The organelles that accumulated LDL in the presence of 1 lM
ONO are reminiscent of LEs. To determine if the LDL-containing
compartments are in fact LEs, cells were transfected to express
Rab7-GFP, a LE marker [16]. After transfection (48 h), cells were pulse-labeled with LDL-DiI for 5 min at 37 C, and then chased
for 40 min with 1 lM ONO. The results showed that in the presence
of 1 lM ONO, LDL accumulated in centrally located compartments
that are positive for Rab7 (Fig. 4I and J). Thus, 1 lM ONO
allows transport of LDL to, but not out of, LEs.