(d) RagAT21N and RagCQ120L do not block Rheb-induced S6K phosphorylation. RagAT21N and RagCQ120L (200 ng each) were transfected into HEK293 cells with or without Rheb construct (20 ng). S6K was included in the co-transfection. Phosphorylation and protein levels of the transfected proteins were determined by immunoblotting with appropriate antibodies, as indicated. Full scans of blots are provided in Supplementary Information, Fig. S6. 