FIG. 6.

There is no direct interaction between TDH and sphingomyelin. (A to D) Liposomes including sphingomyelin and cholesterol were incubated with TDH or lysenin for 30 min at room temperature, and the toxin-liposome mixtures were added to HeLa cells or erythrocytes. (A and B) HeLa cells were incubated with liposomes and 1 μg/ml lysenin for 3 h (A) or 20 μg/ml TDH for 3 h (B). (C and D) Erythrocytes were exposed to liposomes and 500 ng/ml lysenin for 30 min (C) or 10 μg/ml TDH for 30 min (D). Data are shown as means and SD from three independent experiments. *, P < 0.01. (E) Binding of TDH or lysenin to sphingomyelin. Spotting of sphingomyelin (0, 10, and 50 nmol) onto the TLC plates was followed by lipid overlay assays.