PLIC-1 and epidermal growth factor substrate 15 regulate aggresome formation. Lysates from human embryonic kidney 293 cells transfected with AUI-Q78 and (A) control or PLIC-1 RNAi duplexes or (B) control or EPS15 RNAi duplexes were western blotted with (A) PLIC-1 and (B) EPS15 antibodies. α-Tubulin (A,B) was used as a loading control. (C) Cells transfected as in (A,B) were immunostained with AUI antibodies and 20 random fields of view were quantified for the number of cells containing AUI-Q78 aggresomes. RNAi-transfected cells were normalized to control (arbitrarily assigned a value of 1) for each experiment±s.e.m. (n=3 or more), between-subject analysis of variance was carried out and significant differences from control were found (*P<0.05, **P<0.01) using the Tukey's honestly significant difference post hoc test. (D) Images of cells transfected as in (A,B) and immunostained with AUI antibodies. Fewer cells form aggresomes (arrows) on PLIC-1 and EPS15 knockdown. Also note the increase in cells with diffuse AUI-Q78 expression in these panels. Scale bar, 30 μm. EPS15, epidermal growth factor substrate 15; PLIC-1, protein linking IAP to the cytoskeleton; RNAi, RNA interference.