HeLa cells (DSMZ) were grown in DMEM (Invitrogen) supplemented with 10% fetal calf serum (Biochrom), 1% HEPES (Invitrogen) and 1% penicillin/streptomycin (Invitrogen) at 37°C and 5% CO2. At ∼80% confluence, cells were transfected with the respective cDNAs using Fugene HD Transfection Reagent (Roche, Promega) following the supplier's directions. Opossum kidney cells (American Type Culture Collection) were grown in DMEM-F12 (Invitrogen) supplemented with 10% fetal calf serum (Biochrom) and 1% penicillin/streptomycin (Invitrogen). At ∼80% confluence, cells were transfected with the respective cDNAs using Lipofectamine 2000 (Invitrogen) following the supplier's directions. Brefeldin A (BFA; Sigma) and nocodazole (Sigma) were applied at 10 µg/ml and 10 µM, respectively.
