Fig. 5: β-Catenin and p120 are not needed to cluster E-cadherin through αABD.

a Schematic representation of the E-cadherin-α-catenin chimera, EcΔ-GFP-α506C805/871, which consists of an intact N-terminal portion of E-cadherin (its ectodomain and transmembrane domains) fused through GFP with a C-terminal portion of α-catenin starting from M3 subdomain. Another chimera, c/t-EcΔ-GFP-α506C805/871, is the same as above but incorporates point mutations (listed on the bottom) inactivating all known inter-ectodomain interactions: one cis and two trans, strand swapped and X dimerization. b Projections of all x-y optical slices of αCatKO-A431 cells expressing EcΔ-GFP-α506C805/871 stained for GFP (GFP, green) and for F-actin (actin, red). Only green channel is shown for low magnification. Bar, 10 µm. The dashed box area is zoomed on the bottom and shown as separate staining. Note that the chimera forms AJs associated with the actin cytoskeleton. Bar, 10 µm. c Western blot probed for GFP of cells shown in (b) and collected from control culture (Ctrl) and from cross-linked cultures in standard media (XL-HighCa) or in low calcium media for 3 h (XL-LowCa). d Projections of all x-y slices of c/t-EcΔ-GFP-α506C805/871 cells stained for GFP (GFP, green) and for F-actin (actin, red). Only green channel is shown for low magnification. Bar, 10 µm. The dashed boxed areas are presented in both colors. Projections of five optical z slices encompassing the apical membrane marked by yellow box (#1) are zoomed on the right. Only a single optical slice passing through a ventral cell membrane (marked by a white box, #2) is shown on the bottom. Bars, 10 µm. Note that the apical ruffles, invadopodia-like structures (Inp), and cell-cell contacting protrusions (Prtr) are especially enriched with the chimera. e The line scan performed along the dashed line shown in (d). Note that no specific actin enrichment is observed in places rich for the chimera clusters. f Western blot probed for GFP of cells expressing EcΔ-GFP-α506C805/871 (Ec506) and its adhesion-incompetent mutant (c/t-Ec506), which were obtained from control cultures (Ctrl) and after cross-linking (XL).