Fig. 9. Silencing of SNX5 and SNX6 leads to a decrease of global SNX1 levels. (A) Whereas suppression of SNX5 or SNX6 both impair SNX1 levels, their double knock-down almost completely eliminates SNX1 in HeLa cells. (B) To confirm that this effect was not due to off-targeting effects by SNX5 or SNX6 siRNA, RT-PCR was performed and SNX1 mRNA levels were compared with control cells that had been transfected with a scrambled siRNA. No difference in SNX1 mRNA was found between the control and SNX5 or SNX6 knock-down cells, suggesting that the reduction of SNX1 level is a post-transcriptional phenomenon, most probably due to the degradation of SNX1 in the absence of SNX5 and SNX6. ß-actin was used as a loading control for western blots; GAPDH was used as a control in RT-PCR.