Ca2+ signals are transient, hence, upon a stimulus-induced increase in cytosolic Ca2+ concentration, cells have to re-establish 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.

Ca2+-dependent phosporegulation of the plasma membrane Ca2+-ATPase ACA8 modulates Stimulus-induced Ca2+ signatures / A. Costa, L. Luoni, C. Marrano, K. Hashimoto, P. Köster, S. Giacometti, M. De Michelis, J. Kudla, M.C. Bonza. - In: JOURNAL OF EXPERIMENTAL BOTANY. - ISSN 1460-2431. - (2017 May 20). [Epub ahead of print] [10.1093/jxb/erx162]

Ca2+-dependent phosporegulation of the plasma membrane Ca2+-ATPase ACA8 modulates Stimulus-induced Ca2+ signatures

A. Costa;L. Luoni;C. Marrano;S. Giacometti;M. De Michelis;M.C. Bonza
2017-05-20

Abstract

Ca2+ signals are transient, hence, upon a stimulus-induced increase in cytosolic Ca2+ concentration, cells have to re-establish 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.
Arabidopsis thaliana; calcineurin B-like protein; Ca2+ signature; CBL-interacting protein kinases; plasma membrane Ca2+-ATPase; phosphorylation
Settore BIO/04 - Fisiologia Vegetale
20-mag-2017
JOURNAL OF EXPERIMENTAL BOTANY
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/498495
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