Evolution of acidic Ca²⁺ stores and their resident Ca²⁺-permeable channels

Acidic Ca(2+) stores refer to a collection of H(+)- and Ca(2+)-rich organelles involved in Ca(2+) signalling across taxonomic kingdoms. They include lysosomes, lysosome-related organelles, secretory vesicles, vacuoles and acidocalcisomes. Acidic Ca(2+) stores express several types of Ca(2+)-permeable channels belonging to the TRP, TPC, P2X and IP3/ryanodine receptor families. The channels have distinct phylogenomic profiles, and each acidic Ca(2+) store possesses a distinct Ca(2+) channel portfolio. The functions of acidic Ca(2+) stores appear to be conserved in processes such as signalling, membrane traffic and "auto-secretion". Thus, despite substantial variation in form, acidic Ca(2+) stores may function similarly across the natural world.