FIGURE 7.
The effects of [Pi] upon the phosphatase activities of PPIP5K1, PPIP5K2, and DIPP1. Phosphatase assays, performed as described under “Experimental Procedures,” contained 1 μm [3H]InsP8, either zero [Pi] (open circles) or 5 mm [Pi] (closed circles), and either 25 ng of PPIP5K1 (A and B), 40 ng of PPIP5K2 (C and D), or 33 ng of DIPP1 (E and F). Assays were quenched, neutralized, and then analyzed by HPLC (see “Experimental Procedures”); representative chromatographs are shown. Insets to B and D depict additional experiments (error bars represent S.E. from three biological replicates) in which the concentration of Pi was varied as shown.