NIH 3T3 cells (murine embryonic fibroblasts) and HAb2 cells (NIH
3T3 cells stably expressing HA [25]) were cultured as exponentially
growing subconfluent monolayers on 90-mm plates in DMEM
supplemented with Glutamax (Invitrogen) and 10% (v/v) fetal bovine
serum. Exponentially growing cells were dissociated with trypsin
(Invitrogen). The cells (2.5 × 105
) were plated and cultured overnight
on 30-mm plates in the presence of 2.5 mM sodium butyrate to
potentiate expression of HA [26,27]. In some experiments, we used
human erythrocyte ghosts labeled with fluorescent lipid PKH26
(Sigma, St. Louis, MO) and an aqueous dye, 6-carboxyfluorescein
(Invitrogen, Carlsbad, CA), prepared for experiments as described in
[22].