Fig. 1

ER dynamic movements are disturbed in growth cones of Smn-deficient motoneurons. a Representative time-lapse images of growth cone filopodia from cultured Smn+/+;SMN2tgtg (control) and Smn−/−;SMN2tgtg motoneurons expressing mCherry-ER. Arrows indicate movements of ER in filopodia. b Quantitative Image Correlation Spectroscopy analysis of ER dynamics in growth cone filopodia shows reduced ER movements in Smn−/−;SMN2tgtg motoneurons, compared to control (****P < 0.0001; n = 41 cells from 6 independent experiments). CytoD-treatment results in reduced filopodia ER dynamics in Smn+/+;SMN2tgtg compared to DMSO-treated Smn+/+;SMN2tgtg neurons (****P < 0.0001). ER movements were also reduced in filopodia of CytoD-treated Smn−/−;SMN2tgtg compared to DMSO-treated Smn−/−;SMN2tgtg neurons (n.s., P = 0.0628; n = 22–41 cells from 3 independent experiments). c Representative time-lapse images of growth cone core from cultured Smn+/+;SMN2tgtg and Smn−/−;SMN2tgtg motoneurons expressing mCherry-ER. d Quantification of ER dynamics shows reduced ER movements in the core of Smn−/−;SMN2tgtg growth cones compared to control (***P = 0.0009; n = 40–44 cells from 6 independent experiments). ER movements are reduced in the growth cone core of CytoD-treated Smn+/+;SMN2tgtg compared to DMSO-treated Smn+/+;SMN2tgtg neurons (****P < 0.0001; n = 24–44 cells). CytoD treatment also reduces ER movements in the core of Smn−/−;SMN2tgtg growth cones (*P = 0.0235; n = 18–40 cells from 3 independent experiments). All data are normalized to Smn+/+;SMN2tgtg control. Data are presented in scatter dot plot; error bars represent mean ± SEM. Statistical analyses were done by Two-way ANOVA with Tukey multiple comparison post-hoc test