Exogenous phosphoinositides are sufficient to recruit endogenous αCat. (A) Schematic of BODIPY-labeled phosphoinositide/histone H1 complex formation and integration into the apical membrane of polarized MDCK cells grown on filters for 2 wk. (B) Slice views of PI35P₂, PIP₂, or PIP₃ integrated via histone H1 complex into MDCK cells. Images were captured via confocal microscope using identical exposure time and laser intensity. Arrows indicate colocalization of αCat and phosphoinositide. Bar, 10 µm. (C) Colocalization was analyzed for each slice (0.2-µm steps) via Pearson’s correlation coefficient (chosen over Mander’s because it is independent of signal levels and background) in Nikon Elements (n = 3). (Left) Plotted value for each slice from apical (A) to basal (B) side. (Right) Plotted values represent all values calculated within a stack. Data are mean ± SD. Significance by one-way ANOVA with multiple comparisons: ****, P < 0.0001.