Aggregase function of Hsp42 deletion mutants. (A) MDH was denatured for 60 min at 41°C in the absence or presence of Hsp42 WT and deletion mutants at the indicated ratios. As a control, Hsp42 proteins were heated alone. The formation of MDH aggregates was followed by turbidity measurements. (B) Complexes of MDH with Hsp42 WT or Hsp42ΔIDD formed at 41°C at equimolar ratios were analyzed by light microscopy. MDH aggregated at 47°C served as reference. As control, MDH and Hsp42 proteins were heated alone. Widefield images are presented. Bars, 5 µm.