Actin Assembly Proteins in the Heart

 

Myofibrillogenesis is a crucial part of heart development. It results in a highly ordered array of identical multiprotein subunits, the sarcomeres. They contain actin and myosin filaments, which interact with each other to produce force.

Various models have been proposed to explain the formation of myofibrils. Depending on the model organism or cell type, studies suggested the existence of either stress fibre like structures or pre-myofibrils as precursors and backbone for myofibrillogenesis.

Regardless of the model, the initial myofibrillar structures are formed at integrin adhesion sites and contain actin filaments.  However, up until now it is unclear which actin assembly proteins are involved in their formation.

Actin assembly is a very tightly regulated process with specialized assembly factors for different actin structures. Our data suggests that formin family proteins are involved in the formation of mature myofibrils at several stages and regulated by mechanical signals. Here we want to dissect when and how these proteins are recruited, turned on, or off in order to form the mature myofibrils.