Fig. 5
From: Insights into degradation mechanism of N-end rule substrates by p62/SQSTM1 autophagy adapter
Oligomeric states of p62 are controlled by pH. a Binding affinity measurements using FITC-labeled R-BiP peptide against increasing concentrations of p62 constructs (MBP-PB1-ZZ WT—blue line, MBP-PB1-ZZ K7A—red line, MBP-PB1-ZZ D69A—green line, GST-ZZ—violet line, and Flag-ZZ—wine line) at pH 6.0. The error bars represent standard error of the mean (S.E.M.) of more than three independent experiments. b The SEC-MALS results with MBP-PB1-ZZ WT (red line) and mutants K7A (green line) and D69A (sky blue line) at pH 6.0. The horizontal line represents the measured molar mass. Each species is indicated by an arrow with experimental (SEC-MALS) molar mass. WT protein adopted huge polymeric states whereas the K7A and D69A mutants adopted mainly monomeric states with minor dimeric species as shown in Fig. 2b. c The SEC-MALS result with MBP-PB1-ZZ WT at physiological pH 7.4 (orange line) and acidic pH 4.5 (blue line). The horizontal lines represent the measured molar mass, which approximated a decamer at pH 7.4 and trimer at pH 4.5. d Kratky plot of SAXS experiment to verify folding of p62 at pH 4.5
