| First Author | Gotoh S | Year | 2017 |
| Journal | Cell Signal | Volume | 40 |
| Pages | 200-209 | PubMed ID | 28911860 |
| Mgi Jnum | J:357977 | Mgi Id | MGI:6871454 |
| Doi | 10.1016/j.cellsig.2017.09.003 | Citation | Gotoh S, et al. (2017) Glucose elicits serine/threonine kinase VRK1 to phosphorylate nuclear pregnane X receptor as a novel hepatic gluconeogenic signal. Cell Signal 40:200-209 |
| abstractText | Low glucose stimulated phosphorylation of pregnane X receptor (PXR) at Ser(350) in correlation with an increased gluconeogenesis in human hepatoma-derived HepG2 cells. Only glucose, but neither insulin nor glucagon, stimulated this phosphorylation. Here, serine/threonine kinase, vaccinia related kinase 1 (VRK1)-mediated phosphorylation of PXR is now defined as this glucose-elicited novel signal. In low glucose conditions, VRK1 directly phosphorylates PXR at Ser(350), enabling PO3-PXR to scaffold protein phosphatase PP2Calpha. This PP2Calpha dephosphorylates serine/threonine kinase 2 (SGK2) at Thr(193). This dephosphorylation dissociates SGK2 from and actives the phosphoenolpyruvate carboxykinase 1 (PCK1) gene as phosphorylated SGK2 binds and represses the gene. Conversely, VRK1 self-represses its activity to phosphorylate PXR through cyclin-dependent kinase 2 (CDK2) in high glucose conditions, resulting in the repression of the PCK1 gene. This PXR phosphorylation was also observed in fasting mouse livers. Thus, the VRK1-CDK2-PXR-PP2Calpha-SGK2 pathway can be a novel physiological cell signaling that regulates gluconeogenesis in response to glucose. |
