Fig. 1. Expression of PKP1 and DM formation in cultured keratinocyte cell lines derived from PKP1-deficient and control individuals. (A-C) The presence of PKP1 was determined using PP1-5C2 antibody in (A) nullpB1 cells (left panel; right panel shows DAPI counterstain), (B) nullPKP2 cells, and (C) normpB1 cells. Recombinant PKP1 (B) and endogenous PKP1 (C), both localise in nuclei and to the cell membrane. (D-F) Lack of PKP1 has no discernible effect on DM ultrastructure after 8 days of confluent culture in nullpB1 cells (D), nullPKP1 cells (E) and normpB1 cells (F). Arrows indicate two DM examples per micrograph. (G) Immunoblotting of total cell extracts for PKP1 (upper panel) and Hsc-70 as loading control (lower panel) from (lane 1) null cells, (lane 2) nullpB1, (lane 3) nullpB2, (lane 4) nullPKP1, (lane 5) nullPKP2, (lane 6) normpB1. No PKP1 is detectable in null and nullpB cells. Scale bar: 10 µm (A-C); 1 µm (D-F).