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.
Publication types
-
Research Support, N.I.H., Extramural
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
-
14-3-3 Proteins / metabolism*
-
Adaptation, Physiological / drug effects
-
Alleles
-
Amino Acid Sequence
-
Arabidopsis / cytology
-
Arabidopsis / drug effects
-
Arabidopsis / enzymology*
-
Arabidopsis / genetics
-
Arabidopsis Proteins / antagonists & inhibitors
-
Arabidopsis Proteins / chemistry
-
Arabidopsis Proteins / genetics
-
Arabidopsis Proteins / metabolism*
-
Calcium Signaling / drug effects
-
Cell Membrane / drug effects
-
Cell Membrane / enzymology*
-
DNA, Bacterial
-
Down-Regulation / drug effects
-
Ethyl Methanesulfonate
-
Gene Expression Regulation, Enzymologic / drug effects
-
Gene Expression Regulation, Plant / drug effects
-
Hydrogen-Ion Concentration
-
Membrane Potentials / drug effects
-
Molecular Sequence Data
-
Mutation / genetics
-
Phosphoserine / metabolism
-
Plant Growth Regulators / pharmacology
-
Plant Roots / drug effects
-
Plant Roots / metabolism
-
Protein Binding / drug effects
-
Protein Serine-Threonine Kinases / genetics
-
Protein Serine-Threonine Kinases / metabolism*
-
Proton-Translocating ATPases / antagonists & inhibitors*
-
Proton-Translocating ATPases / chemistry
-
Protons
-
RNA Interference
-
Saccharomyces cerevisiae / metabolism
Substances
-
14-3-3 Proteins
-
Arabidopsis Proteins
-
DNA, Bacterial
-
Plant Growth Regulators
-
Protons
-
T-DNA
-
Phosphoserine
-
Ethyl Methanesulfonate
-
At2g30360 protein, Arabidopsis
-
Protein Serine-Threonine Kinases
-
Proton-Translocating ATPases
-
AHA2 protein, Arabidopsis