(a) Knockdown of dRagA and dRagC decreased dS6K phosphorylation (Thr 398). Drosophila S2 cells untreated (lane 2) or treated with the indicated RNAi were starved of amino acids for 1 h followed by amino acid stimulation for 30 min Phosphorylation and protein levels of dS6K were determined by immunoblotting with the indicated antibodies. 