Fig. 6. Inhibition of laminin-1-induced GM1 clustering with lyso-GM1. (A) DRG cells were treated with 2.5 µM lyso-GM1 or 2.5 µM lyso-LacCer, labeled with BODIPY-GM1 and immunostained with Alexa-Fluor-546-conjugated anti-TrkA antibody or with Alexa-Fluor-546-conjugated anti-β1 integrin antibody. Cells were then analyzed by confocal laser microscopy 5 minutes after the addition of 5 µg/ml of laminin-1. Arrowheads indicate clustering and colocalization of BODIPY-GM1 with TrkA or β1 integrin. Bar, 5 µm. (B) DRG cells were treated with 2.5 µM lyso-GM1 or 2.5 µM lyso-LacCer and incubated with 5 µg/ml of laminin-1 for 24 hours in the presence of 50 ng/ml NGF. Cells were stained with antibodies against the neurofilament proteins and with Hoechst dye 33258. Bar, 100 µm. Bar graph shows the mean length + s.d. of neurite outgrowth from 30 DRG cells. (^*P<0.001; two-sided t-test).