Volume 22, No 12, Dec 2012

ISSN: 1001-0602 
EISSN: 1748-7838 2018 
impact factor 17.848* 
(Clarivate Analytics, 2019)

Volume 22 Issue 12, December 2012: 1650-1655

ORIGINAL ARTICLES

Tonoplast calcium sensors CBL2 and CBL3 control plant growth and ion homeostasis through regulating V-ATPase activity in Arabidopsis

Ren-Jie Tang^1,2, Hua Liu¹, Yang Yang¹, Lei Yang^1,3, Xiao-Shu Gao¹, Veder J Garcia², Sheng Luan^2,3 and Hong-Xia Zhang¹

¹National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
²Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
³Plant Molecular Biology Institute, School of Life Sciences, Nanjing University, Nanjing 210093, China Correspondence: Sheng Luan, Hong-Xia Zhang,(sluan@berkeley.edu; hxzhang@sippe.ac.cn)

Plant responses to developmental and environmental cues are often mediated by calcium (Ca²⁺) signals that are transmitted by diverse calcium sensors. The calcineurin B-like (CBL) protein family represents calcium sensors that decode calcium signals through specific interactions with a group of CBL-interacting protein kinases. We report functional analysis of Arabidopsis CBL2 and CBL3, two closely related CBL members that are localized to the vacuolar membrane through the N-terminal tonoplast-targeting sequence. While cbl2 or cbl3 single mutant did not show any phenotypic difference from the wild type, the cbl2 cbl3 double mutant was stunted with leaf tip necrosis, underdeveloped roots, shorter siliques and fewer seeds. These defects were reminiscent of those in the vha-a2 vha-a3 double mutant deficient in vacuolar H⁺-ATPase (V-ATPase). Indeed, the V-ATPase activity was reduced in the cbl2 cbl3 double mutant, connecting tonoplast CBL-type calcium sensors to the regulation of V-ATPase. Furthermore, cbl2 cbl3 double mutant was compromised in ionic tolerance and micronutrient accumulation, consistent with the defect in V-ATPase activity that has been shown to function in ion compartmentalization. Our results suggest that calcium sensors CBL2 and CBL3 serve as molecular links between calcium signaling and V-ATPase, a central regulator of intracellular ion homeostasis.

Cell Research (2012) 22:1650-1665. doi:10.1038/cr.2012.161; published online 27 November 2012

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