Knockdown of MYPT1 was achieved by transfecting HeLa cells with MYPT1 specific siRNAs (Silencer® select Product # s9237, s9235). Western blot analysis (Fig. a) was performed using whole cell extracts from the MYPT1 knockdown cells (lane 3), non-specific scrambled siRNA transfected cells (lane 2) and untransfected cells (lane 1). The blots were probed with Anti-MYPT1 Polyclonal Antibody (Product # PA5-17164, 1:1000 dilution) and Goat anti-Rabbit IgG (H+L) Superclonal™ Secondary Antibody, HRP conjugate (Product # A27036, 0.25 µg/mL, 1:4000 dilution). Densitometric analysis of this western blot is shown in histogram (Fig. b). Decrease in signal upon siRNA mediated knock down confirms that antibody is specific to MYPT1.