AMP-activated protein kinase regulates PEPCK gene expression by direct phosphorylation of a novel zinc finger transcription factor.

Nutritional Epidemiology Program, Bio-Index Project, National Institute of Health and Nutrition, 1-23-1 Toyama, Shinjyuku, Tokyo 162-8636, Japan.

Biochemical and biophysical research communications 2006 Dec 29

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AMP-activated protein kinase (AMPK) acts as an intracellular sensor for maintaining the energy balance. Activation of AMPK switches on ATP-generating process while switches off ATP-consuming process. It achieves these effects by phosphorylation of downstream metabolic enzymes. It has been proposed that AMPK also regulates gene expression through phosphorylation of certain transcription factors; however its molecular mechanism is not fully understood. Here we show the cloning and characterization of a novel zinc finger transcription factor referred to as AREBP. AREBP is phosphorylated at Ser(470) by AMPK. Phosphorylation reduces the DNA-binding activity of AREBP. Transient transfection experiments indicate that wild-type AREBP, but not Ser(470) to Ala(470) substituted non-phosphorylating mutant, represses gene expression of the phosphoenolpyruvate carboxykinase (PEPCK), a key enzyme of gluconeogenesis. RNA interference-mediated reduction of endogenous AREBP expression attenuates AMPK-induced PEPCK down-regulation. These results implicate AREBP as a novel key modulator of PEPCK gene expression regulated by AMPK.

Citation

Erina Inoue, Jun Yamauchi. AMP-activated protein kinase regulates PEPCK gene expression by direct phosphorylation of a novel zinc finger transcription factor. Biochemical and biophysical research communications. 2006 Dec 29;351(4):793-9