The Arabidopsis chaperone J3 regulates the plasma membrane H+-ATPase through interaction with the PKS5 kinase.
The plasma membrane H(+)-ATPase (PM H(+)-ATPase) plays an important role in the regulation of ion and metabolite transport and is involved in physiological processes that include cell growth, intracellular pH, and stomatal regulation. PM H(+)-ATPase activity is controlled by many factors, including hormones, calcium, light, and environmental stresses like increased soil salinity. We have previously shown that the Arabidopsis thaliana Salt Overly Sensitive2-Like Protein Kinase5 (PKS5) negatively regulates the PM H(+)-ATPase. Here, we report that a chaperone, J3 (DnaJ homolog 3; heat shock protein 40-like), activates PM H(+)-ATPase activity by physically interacting with and repressing PKS5 kinase activity. Plants lacking J3 are hypersensitive to salt at high external pH and exhibit decreased PM H(+)-ATPase activity. J3 functions upstream of PKS5 as double mutants generated using j3-1 and several pks5 mutant alleles with altered kinase activity have levels of PM H(+)-ATPase activity and responses to salt at alkaline pH similar to their corresponding pks5 mutant. Taken together, our results demonstrate that regulation of PM H(+)-ATPase activity by J3 takes place via inactivation of the PKS5 kinase.
Yang
Yongqing
Y
College of Life Sciences, Peking University, Beijing 100871, China.
Qin
Yunxia
Y
Xie
Changgen
C
Zhao
Feiyi
F
Zhao
Jinfeng
J
Liu
Dafa
D
Chen
Shouyi
S
Fuglsang
Anja T
AT
Palmgren
Michael G
MG
Schumaker
Karen S
KS
Deng
Xing Wang
XW
Guo
Yan
Y
D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D009154:Mutation; D018517:Plant Roots / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism*; D018749:RNA, Plant / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology
D029681:Arabidopsis Proteins; D050956:HSP40 Heat-Shock Proteins; D017346:Protein Serine-Threonine Kinases; D006180:Proton-Translocating ATPases; D018749:RNA, Plant; D012965:Sodium Chloride; C523537:SIP4 protein, Arabidopsis