Clathrin plaques are stable features of the plasma membrane observed in several cell types. They are abundant in muscle, where they localize at costameres which link the contractile apparatus to the sarcolemma and connect the sarcolemma to the basal lamina.
Here, a french study conducted by S. Vassilopoulos from M. Bitoun’s team* show that clathrin plaques and surrounding branched actin filaments form microdomains which anchor a three-dimensional desmin intermediate filament web. Depletion of clathrin plaque and branched actin components causes accumulation of desmin tangles in the cytoplasm.
The authors show that dynamin 2 whose mutations cause centronuclear myopathy (CNM), regulates both clathrin plaques and surrounding branched actin filaments while CNM-causing mutations lead to desmin disorganization in a CNM mouse model and patient biopsies. These results suggest a novel paradigm in cell biology, where clathrin plaques act as platforms capable of recruiting branched cortical actin which in turn anchor intermediate filaments, both essential for striated muscle formation and function.
* Pathophysiology & Therapy of Dynamin 2-related Centronuclear Myopathy, Myology Centre for Research, Insitute of Myology, Paris
