Chemically aggregated luciferase is efficiently reactivated by the human Hsp70 system including Hsp110 as NEF. (A) Luciferase levels in supernatants and pellets of native or chemically aggregated luciferase samples. Data shown represent the average of at least three experiments±s.e. (B) Reactivation of 20 nM luciferase from urea-induced aggregates was monitored upon addition of the human Hsp70-Hsp40 (2 μM Hsc70, 1 μM Hdj1) or Hsp70-Hsp40-Hsp110 system (Hsc70, Hdj1 and 0.2–0.4 μM Hsp105, Apg2 or Apg1). (C) Reactivation of chemically aggregated luciferase by the yeast Hsp70-Hsp40-NEF system (2 μM Ssa1, 1 μM Ydj1±0.1 μM Sse1 or 2 μM Snl1ΔN) or bichaperone system including the disaggregase Hsp104 (Ssa1, Ydj1, 1 μM Hsp104±Sse1). Reactivation data shown represent the average of at least three experiments±s.e.