Fig. 5.

PTP-PEST is required for adherens junction assembly. A: Ca²⁺ switch assay in C4- and SH4-transfected KM12C cells shows that adherens junction assembly is impaired in the absence of PTP-PEST expression as assessed by immunofluorescence staining for E-cadherin. Representative areas are shown at right, with arrows showing regions where junctional assembly is decreased in SH4 relative to C4 cells 2 h following Ca²⁺ switch, and dotted lines indicating the cell-cell boundary region analyzed (n = 20). Scale bar = 20 μm. B: quantitation of junctional intensity using line scan as described in materials and methods. The data are an average of 20 junctional boundaries in three separate fields analyzed for each condition. Pixel intensity of E-cadherin is decreased by 2.5-fold in SH4 cells relative to C4 cells following Ca²⁺ switch, 2 h following Ca²⁺ recovery, indicating impaired adherens junction assembly. C: total expression of E-cadherin and β-catenin are unaffected by Ca²⁺ switch. Tubulin is shown as a loading control.