FIGURE 8.

Effect of PfI3 and PfI3W45 on PfPP1 phosphatase activity. Recombinant PfPP1 at 71 nm (A) or at 143 nm (B) was preincubated for 30 min at 37 °C with different concentrations of PfI3 or PfI3W45A before the addition of pNPP. ○ represents the relative phosphatase activity in the presence of different concentrations of recombinant His₆-tagged PfI3. ● represents the relative phosphatase activity in the presence of different concentrations of recombinant His₆-tagged PfI3W45A. C, inhibition of PfPP1 phosphatase activity by human Inhibitor-3 and Ypi1. PfPP1 at 122 nm was preincubated for 10 min with different amounts of GST-Inh3 (♦) or GST-Ypi1(■) before the addition of pNPP. Results presented as % of relative increase or decrease are means ± S.E. for three independent experiments performed in duplicate.