- Lee, Gina;
- Zheng, Yuxiang;
- Cho, Sungyun;
- Jang, Cholsoon;
- England, Christina;
- Dempsey, Jamie M;
- Yu, Yonghao;
- Liu, Xiaolei;
- He, Long;
- Cavaliere, Paola M;
- Chavez, Andre;
- Zhang, Erik;
- Isik, Meltem;
- Couvillon, Anthony;
- Dephoure, Noah E;
- Blackwell, T Keith;
- Yu, Jane J;
- Rabinowitz, Joshua D;
- Cantley, Lewis C;
- Blenis, John
mTORC1 is a signal integrator and master regulator of cellular anabolic processes linked to cell growth and survival. Here, we demonstrate that mTORC1 promotes lipid biogenesis via SRPK2, a key regulator of RNA-binding SR proteins. mTORC1-activated S6K1 phosphorylates SRPK2 at Ser494, which primes Ser497 phosphorylation by CK1. These phosphorylation events promote SRPK2 nuclear translocation and phosphorylation of SR proteins. Genome-wide transcriptome analysis reveals that lipid biosynthetic enzymes are among the downstream targets of mTORC1-SRPK2 signaling. Mechanistically, SRPK2 promotes SR protein binding to U1-70K to induce splicing of lipogenic pre-mRNAs. Inhibition of this signaling pathway leads to intron retention of lipogenic genes, which triggers nonsense-mediated mRNA decay. Genetic or pharmacological inhibition of SRPK2 blunts de novo lipid synthesis, thereby suppressing cell growth. These results thus reveal a novel role of mTORC1-SRPK2 signaling in post-transcriptional regulation of lipid metabolism and demonstrate that SRPK2 is a potential therapeutic target for mTORC1-driven metabolic disorders.