Fig. 4: Tardigrade sHSPs can chaperone against heat-induced protein aggregation.
From: Tardigrade small heat shock proteins can limit desiccation-induced protein aggregation
a HSP21 and HSP24.6 limit heat-induced aggregation of citrate synthase at 43 °C. Aggregation is plotted as the change in A340 relative to that of 5 µM citrate synthase alone at 2 h. Datapoints from four biological replicates are shown along with a fitted line and 95% confidence interval. b) Heterologous expression of HSP24.6 improved heat shock survival of BL21 E. coli (p = 0.02, Dunnett’s test, n = 4). c HSP21 and HSP24.6 limited heat-induced aggregation of the water soluble BL21 E. coli proteome. In vitro aggregation of soluble protein following 1 h at 52 °C was significantly different across conditions shown (p < 0.001, 1-way ANOVA, n = 3–4). HSP21 (p = 0.01, Dunnett’s test, n = 4) and HSP24.6 (p < 0.001, Dunnett’s test, n = 4) reduced aggregation, while BSA (p = 0.96, n = 3, Dunnett’s test) did not have an effect. sHSPs or BSA were added at a 1:1 mass ratio with E. coli protein. d) Soluble (supernatant, S) and insoluble (pellet, P) protein fractions were assessed by SDS-PAGE. A representative Coomassie-stained gel shows soluble and insoluble protein following heat shock at 52 °C for 1 h. The pelleted insoluble fraction was concentrated 4× before loading. *p < 0.05, ***p < 0.001.
