Figure 9.

Chlorpromazine (CPZ) induces transfer of aqueous dye (CF) from RBCs to hemifused Ser HA-expressing cells. For each condition the ratio of COS7 cells stained with CF to those labeled by R18 was determined. In control experiments, after fusion was triggered by incubation for 2 min in a pH 5.0 solution at 37°C, and then incubated in PBS (supplemented with 20 mM raffinose) for 5 min at RT, virtually all WT HA-expressing cells (WT, first bar) were stained with both an aqueous dye (CF) and a membrane dye (R18). In contrast, CF spread into Ser HA-expressing cells was rarely observed, despite efficient R18 redistribution (second bar). These cells were exposed for 1 min at RT to either 0.05 mM (third bar) or 0.4 mM (fourth bar) CPZ, and then the CPZ-containing solution was replaced by PBS with raffinose. Error bars show the SE for 4–16 independent experiments.