Fig. 3

Blocking TDP-43 SUMOylation at K408 impairs the cellular stress response in neurons. A Representative images and quantification of G3BP1 stress granule dynamics in mouse primary cortical neurons (7 DIV) during stress (1 h 250 μM sodium arsenite) and recovery. G3BP1 contrast was set for optimal visualization of stress granules. Scale bar = 25 μm (N = 5), 2-Way ANOVA with Fisher’s LSD test data presented as mean ± SEM, * p < 0.05, ** p < 0.005. B Representative western blot and quantification of RIPA and UREA fractions from mouse primary cortical neurons (7 DIV) during stress (1 h 250 μM sodium arsenite) and recovery. Quantification found in Fig. S6A. C Representative images and quantification of TDP-43 nuclear foci formation in mouse primary cortical neurons (7 DIV) during stress (1 h 250 μM sodium arsenite) and recovery. Cyan arrowheads denote cells with nuclear TDP-43 foci. Scale bar = 25 μm. (N = 5), 2-Way ANOVA with Fisher’s LSD test data presented as mean ± SEM, ** p < 0.005. D Representative images and quantification of G3BP1 stress granule dynamics in mouse primary cortical neurons (7 DIV) during repeated stress (30-min 250 μM sodium arsenite treatment) and recovery (30-min washout), repeated 3 times. Scale bar = 25 μm. (N = 3), 2-Way ANOVA with Fisher’s LSD test data presented as mean ± SEM, * p < 0.05, ** p < 0.005. E Representative images and quantification of TDP-43 nuclear foci formation in mouse primary cortical neurons (7 DIV) during repeated stress (30-min 250 μM sodium arsenite treatment) and recovery (30-min washout), repeated 3 times. Cyan arrowheads denote cells with nuclear TDP-43 foci. Scale bar = 25 μm. (N = 3), 2-Way ANOVA with Fisher’s LSD test data presented as mean ± SEM, ****p < 0.0001. For all immunofluorescent assays at least 50 cells were imaged and quantified per replicate (N = 3–5). All assays present wild type mice in grey and K408R/K408R mice in purple