Fig. 6. (A) Endocytosis rates in wild-type, mdrA1-/mdrA2- and rtoA-/mdrA1-/mdrA2- cells. Cells were collected and resuspended in HL5 containing FITC-dextran. At the times indicated by the symbols, cells were removed, washed twice in HL5 and once with wash buffer. They were then lysed in wash buffer containing Triton X-100 and the fluorescence measured as described in Materials and Methods. (B) Exocytosis rates in wild-type, mdrA1-/mdrA2- and rtoA-/mdrA1-/mdrA2- cells. Cells were allowed to internalize FITC dextran for 3 hours; they were then washed and resuspended in fresh HL5. At the times indicated by the symbols, cells were collected by centrifugation, washed once and lysed in wash buffer containing Triton X-100. The fluorescence was then measured as discussed in Materials and Methods. Values are mean±s.e.m. mdrA-, mdrA1-/mdrA2-; rtoA-/mdrA, rtoA-/mdrA1-/mdrA2-.
