AP180 null cells develop large contractile vacuoles in water. Wild-type cells (Ax2), clathrin light-null cells (CLC null), and AP180 null cells are shown in HL-5 media (Media, top row) and 20 min after shifting cells to water (bottom row). Contractile vacuoles are indicated with arrows. Scale bar, 10 μm. See accompanying videos, Supplementary Movies 3 and 4.