Muscle building: the making of a fly steak

Mature muscle cells are extremely protein dense. Their internal organisation positions their nuclei, the energy producing mitochondria and the force producing myofibrils at stereotypic locations optimised for force production and energy flow. The contractile forces and the high packing density result in the generation of high pressure on the cellular organelles, including the nuclei. Using the Drosophila flight muscles as model system, I will discuss how mitochondria are positioned relative to the assembling myofibrils, and how both mature during development. Their growth builds up a high mechanical pressure deforming the nuclei. I will present evidence for a pressure sensing mechanism in the nuclei, which is important to mediate the metabolic switch enabling muscle maturation during development