Fig. 4.

Incubation in starvation medium affects the sizes of lysosomes in lvsB mutant cells. Wild-type, apm3, and lvsB cells were incubated in HL5 or StM for 4 h and processed for immunofluorescence to detect p80 and H⁺-ATPase. (A) Pictures of lvsB cells grown in rich medium (HL5) or starved in StM are shown. In lvsB cells, the sizes of lysosomes (p80 positive and H⁺-ATPase-positive; arrowheads) increased significantly upon starvation. In a fraction of starved cells, a single giant lysosome filled most of the cell (lower panel). Postlysosomes (p80 positive and H⁺-ATPase negative; arrows) and contractile vacuole (p80 negative and H⁺-ATPase positive; pinheads) are also indicated. Scale bar, 5 μm. (B) The sizes of lysosomes in cells grown in rich medium (HL5) or starved in StM were measured. The diameters of lysosomes were identical in wild-type (WT) and apm3 mutant cells, whereas starved lvsB cells exhibited bigger lysosomes.