Changes in the morphology of NIH3T3 cells expressing novel mTOR mutants were determined as described previously [42 (link),12 (link)]. Briefly, NIH3T3 cells stably transfected with the empty vector, wild-type mTOR, and the indicated mTOR mutants were plated in 60-mm culture plates (Corning, NY) at a density of 3 X 105 cells. Cells were cultivated one day in regular medium (DMEM+10% FCS+G418 800µg/ml), followed by examination of the cell morphology under a microscope (Nikon Eclipse Ti-U, Tokyo, Japan).