Figure 1. Silencing of LRPPRC leads to an imbalance between mitochondria-encoded and nuclear-encoded subunits of complex IV and triggers UPRmt. SH-SY5Y cells were treated with control or LRPPRC siRNA for three days and transferred for 24 hours to low glucose medium (5 mM) to enhance oxidative phosphorylation. (A) Total protein extracts were analyzed by Western using anti-LRPPRC, anti-COX I, anti-COX IV and anti-β-Actin antibodies. COX IV/COX I ratios are indicated. (B) The same protein extracts as in panel A were also analyzed by Western using anti-LRPPRC, anti-HSP70, anti-HSP60, anti-ClpP and anti-β-Actin antibodies. Ratios relative to the control siRNA are indicated. (For all panels, quantifications are based on data from three independent experiments; average values are shown and error bars indicate s.d.; *p ≤ 0.05, ***p ≤ 0.001 by one way ANOVA for panel A and one sample t-test for panel B).