The plant Ca2+-ATPases repertoire : biochemical features and physiological functions

Ca2+ ATPases are P-type ATPases which use the energy of ATP hydrolysis to pump Ca2+ from the cytoplasm into intracellular compartments or into the apoplast. Plant cells possess two types of Ca2+ pumping ATPases, named respectively ECAs (for ER-type Ca2+ ATPase) and ACAs (for auto-inhibited Ca2+ ATPase). Each type comprehends different isoforms, localised on different membranes. Here we summarise the available knowledge of the biochemical characteristics and of the physiological role of plant Ca2+ ATPases, greatly improved after gene identification which allows both biochemical analysis of single isoforms through heterologous expression in yeast and expression profiling and phenotypic analysis of single isoform knock-out mutants.