PPARα-dependent Insig2a overexpression inhibits SREBP-1c processing during fasting

Jae Ho Lee, Hye Suk Kang, Hyeon Young Park, Young Ah Moon, Yu Na Kang, Byung Chul Oh, Dae Kyu Song, Jae Hoon Bae, Seung Soon Im

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10 Scopus citations

Abstract

Peroxisome-proliferator-activated receptor alpha (PPARα) and sterol regulatory element-binding protein (SREBP) play a role in regulating cellular fatty acid and cholesterol homeostasis via fatty acid oxidation and lipogenesis. The control of SREBP processing is regulated by the insulin induced gene (INSIG)2a protein, which binds SREBP to prevent SREBP translocation to the Golgi apparatus during nutrient starvation in the liver. However, the regulation of SREBP-1c processing by INSIGs during fasting and the regulatory mechanisms of the mouse Insig2a gene expression have not been clearly addressed. In the present study, we found that Insig2a was upregulated by PPARα in mouse livers and primary hepatocytes during fasting, whereas Insig2a mRNA expression was decreased in the livers of refed mice. A PPAR-responsive element between -126 bp and -114 bp in the Insig2a promoter was identified by a transient transfection assay and a chromatin immunoprecipitation assay; its role in regulation by PPARα was characterised using Pparα-null mice. These results suggest that PPARα is a trans-acting factor that enhances Insig2a gene expression, thereby suppressing SREBP-1c processing during fasting.

Original languageEnglish (US)
Article number9958
JournalScientific Reports
Volume7
Issue number1
DOIs
StatePublished - Dec 1 2017

ASJC Scopus subject areas

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    Lee, J. H., Kang, H. S., Park, H. Y., Moon, Y. A., Kang, Y. N., Oh, B. C., Song, D. K., Bae, J. H., & Im, S. S. (2017). PPARα-dependent Insig2a overexpression inhibits SREBP-1c processing during fasting. Scientific Reports, 7(1), [9958]. https://doi.org/10.1038/s41598-017-10523-7