Figure 4

Effect of various concentrations of RIC-3 on FRET efficiencies between α4CFP and β2YFP subunits and protein expression levels of α4CFP and β2YFP subunits. Equimolar amounts of α4CFP and β2YFP subunits were coexpressed with various concentrations of RIC-3. The ratio of RIC-3 to α4CFP β2YFP nAChR cDNAs was varied to 0:1 , 0.02:1, 0.1:1, 1:1, and 5:1. (A) Quantification of FRET efficiencies between α4CFP and β2YFP subunits showed no significant change over various concentrations of RIC-3 up to 1:1 concentration (p = 0.08, one-way ANOVA). (B) Quantification of mean α4CFP fluorescence per cell showed a significant progressive increase with rising concentrations of RIC-3 (p < 0.0001, Kruskal-Wallis rank sum test). (C) The mean β2YFP fluorescence intensity per cell showed a significant increase with increasing concentrations of RIC-3 (p < 0.0001, Kruskal-Wallis rank sum test). (B, C) However, high RIC-3 concentrations at 5:1 reduced both α4CFP and β2YFP fluorescence intensities closer to baseline values. Significant difference levels comparing groups of RIC-3 coexpressing cells relative to no RIC-3 controls: * p = 0.02, ** p = 0.002, *** p < 0.0001, NS p > 0.05, Wilcoxon rank sum test post-hoc pair wise analyses.