The mechanical role of a cytoskeletal protein, Synemin, in bone, heart and skeletal muscle

Intermediate filaments (IFs) represent a major cytoskeletal network contributing to force transmission, cell shape and structure, adhesion and motility, subcellular scaffolding and tissue resilience, thereby modulating a range of cellular activities. Life-threatening disorders associated with IF mutations have pushed investigations to study IFs of mammalian cells in culture and in vivo. Keratin and Lamin related disorders, Desmin-related myopathy, Muscular Dystrophies, Alexander disease are just examples of pathologies related to IFs. Synemin, a type IV IF has become a target for research since its AKAP role in the heart was reported. Here we summarize our results with Synemin “knock-out” mice showing that Synemin plays a significant role in skeletal and cardiac muscle, leading to a mild skeletal myopathy and a mixed cardiomyopathy. We also report an important role of Synemin, with the absence of Synemin leading to osteopenia.