| First Author | Lee Y | Year | 2014 |
| Journal | Nature | Volume | 510 |
| Issue | 7506 | Pages | 547-51 |
| PubMed ID | 24870244 | Mgi Jnum | J:213271 |
| Mgi Id | MGI:5584035 | Doi | 10.1038/nature13267 |
| Citation | Lee Y, et al. (2014) Cyclin D1-Cdk4 controls glucose metabolism independently of cell cycle progression. Nature 510(7506):547-51 |
| abstractText | Insulin constitutes a principal evolutionarily conserved hormonal axis for maintaining glucose homeostasis; dysregulation of this axis causes diabetes. PGC-1alpha (peroxisome-proliferator-activated receptor-gamma coactivator-1alpha) links insulin signalling to the expression of glucose and lipid metabolic genes. The histone acetyltransferase GCN5 (general control non-repressed protein 5) acetylates PGC-1alpha and suppresses its transcriptional activity, whereas sirtuin 1 deacetylates and activates PGC-1alpha. Although insulin is a mitogenic signal in proliferative cells, whether components of the cell cycle machinery contribute to its metabolic action is poorly understood. Here we report that in mice insulin activates cyclin D1-cyclin-dependent kinase 4 (Cdk4), which, in turn, increases GCN5 acetyltransferase activity and suppresses hepatic glucose production independently of cell cycle progression. Through a cell-based high-throughput chemical screen, we identify a Cdk4 inhibitor that potently decreases PGC-1alpha acetylation. Insulin/GSK-3beta (glycogen synthase kinase 3-beta) signalling induces cyclin D1 protein stability by sequestering cyclin D1 in the nucleus. In parallel, dietary amino acids increase hepatic cyclin D1 messenger RNA transcripts. Activated cyclin D1-Cdk4 kinase phosphorylates and activates GCN5, which then acetylates and inhibits PGC-1alpha activity on gluconeogenic genes. Loss of hepatic cyclin D1 results in increased gluconeogenesis and hyperglycaemia. In diabetic models, cyclin D1-Cdk4 is chronically elevated and refractory to fasting/feeding transitions; nevertheless further activation of this kinase normalizes glycaemia. Our findings show that insulin uses components of the cell cycle machinery in post-mitotic cells to control glucose homeostasis independently of cell division. |
