The Arabidopsis Chaperone J3 Regulates the Plasma Membrane H⁺-ATPase through Interaction with the PKS5 Kinase

Publication Type:Journal Article
Year of Publication:2010
Authors:Yang, Y, QIN, YUNXIA, Xie, C, Zhao, F, Zhao, J, Liu, D, Chen, S, Fuglsang, AT, Palmgren, MG, Schumaker, KS, Deng, XWang, Guo, Y
Journal:The Plant Cell
Date Published:2010
ISBN Number:10404651

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.

Short Title:The Plant Cell
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