FIGURE 6.

PT domain co-sediments with phospholipid vesicles containing PI(3,4,5)P₃. Purified PT domain (2.5 μm) was incubated with sucrose-loaded vesicles composed of the indicated lipids. Bound and free PT proteins were separated by sedimentation, and the fraction bound was determined as described under “Experimental Procedures.” The data, compiled from two independent experiments with separately prepared SLVs, were fitted to a nonlinear variable slope regression line using GraphPad Prism. The R² value for the fits were 0.99 for binding to vesicles containing PI(3,4,5)P₃, and 0.80 for binding to the vesicles lacking PI(3,4,5)P₃. Bars indicate ranges of two independent experiments.