The CBL–CIPK Ca 2+ ‐decoding signaling network: function and perspectives

Summary Calcium serves as a versatile messenger in many adaptation and developmental processes in plants. Cellular calcium signals are detected and transmitted by calcium‐binding proteins functioning as sensor molecules. The family of calcineurin B‐like (CBL) proteins represents a unique group of calcium sensors and contributes to the decoding of calcium transients by interacting with and regulating the family of CBL‐interacting protein kinases (CIPKs). In higher plants, CBL proteins and CIPKs form a complex signaling network that allows for flexible but specific signal–response coupling during environmental adaptation reactions. This review presents novel findings concerning the evolution of this signaling network and key insights into the physiological function of CBL–CIPK complexes. These aspects will be presented and discussed in the context of emerging functional principles governing efficient and specific information processing in this signaling system. Contents Summary 517 I. Introduction 517 II. Comparative genomics of the CBL–CIPK signaling network 518 III. Structural features and functional principles of CBLs and CIPKs 521 IV. Functions and targets of CBL–CIPK complexes 523 V. Conclusions and perspectives 525 Acknowledgements 526 References 526