Fig. 4.

Effects of novel P-gp substrates on ATPase activity. The vanadate-sensitive activity of P-gp was determined as outlined in Materials and Methods. Basal P-gp ATPase activity was compared with activity in the presence of 0.1, 1, or 10 μM concentrations of the substrates (A) ispinesib, (B) KW-2478, (C) GSK-690693, (D) AT7519 or (E) gedatolisib. Verapamil (F) is shown as a positive control. Graphs depict average values from three independent experiments (error bars ± S.D.). Significance was determined by a one-way analysis of variance followed by a Dunnet test for multiple comparisons. Asterisks denote significant difference from the control, where P < 0.05 (*); P < 0.01 (**).