Activated PKR inhibits pancreatic β-cell proliferation through sumoylation-dependent stabilization of P53

作者：Song, Ying; Wan, XiaoMeng; Gao, Lili; Pan, Yi; Xie, WeiPing; Wang, Hong^*; Guo, Jun

来源：Molecular Immunology, 2015, 68(2): 341-349.

DOI：10.1016/j.molimm.2015.09.007

• Pancreatic beta-cell
• Proliferation
• PKR
• P53
• Sumoylation
• Ceramide

Double-stranded RNA-dependent protein kinase (PKR) is intimately involved in type 2 diabetes due to its role in insulin resistance in peripheral tissues and anti-proliferative effect on pancreatic beta-cells. Activated PKR was found to inhibit beta-cell proliferation, partially through accumulation of P53. However the molecular mechanisms underlying PKR-dependent upregulation of P53 remain unknown. The results of the present study showed that PKR can be specifically activated in PKR overexpressing beta-cells by a low dosage of the previously synthesized compound 1H-benzimidazolel-ethanol,2,3-dihydro-2-imino-a-(phenoxymethyl)-3-(phenylmethyl)-,monohydrochloride (BEPP), and this led to upregulation of P53 through sumoylation-dependent stability. Activated PKR was found to interact with sumo-conjugating enzyme Ubc9, and P53 sumoylation relies on a PKR-Ubc9 protein-protein interaction. Additionally, a ceramide signal was needed for PKR activation to be triggered by glucolipotoxicity and TNF alpha stimulation, and stabilization of P53 required endogenous ceramide accumulation. Glucolipotoxicity and pro-inflammatory cytokines therefore promote the sumoylation-dependent stability of P53 via the ceramide/PKR/Ubc9 signalling pathway that is involved in pancreatic beta-cell proliferation inhibition in the development of type 2 diabetes.

• 出版日期2015-12
• 单位南京医科大学