... as a result of the decrease in pH wasassayed by measuring the radioactivity of tritium, as described inMaterials and methods (In the figure, the y-axis represents the cpm values of pellet). ... Ca2+channel in the ER, whichincreases Ca2+leakage via a mechanism dependent onboth the pH and the C-terminal cytosolic region of the protein [9]. However, the precise role of BI-1 remainsunknown. ... InsP3receptor, we investigated the effect of externalCa2+on the PICR. External Ca2+consistently inhib-ited the PICR, regardless of the pH value outside the liposomes, when the Ca2+concentration...