(G) Quantification of CTxB retrograde transport in BMMs following siRNA-mediated depletion of Stx6 (siStx6) after AlexaFluor™488-CTxB binding on ice followed by 30 min incubation at 37˚C. Data are means ± SD from n=3 independent experiments, in which 100 cells were analyzed per experiment. The asterisk indicates a statistically significant difference (P=0.0114, unpaired Student's t test) compared to the siNT control. 