Baz binds E-cad and is required for normal junctional levels of mobile E-cad. (A) E-cad and Baz colocalize at junctions as scored by antibody staining of endogenous proteins. (B) Endogenous E-cad and α-catenin (α-cat), but not EB1-GFP, coimmunoprecipitate with Baz. Input lane shows 5% of immunoprecipitation volume. (C–F) Baz (C; black/green, anti-Baz) and E-cad (D; black/green, anti–E-cad) in wild-type cells and adjacent cells expressing baz-RNAi (magenta) or CD8 as control (not depicted), and quantitation of levels (E and F). Bars, 5 µm. (G–J) E-cad–GFP FRAP in cells expressing baz-RNAi at DV (G and H) and AP borders (I and J). Examples of recovery are shown in G and I, with red circles on the prebleached frame (P) showing the bleach spots, and averaged recovery curves (error bars indicate mean ± SEM) with best fit curves shown as solid lines in H and J. See Fig. S1 for a similar experiment with β-catenin RNAi. (K) Combining the data permits an estimate of mobile and immobile E-cad pools (error bars indicate mean ± SEM) at DV and AP borders. ***, P < 0.0001.