Fig. 2. RabD^Q67L expression results in the formation of large vacuolar structures. Ax4 cells were transformed with a plasmid containing the HA-tagged rabD constitutively active mutant cDNA driven by an inducible promoter that is turned off in the presence of folate or turned on in the absence of folate. The level of RabD expression was analyzed by western blot using anti-RabD antibodies (inset). The top panel indicates that the growth rate for wild-type and mutant cells are identical. Bar, 3 µm.