Calcium Homeostasis and Its Evolution.- Evolution of EF-Hand Proteins.- Calmodulin Target Recognition: Common Mechanism and Structural Diversity.- Calcium-Binding EGF-like Domains.- Calmodulin-Dependent Protein Kinases.- Structure of Calcineurin and Its Complex with Immunophilins.- The Ca2+ Pump of Sarcoplasmic and Endoplasmic Reticulum Membranes.- The Plasma Membrane Ca2+ ATPase.- The Na+/Ca2+ Exchanger: Structural Aspects, Function and Regulation.