040-4651

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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.

Item Type: Article
Journal or Publication Title: The Plant Cell
Publisher: American Society of Plant Biologists
Page Range: pp. 1617-1634
ISSN: 1040-4651
Identification Number - DOI: 10.1105/tpc.105.035626
Date Deposited: 07 Apr 2008 14:26
Last Modified: 18 Nov 2014 03:34
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