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Ca2+-dependent phosphoregulation of the plasma membrane Ca2+-ATPase ACA8 modulates stimulus-induced calcium signatures.

Authors :
Luoni, Laura
Marrano, Claudia Adriana
Giacometti, Sonia
Bonza, Maria Cristina
Costa, Alex
De Michelis, Maria Ida
Jörg Kudla
Kenji Hashimoto
Philipp Köster
Source :
Journal of Experimental Botany. 6/1/2017, Vol. 68 Issue 12, p3215-3230. 16p.
Publication Year :
2017

Abstract

Ca2+ signals are transient, hence, upon a stimulus-induced increase in cytosolic Ca2+ concentration, cells have to reestablish resting Ca2+ levels. Ca2+ extrusion is operated by a wealth of transporters, such as Ca2+ pumps and Ca2+/H+ antiporters, which often require a rise in Ca2+ concentration to be activated. Here, we report a regulatory fine-tuning mechanism of the Arabidopsis thaliana plasma membrane-localized Ca2+-ATPase isoform ACA8 that is mediated by calcineurin B-like protein (CBL) and CBL-interacting protein kinase (CIPK) complexes. We show that two CIPKs (CIPK9 and CIPK14) are able to interact with ACA8 in vivo and phosphorylate it in vitro. Transient co-overexpression of ACA8 with CIPK9 and the plasma membrane Ca2+ sensor CBL1 in tobacco leaf cells influences nuclear Ca2+ dynamics, specifically reducing the height of the second peak of the wound-induced Ca2+ transient. Stimulus-induced Ca2+ transients in mature leaves and seedlings of an aca8 T-DNA insertion line exhibit altered dynamics when compared with the wild type. Altogether our results identify ACA8 as a prominent in vivo regulator of cellular Ca2+ dynamics and reveal the existence of a Ca2+-dependent CBL-CIPK-mediated regulatory feedback mechanism, which crucially functions in the termination of Ca2+ signals. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00220957
Volume :
68
Issue :
12
Database :
Academic Search Index
Journal :
Journal of Experimental Botany
Publication Type :
Academic Journal
Accession number :
124600613
Full Text :
https://doi.org/10.1093/jxb/erx162