Fig. 5

UDCA stimulates the VAPB-PTPIP51 interaction. (a) Characterisation of VAPB-PTPIP51 NanoBiT assays. SH-SY5Y cells were transfected with either empty Small and Large BiT plasmids (SBiT + LBiT), SBiT + LBiT-VAPB, SBiT + LBiT-PTPIP51, LBiT + SBiT-VAPB, LBiT + PTPIP51-SBiT, SBiT-VAPB + PTPIP51-LBiT or LBiT-VAPB + PTPIP51-SBiT as indicated. Signals above background were only detected in cells transfected with SBiT-VAPB + PTPIP51-LBiT or LBiT-VAPB + PTPIP51-SBiT and the highest signals were detected in SBiT-VAPB + PTPIP51-LBiT cells. Data were analysed by one-way ANOVA with Tukey’s post hoc test. Data are from 3 independent experiments each with N = 6; error bars are SEM. * p≤0.05, *** p≤0.001 (b) UDCA stimulates VAPB-PTPIP51 binding in NanoBiT assays. SH-SY5Y cells were transfected with SBiT-VAPB + PTPIP51-LBiT and then treated with vehicle or increasing concentrations of UDCA for 24 h. 62.5 µM and 125 µM UDCA both stimulated VAPB-PTPIP51 binding. Data were analysed by one-way ANOVA with Tukey’s post hoc test. Data are from 4 independent experiments each with N = 6. Error bars are SEM. *** p≤0.001, ns not significant. (c) UDCA stimulates VAPB-PTPIP51 binding in cortical neurons. Representative images of VAPB-PTPIP51 PLA signals in neurons treated with vehicle or 62.5 µM UDCA for 24 h. Cells were immunostained for MAP2 (artificially shown in cyan) to confirm neuronal identity Scale bars = 5 μm. Data were analysed by unpaired t-test. N = 45 cells from 3 independent experiments. Error bars are SEM, *** p≤0.001, ns not significant