Fig. 6. Dp staining is altered in PKP1-deficient epidermis and also in PKP1-deficient keratinocytes following a low Ca²⁺ switch. (A) Examples of 5 µm thickness skin sections from normal epidermis (top panels) and PKP1-deficient epidermis (bottom panels) stained with antibodies against plakoglobin (PG5.1, left panels) and Dp (11-5F, right panels). Plakoglobin staining is unaltered in PKP1-deficient epidermis (bottom left) compared with normal epidermis (top left), while Dp displays a more diffuse, intercellular staining pattern in PKP1 epidermis (bottom right, arrow) compared to normal control (top right). (B) Confocal microscopy imaging of Dp (11-5F, green) and desmoglein (AHP321, red) staining of a region of suprabasal normal breast epidermis (upper panels) and a region of suprabasal PKP1-deficient epidermis (lower panels). Right column displays merged images. Normal epidermis shows diffuse and linear staining for both Dp and desmogleins (upper left and upper middle) while PKP1-deficient epidermis shows linear cell membrane staining for desmogleins (lower middle) but Dp staining shows wide, peripheral membrane staining (lower left, arrow). (C) Double staining of nullpB cells (upper panels) and nullPKP cells (lower panels), cultured for 72 hours in high Ca²⁺ medium and switched to low Ca²⁺ medium for 1 hour, for Dp (11-5F, left panels) and desmoglein 3 (AHP319, right panels). The majority of Dp staining is non-membrane localised in nullpB cells (upper left panel, arrow indicates cell-cell junction with reduced Dp reactivity), while the majority of desmoglein 3 staining is membrane bound (upper right panel). Areas of membrane-bound desmoglein 3 but not Dp were readily identified. In nullPKP cells the majority of Dp staining is membrane localised (lower left panel), while the majority of desmoglein 3 is also membrane bound (lower right panel). Scale bars: 100 µm (A); 10 µm (B,C).