Fbxo7 promotes Cdk6 activity to inhibit PFKP and glycolysis in T cells
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ABSTRACT: Deregulated Fbxo7 expression is associated with many pathologies, including anaemia, male sterility, cancer, and Parkinson’s disease, demonstrating its critical role in a variety of cell types. Although Fbxo7 is an F-box protein that recruits substrates for SCF-type E3 ubiquitin ligases, it also promotes the formation of cyclin D/Cdk6/p27 complexes in an E3-ligase independent fashion. We discovered PFKP, the major gatekeeper of glycolysis, in a screen for Fbxo7 substrates. PFKP has been previously shown to be a critical substrate of Cdk6 for the viability of T-ALL cells experiencing high levels of reactive oxygen species. We investigated the molecular relationships between Fbxo7, Cdk6 and PFKP, and the functional effect Fbxo7 has on T cell metabolism, viability, and activation. Fbxo7 promotes Cdk6-independent ubiquitination and Cdk6-dependent phosphorylation of PFKP. Importantly Fbxo7-deficient cells have reduced Cdk6 activity, and haematopoietic and lymphocytic cell lines show a significant dependency on Fbxo7. CD4+ T cells with reduced Fbxo7 have increased glycolysis, and lower cell viability and activation levels. Metabolomic studies of activated CD4+ T cells confirm increased glycolytic flux in Fbxo7-deficient cells, as well as altered nucleotide biosynthesis and arginine metabolism. We show Fbxo7 expression is glucose-responsive, and we propose Fbxo7 inhibits PFKP and glycolysis via its activation of Cdk6.
ORGANISM(S): Mouse Mus Musculus
TISSUE(S): T-cells
SUBMITTER: Heike Laman
PROVIDER: ST001986 | MetabolomicsWorkbench | Fri Oct 29 00:00:00 BST 2021
REPOSITORIES: MetabolomicsWorkbench
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