Figure 4. PP2Ac mediates EIF4E regulation by AURKA inRAD001 resistant cells.
A)Western blot analysis indicated higher p-PP2Ac (Y307) protein levels, indicative of inhibition of phosphatase activity, in the FLO-1 (A) and SK-GT-4 (E) resistant cells than their respective parental cells. The PP2A activity assay confirmed that both FLO-1 and SK-GT-4 resistant cells displayed a significant reduction in the PP2A activity (B &F). Alisertibor AURKA knockdown enhanced PP2A activity in FLO-1 RAD-R (C1) (C & D) and SK-GT-4 RAD-R (G & H) cells. Dual knockdown of AURKA and PP2Ac in FLO-1 parental and RAD-R (C1) (I) and SK-GT-4 parental and RAD-R (pool) (J) indicated that PP2A mediates AURKA regulation of EIF4E. AURKA immunoprecipitation and Western blot analysis in FLO-1 Parental and FLO-1 RAD-R (C1) cells (K) and SK-GT-4 Parental and SK-GT-4 RAD-R (Pool) cells (L) indicated a protein interaction between AURKA and PP2Ac.