Arabidopsis protein kinase PKS5 inhibits the plasma membrane H+ -ATPase by preventing interaction with 14-3-3 protein.
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.
Fuglsang
Anja T
AT
Department of Plant Biology, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
Guo
Yan
Y
Cuin
Tracey A
TA
Qiu
Quansheng
Q
Song
Chunpeng
C
Kristiansen
Kim A
KA
Bych
Katrine
K
Schulz
Alexander
A
Shabala
Sergey
S
Schumaker
Karen S
KS
Palmgren
Michael G
MG
Zhu
Jian-Kang
JK
D048948:14-3-3 Proteins / Q000378:metabolism*; D000222:Adaptation, Physiological / Q000187:drug effects; D000483:Alleles; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D004269:DNA, Bacterial; D015536:Down-Regulation / Q000187:drug effects; D005020:Ethyl Methanesulfonate; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010768:Phosphoserine / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors* / Q000737:chemistry; D011522:Protons; D034622:RNA Interference; D012441:Saccharomyces cerevisiae / Q000378:metabolism
D048948:14-3-3 Proteins; D029681:Arabidopsis Proteins; D004269:DNA, Bacterial; D005020:Ethyl Methanesulfonate; D010768:Phosphoserine; D010937:Plant Growth Regulators; D017346:Protein Serine-Threonine Kinases; D006180:Proton-Translocating ATPases; D011522:Protons; C036483:T-DNA; C523537:SIP4 protein, Arabidopsis; C479903:AHA2 protein, Arabidopsis