Fig. 2.

mTORC1 and ribosome biogenesis. Through phosphorylation, mTORC1 activates S6K1, which enhances rDNA transcription. mTORC1phosphorylates RPS6 to promote the synthesis of ribosomal 40S subunits, actively regulates the formation of RPS10 and RPL26, and promotes the initiation and elongation of mRNA through eIF4E and eIF2α, respectively. mTORC1 also phosphorylates and inactivates 4E-BPs to induce translation initiation. The RP assembly factor Urb1 is a downstream target of mTORC1 signaling. mTORC1 inhibits the binding of LARP1 and PABPC1 to promote mRNA translation and protein synthesis. mTORC1 mammalian target of rapamycin C1, rDNA ribosomal DNA, S6K1 S6 kinase 1, 4E-BP 4E-binding protein