Genetic and biochemical characterization of dTOR, the Drosophila homolog of the target of rapamycin

The adaptation of growth in response to nutritional changes is essential fo r the proper development of all organisms. Here we describe the identificat ion of the Drosophila homolog of the target of rapamycin (TOR), a candidate effector for nutritional sensing. Genetic and biochemical analyses indicat e that dTOR impinges on the insulin signaling pathway by autonomously affec ting growth through modulating the activity of dS6K. However, in contrast t o other components in the insulin signaling pathway, partial loss of dTOR f unction preferentially reduces growth of the endoreplicating tissues. These results are consistent with dTOR residing on a parallel amino acid sensing pathway.