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Zhao LF, Iwasaki Y, Nishiyama M, Taguchi T, Tsugita M, Okazaki M, Nakayama S, Kambayashi M, Fujimoto S, Hashimoto K, Murao K, Terada Y. Liver X receptor α is involved in the transcriptional regulation of the 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase gene. Diabetes 2012; 61:1062-71. [PMID: 22415873 PMCID: PMC3331782 DOI: 10.2337/db11-1255] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The activity of 6-phosphofructo-1-kinase is strictly controlled by fructose-2,6-bisphosphate, the level of which is regulated by another enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK2/FBP2). PFK2/FBP2 is a bifunctional enzyme, having kinase and phosphatase activities, and regulates both glycolysis and gluconeogenesis. Here, we examined the hormonal regulation of the PFK2/FBP2 gene in vitro using the reporter assay, the electromobility shift assay (EMSA), and the chromatin immunoprecipitation (ChIP) assay in HuH7 cells and also using the mouse liver in vivo. We found that the transcriptional activity of the PFK2/FBP2 gene was stimulated by insulin and inhibited by cAMP and glucocorticoid. Liver X receptor (LXR) α showed a potent and specific stimulatory effect on PFK2/FBP2 gene transcription. Deletion and mutagenesis analyses identified the LXR response element (LXRE) in the 5'-promoter region of the PFK2/FBP2 gene. Binding of LXRα was confirmed by the EMSA and ChIP assay. Endogenous PFK2/FBP2 mRNA in the mouse liver was increased in the fasting/refeeding state compared with the fasting state. Altogether, PFK2/FBP2 gene transcription is found to be regulated in a way that is more similar to other glycolytic enzyme genes than to gluconeogenic genes. Furthermore, our data strongly suggest that LXRα is one of the key regulators of PFK2/FBP2 gene transcription.
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Affiliation(s)
- Li-Feng Zhao
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Kochi, Japan
| | - Yasumasa Iwasaki
- Health Care Center, Kochi University, Kochi, Japan
- Corresponding author: Yasumasa Iwasaki,
| | - Mitsuru Nishiyama
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Kochi, Japan
| | - Takafumi Taguchi
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Kochi, Japan
| | - Makoto Tsugita
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Kochi, Japan
| | - Mizuho Okazaki
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Kochi, Japan
| | - Shuichi Nakayama
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Kochi, Japan
| | | | - Shimpei Fujimoto
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Kochi, Japan
| | - Koshi Hashimoto
- Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Koji Murao
- Department of Advanced Medicine, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Yoshio Terada
- Department of Endocrinology, Metabolism, and Nephrology, Kochi Medical School, Kochi University, Kochi, Japan
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