Required for cytokinesis, contractile vacuole function and development. In starved cells it binds transiently and in a calcium-dependent manner to the plasma membrane and intracellular vacuoles. In some cells, the transient membrane localization is observed to occur multiple times in an oscillatory manner over several minutes. Also found to be associated to the plasma membrane, contractile vacuoles, organelles of the endolysosomal pathway and phagosomes. Expressed at relatively high levels in vegetative cells. The expression goes down at the 2th hour of development and increase slightly up to the 8th hour, it then goes down until the 12th hour where it increase gain to reach a maximal value at the 16th hour. Cells exhibit normal growth rates and a slight cytokinesis defect. When placed in starvation conditions these cells appear to aggregate into mounds and form fingers with normal timing; however, they are delayed or arrested in the finger stage. When placed in water the cells forme unusually large contractile vacuoles, indicating a defect in contractile vacuole function. Belongs to the copine family.