RPS6KB1 and sarcoma: We found that IS still inhibited mTORC1 signaling in TSC2 knockdown sarcoma U2OS cells as indicated by the reduction of p-S6K (Thr389), p-S6 (Ser235/236) and p-4E-BP1 (Ser65) (Figure 4B), indicating that IS inhibited mTORC1 signaling mainly through TSC2-independent pathway.