The mammalian Target Of Rapamycin (mTOR) is a master regulator of growth. mTOR is a protein kinase that exists in two distinct complexes in the cell and transduces virtually all anabolic signals from the environment: nutrients, such as glucose and amino acids, growth factor peptides, such as insulin and insulin like growth factors, oxygen, mitochondrial metabolites, energy status. mTOR is required to sustain cell responses to nutrient availability including cell growth, proliferation, macromolecule biosynthesis, and suppress autophagy. During the past ten years we have generated and characterized a wide panel of mouse mutants in the mTOR pathway. We were involved in revealing specific phenotypes that increased our knowledge of mTOR roles in pathophysiology: mutants with small cells, mutants resistant to tumorigenesis in specific tissues and after specific oncogenic insults, mutants mimicking caloric restriction and promoting longevity, mutants with muscle dystrophy, mutants with altered insulin action.The overall goal of our research proposal for the next five years is twofold. From one hand we want to better understand fundamental processes including cell size control and organismal longevity. To this end we want to determine the molecular targets of the mTORC1/S6 kinase cassette that may explain the alterations in cell size and lifespan when these kinases are deregulated (project 1). From the other hand we want to understand and cure rare human genetic diseases that arise from pathological changes in the activity of the mTOR pathway in children or that may benefit from therapeutical intervention on this pathway. These diseases include Tuberous Sclerosis Complex, PEComas and hemangiomas (project 2), metabolic diseases (projects 3), lysosomal storage diseases (project 4). The translational approaches in this proposal will stem from a close interaction with multiple Medical Dept. in our shared research campus of the Necker Children Hospital.