Paradigms and Networks for Intracellular Calcium Signaling in Plant Cells

Abstract Calcium (Ca2+) is a ubiquitous second messenger in all eukaryotes. A challenging question is how the cation serves as a messenger for numerous signals and confers specificity to cellular responses. Recent studies have established a concept called “calcium signature” that specifies calcium changes triggered by each signal. Along with this concept comes the “decoding” of calcium signatures—how cells recognize and translate the signatures (codes) into the correct cellular responses. The initial step in the decoding process involves sensor proteins that bind calcium and change their conformation, leading to activation or inactivation of the downstream target molecules thereby regulating the specific biochemical and physiological processes. In this chapter, studies on the major groups of calcium sensors including calcium‐dependent protein kinases (CDPKs), calmodulin (CaM), and calcineurin B‐like proteins (CBLs) will be summarized and general paradigms and networks of calcium signaling processes will be discussed. I will particularly focus on the more recent studies that have advanced our understanding on calcium signal transduction in plants.