Abstract
Different input signals create their own characteristic Ca2+ fingerprints. These fingerprints are distinguished by frequency, amplitude, duration, and number of Ca2+ oscillations. Ca2+-binding proteins and protein kinases decode these complex Ca2+ fingerprints through conformational coupling and covalent modifications of proteins. This decoding of signals can lead to a physiological response with or without changes in gene expression. In plants, Ca2+-dependent protein kinases and Ca2+/calmodulin-dependent protein kinases are involved in decoding Ca2+ signals into phosphorylation signals. This review summarizes the elements of conformational coupling and molecular mechanisms of regulation of the two groups of protein kinases by Ca2+ and Ca2+/calmodulin in plants.
ACKNOWLEDGEMENTS
The authors gratefully acknowledge the support of NSF (grant MCB-0082256), NASA (grant NAG-10-0061), and USDA (grant 2002-00741).