Figure 4.

PPFIA1-siRNA Reduces KIT Phosphorylation Level as Detected by Phospho-Array Assay

(A) Experimental design to detect the phosphorylative signal proteins in K562 cells transfected with PPFIA1-siRNA or miR-181a mimics. (B and C) Phosphorylative signal proteins in K562 cells transfected with PPFIA1-siRNA (B) and miR-181a mimic (C) were comprehensively investigated using an antibody microarray system compared with control. The phosphorylation ratio (Phos Ratio) was used as the modulation difference of phosphorylation sites between two samples and was computed as follows: phosphorylation ratio = phospho value/non-phosphorylated value. (D) The phosphor-fluorescent and unphospho-fluorescent images of KIT Tyr721, P38 MAPK Tyr182, and VEGFR2 Tyr951 sites. (E) Overexpression of PPFIA1 increased the expression of phosphorylated KIT, Akt, and ERK1/2 proteins in K562 cells. (F) Transfection of PPFIA1-siRNA for 48 h attenuated the expression of phosphorylated KIT, Akt, and ERK1/2 proteins in K562 cells. The data were presented as the mean ± SD obtained from at least three independent experiments.