Shaping the calcium signature

Summary In numerous plant signal transduction pathways, Ca 2+ is a versatile second messenger which controls the activation of many downstream actions in response to various stimuli. There is strong evidence to indicate that information encoded within these stimulus‐induced Ca 2+ oscillations can provide signalling specificity. Such Ca 2+ signals, or ‘Ca 2+ signatures’, are generated in the cytosol, and in noncytosolic locations including the nucleus and chloroplast, through the coordinated action of Ca 2+ influx and efflux pathways. An increased understanding of the functions and regulation of these various Ca 2+ transporters has improved our appreciation of the role these transporters play in specifically shaping the Ca 2+ signatures. Here we review the evidence which indicates that Ca 2+ channel, Ca 2+ ‐ATPase and Ca 2+ exchanger isoforms can indeed modulate specific Ca 2+ signatures in response to an individual signal. Contents Summary 275 I. Introduction 276 II. Ca 2+ signalling pathways 276 III. Shaping Ca 2+ signatures 278 IV. Ca 2+ influx channels 278 V. Ca 2+ influx channels as modulators of Ca 2+ signatures 281 VI. Ca 2+ efflux transporters 282 VII. Ca 2+ efflux transporters as modulators of Ca 2+ signatures 284 VIII. The shaping of noncytosolic Ca 2+ signatures 285 IX. Future insights into the role of Ca 2+ oscillators from modelling studies 287 X. Conclusions and perspectives 288 Acknowledgements 288 References 288