Figure 2.

Double-label immunofluorescence microscopy of monolayer cultures of epithelial cells derived from human multilayered (A, keratinocytes of line HaCaT; B, squamous cell carcinoma-derived line A-431) or one-layered (C, D: liver carcinoma cells of line PLC) tissues. Two forms of attachment of bundles of keratin IFs (green, mouse monoclonal antibody mAb lu-5) to the plaques of desmosomes (A, B: red, desmoplakin, guinea pig antibodies) represent a continuous transcellular cytoskeletal system (the chromatin in the nuclei of A, C, and D is stained blue with DAPI reagent): The cells in A are connected by cell-to-cell bridges with near-centrally located desmosomes, whereas in B the bodies of the cells are directly and tightly associated with each other via numerous, closely spaced desmosomes. In contrast, no specific anchorage of keratin IF bundles is seen at cell junctions of the zonula or punctum adherens type, which are seen by immunoreaction for β-catenin (C, red, guinea pig antibodies) or protein p0071 (D, red, murine mAb). Bars: 20 µm.