Fig. 6. Effect of Stx1-B subunit on the distribution of - and -tubulins in ACHN cells. ACHN cells were examined as described in Fig. 2 using Alexa-488-labeled anti--tubulin Ab (left panels, green) and Alexa-546-labeled anti--tubulin mAb (center panels, red). The arrowheads indicate the accumulation of -tubulin at the microtubule-organizing centers. Results are representative of three independent experiments.