Actomyosin forces trigger a conformational change in desmoplakin within desmosomes.

Abstract

Desmosomes are essential cell-cell adhesion organelles that enable tension-prone tissue, like the skin and heart, to withstand mechanical stress. Desmosomal anomalies are associated with numerous epidermal disorders and cardiomyopathies. Despite their critical role in maintaining tissue resilience, an understanding of how desmosomes sense and respond to mechanical stimuli is lacking. Here, we use a combination of super-resolution imaging, FRET-based tension sensors, atomistic computer simulations, and biochemical assays to demonstrate that actomyosin forces induce a conformational change in desmoplakin, a critical cytoplasmic desmosomal protein. We show that in human breast cancer MCF7 cells, actomyosin contractility reorients keratin intermediate filaments and directs force to desmoplakin along the keratin filament backbone. These forces induce a conformational change in the N-terminal plakin domain of desmoplakin, converting this domain from a folded (closed) to an extended (open) conformation. Our findings establish that desmoplakin is mechanosensitive and responds to changes in cellular load by undergoing a force-induced conformational change.