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Small Heat Shock Proteins Potentiate Amyloid Dissolution by Protein Disaggregases from Yeast and Humans

Figure 2

Hsp26 and Hsp42 synergize to inhibit spontaneous Sup35 prionogenesis.

(A, B) NM (5 µM) was incubated at 25°C with agitation for 6 h in the presence of increasing concentrations of BSA, Hsp26, Hsp42, or Hsp26 and Hsp42 (0–5 µM). For the mixture of Hsp26 and Hsp42, a 1∶1 ratio was employed. Thus, a concentration of 2 µM on the x-axis reflects 1 µM Hsp26 and 1 µM Hsp42. Fibrillization was measured by Thioflavin-T (ThT) fluorescence (A) or by determining the amount of SDS-resistant NM (B). Values represent means±SD (n = 3). (C) NM (5 µM) was assembled at 25°C with agitation for 6 h in the absence or presence of Hsp26 (0.6 µM or 3 µM), Hsp42 (0.6 µM or 3 µM), or Hsp26 and Hsp42 (0.3 µM or 1.5 µM of each). Reaction products were concentrated and transformed into [psi] cells. No NM and soluble NM served as negative controls. The proportion of [PSI+] colonies was then determined. Values represent means±SD (n = 3). (D) Sup35 (5 µM) was incubated at 25°C with agitation for 6 h in the presence of increasing concentrations of BSA, Hsp26, Hsp42, or Hsp26 and Hsp42 (0–5 µM). For the mixture of Hsp26 and Hsp42, a 1∶1 ratio was employed. Thus, a concentration of 2 µM on the x-axis reflects 1 µM Hsp26 and 1 µM Hsp42. Fibrillization was measured by ThT fluorescence. Values represent means±SD (n = 3).

Figure 2

doi: https://doi.org/10.1371/journal.pbio.1001346.g002