FIGURE 4.

Isoprenoid shortage causes deficiency in autophagy. A, in HEK293 LC3-GFP cells, the lack of isoprenoids causes a clear reduction in the number of autophagosomes. This is almost completely dependent GGPP because the addition of exogenous GGPP can rescue the phenotype. Representative pictures are shown; the bar graph shows the averages of three experiments. B, in THP-1 cells, the defect appears not to be in the induction of autophagy because no differences are observed in LC3 levels. The bar graph contains quantification of shown blot, normalized first to loading control, and then the untreated condition is set to 1; the values are representative of four independent experiments. C, there is a late stage block in autophagy, as seen by the lack of p62 degradation upon simvastatin treatment. The bar graph contains quantification of shown blot, treated as in B, representative of four independent experiments shown. D, the defect in autophagy is not mediated by mtROS. The p62 levels after treatment with scavenger MitoQ or control compound TPP could not rescue the phenotype of the statin treatment. Protein levels in TPP conditions are lower because the concentration of TPP used approaches toxic levels. The bar graphs contains quantification of shown blot, normalized as in B, representative of two independent experiments shown.