Selectivity in mTORC2-AKT signaling to ATP Citrate Lyase drives brown adipogenesis and de novo lipogenesis
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ABSTRACT: mTOR complex 2 (mTORC2) phosphorylates AKT in a hydrophobic motif site that is a biomarker of insulin sensitivity. In adipocytes, mTORC2 regulates glucose and lipid metabolism; however, the mechanism has been unclear because downstream AKT signaling appears unaffected by mTORC2 loss. Here, by applying immunoblotting, targeted phosphoproteomics and metabolite profiling in brown preadipocytes, we identify ATP-citrate lyase (ACLY) as a distinctly mTORC2-sensitive AKT substrate. mTORC2 appears dispensable for most other AKT actions examined indicating a previously unappreciated selectivity in mTORC2-AKT signaling. Rescue experiments show brown preadipocytes require the mTORC2/AKT/ACLY pathway to induce PPAR-gamma and establish the epigenetic landscape during differentiation. mTORC2 also acts through ACLY in mature brown adipocytes to increase ChREBP activity, histone acetylation, and gluco-lipogenic gene expression. Substrate utilization studies additionally implicate mTORC2 in promoting acetyl-CoA synthesis from acetate through acetyl-CoA synthetase 2 (ACSS2). These data suggest that a principal mTORC2 action is controlling nuclear-cytoplasmic acetyl-CoA synthesis.
INSTRUMENT(S): Q Exactive
ORGANISM(S): Mus Musculus (ncbitaxon:10090)
SUBMITTER: Judit Villen
PROVIDER: MSV000084309 | MassIVE |
REPOSITORIES: MassIVE
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