Fig. 3. Mechanical stretch causes relocation of desmoplakin from desmosomes in DM-EBS keratinocytes. KEB-7 cells were stretched using a cyclic stretch with a frequency of 4 Hz and amplitude of 12% for varying times. (A) Control cells before stretch; (B) DM-EBS cells before stretch; (C) Control cells after 120 minutes of stretch; (D) DM-EBS cells after 120 minutes of stretch. Elongation of desmoplakin staining is seen in the majority of control cells after stretch (C, arrow). Desmoplakin staining remains localized to desmosomes where the keratin network is maintained on at least one cell edge (D, arrow). Cells were stained using a polyclonal antibody against keratin 5 (BL18) and a monoclonal antibody against desmoplakin (11-5F). Bars, 10 µm. (E) Desmoplakin staining elongates in response to stretch in wild-type keratinocytes. Forty regions of desmoplakin staining were measured before and after stretch. Results show that desmoplakin staining elongates approximately threefold in response to stretch, suggesting an inherent elasticity within desmosomes that involves desmoplakin.