Microcompartments in the Drosophila heart and the mammalian brain: general features and common principles

Microcompartments are sub-organellar functional units and may have an important role in cellular physiology. They can act as highly dynamic or even transiently forming organizing compartments within cells. In this review, we would like to extend the concept of microcompartments as subcellular structures in individual cells in a way that it includes specializations that occur between different cells and between cells and components of the extracellular matrix. To develop the general features and properties of these structures, we will present two quite different examples - the development and maturation of the Drosophila heart and the dynamics of synaptic contacts in the mammalian brain. We argue that the molecular architecture, the function and the maintenance of these specializations follows common principles independent of the organ or the organism under investigation. They fulfill the criteria for being proper microcompartments, including their function as local units for the segregation of responses, their ability to serve as organizing platforms in a temporally and spatially highly restricted manner, and their regulation through instructions from neighboring cells or extracellular matrix components in a locally restricted and autonomous manner.