Endocytotic sucrose uptake in Amoeba proteus induced with the calcium ionophore A23187

The calcium ionophore A23187 brings about an influx of calcium and uptake of sucrose by endocytosis in Amoeba proteus. The amount of endocytotic sucrose uptake elicited by the ionophore depends upon the external calcium ion concentration. Calcium ion movements may serve to couple the surface phase of endocytosis with cytoplasmic uptake of the endocytotic inducer.