Super-Resolution Imaging Reveals Stretch-Induced Architectural Rearrangement of Desmoplakin in Desmosomes.

Desmosomes (DSMs) are intercellular junctions essential for providing mechanical resilience to tissues, particularly the epidermis. Desmoplakin (DP) is a key DSM protein which anchors plaque proteins to keratins, thereby ensuring tissue integrity under mechanical stress. Clinically, DP mutations impair keratinocyte adhesion and structural integrity, leading to skin fragility disorders. However, how mechanical forces influence DSM architecture is poorly understood. We hypothesized that physiological stretch could alter DP architecture in DSMs. To test this, we subjected normal human epidermal keratinocytes (NHEKs) and DP-knockout human keratinocytes expressing either DPI-mEGFP, DP1a-mEGFP, or DP2-mEGFP to mechanical stretch using the Flexcell system (13% uniaxial strain for 30 minutes). Direct stochastic optical reconstruction microscopy (dSTORM) was used to visualize DP architecture with 20 nm resolution. We found mechanical stretch significantly increased the distance between DP cytoplasmic tails compared to static controls across all cell lines. In contrast, there was no significant change in the N-terminal head domain under stretch, highlighting the tail domain as the primary site of mechanical adaptation. This work enhances our understanding of how DSMs and DP isoforms respond to biomechanical forces, revealing that the C-term of DP undergoes a strain-induced conformational shift, reorganizing the DSM architecture in response to physiological stress. Ultimately, elucidating the spatial and biomechanical behavior of DP will deepen our understanding of its contribution to dermatological health and disease.