Advances and current challenges in calcium signaling

Abstract

Content Summary414I.Introduction415II.Ca2+ importer and exporter in plants415III.The Ca2+ decoding toolkit in plants415IV.Mechanisms of Ca2+ signal decoding417V.Immediate Ca2+ signaling in the regulation of ion transport418VI.Ca2+ signal integration into long‐term ABA responses419VIIIntegration of Ca2+ and hormone signaling through dynamic complex modulation of the CCaMK/CYCLOPS complex420VIIICa2+ signaling in mitochondria and chloroplasts422IXA view beyond recent advances in Ca2+ imaging423XModeling approaches in Ca2+ signaling424XIConclusions: Ca2+ signaling a still young blooming field of plant research424Acknowledgements425ORCID425References425 Summary Temporally and spatially defined changes in Ca2+ concentration in distinct compartments of cells represent a universal information code in plants. Recently, it has become evident that Ca2+ signals not only govern intracellular regulation but also appear to contribute to long distance or even organismic signal propagation and physiological response regulation. Ca2+ signals are shaped by an intimate interplay of channels and transporters, and during past years important contributing individual components have been identified and characterized. Ca2+ signals are translated by an elaborate toolkit of Ca2+‐binding proteins, many of which function as Ca2+ sensors, into defined downstream responses. Intriguing progress has been achieved in identifying specific modules that interconnect Ca2+ decoding proteins and protein kinases with downstream target effectors, and in characterizing molecular details of these processes. In this review, we reflect on recent major advances in our understanding of Ca2+ signaling and cover emerging concepts and existing open questions that should be informative also for scientists that are currently entering this field of ever‐increasing breath and impact.

Calcium signals in guard cells enhance the efficiency by which abscisic acid triggers stomatal closure

“…2d). The Ca 2+ -dependent response is likely to be provoked by Ca 2+ -dependent protein kinases (CPKs; Harper et al, 1991;Geiger et al, 2010Geiger et al, , 2011Brandt et al, 2015) and calcineurin Blike (CBL)-interacting protein kinases (CIPKs) that bind to CBL proteins (Maierhofer et al, 2014;Kudla et al, 2018). Studies with CPK loss-of-function mutants support the function of these protein kinases in ABA-induced stomatal closure.…”

Plant immunity in signal integration between biotic and abiotic stress responses

“…Biotic/abiotic stresses commonly involve protein phosphorylation cascades via RLKs, receptor‐like cytoplasmic kinases, Ca 2+ ‐dependent protein kinases and MAPKs in intracellular signaling (Kudla et al ., ; Liang & Zhou, ; M. Zhang et al ., ), but it remains poorly understood how their synergistic or antagonistic interactions are established and coordinated to fine‐tune the overall signaling networks. Here, we discuss recent advances in immune and cold MAPK signaling through the hallmark MPK3/MPK6 and MPK4 cascades (Fig.…”

The battle of two ions: Ca2+ signalling against Na+ stress

“…ten different CBL-type Ca 2+ sensors and 26 CBL-interacting kinases (CIPKs) in Arabidopsis (Kolukisaoglu et al 2004;Weinl & Kudla 2009). Many studies have established the function of distinct CBL-CIPK complexes in a wide range of biological processes including abiotic stress responses, ion homeostasis, pathogen responses and plant development (Kudla et al 2018). Quite remarkably, phylogenetic analysis of this signalling system suggested that Ca 2+ -dependent regulation of Na + homeostasis represents the evolutionary most ancient function of this signalling network (Edel & Kudla 2015).…”