Figure 5. Chaperones are involved in Cdc19 amyloid disassembly.

(A) – (B) Inhibition of Hsp104 activity delays Cdc19 and SG re-solubilization. Cells of the indicated genotype were treated with 5 mM Gdn-HCl for 3 hours prior to a 30 min heat shock at 42 °C. (A) Aggregate disassembly after stress release was monitored by fluorescence microscopy. Representative images, arrowheads indicate Cdc19 aggregates (n = 3 independent experiments). Scale bar: 5 μm. (B) Cdc19 aggregate disassembly was quantified by counting the number of foci at different time points after stress. The average time ± S.E.M. to reach a 50% reduction in foci number is displayed (n = 3 independent experiments, >30 cells per sample per experiment, two-tailed t-test, P_WT = 0.0268, P_irrev+tps1Δ = 0.048).

(C) – (D) Overexpression of Hsp104 partially rescues growth of cdc19^irrev cells after heat shock. (C) Serial dilutions of exponentially growing cells of the indicated genotype were spotted on agar plates before or after a 30 min heat shock of 42 °C, and imaged after 3 days at 30 °C (n = 3 independent experiments). Where indicated, overexpression of Hsp104 was induced by treating cells with 10 mM estradiol for 3 hours. (D) Growth restart was also quantified by measuring cell density (OD₆₀₀) over time after inoculation of equal cell numbers at 30 °C. Mean cell density 22 hours after stress release ± S.E.M. is shown (n = 3 independent experiments, two-tailed t-test, P_{irrev-irrev+tps1Δ} = 0.0000413, P_{irrev+tps1Δ - irrev+tps1Δ+Hsp104OE} = 0.0055). Source data for all graphical representations can be found in Source Data Fig. 5.