SV channels dominate the vacuolar Ca²⁺ release during intracellular signaling

Vacuoles have long been suggested to mediate a rise in the cytosolic free Ca²⁺ during environmental signal transduction. This study addresses the issue of the control of vacuolar calcium release by some of the known signaling molecules such as IP₃, cADPR, ABA, ATP, cAMP, cGMP, H₂O₂ and CaM. Over 30 concentrations and/or combinations of these signaling compounds were studied in a series of electrophysiological experiments involving non-invasive ion flux measurements (the MIFE) and patch-clamp techniques. Our results suggest that calcium, calmodulin and nucleotides cause calcium release via SV channels.