Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10769899 | Biochemical and Biophysical Research Communications | 2005 | 7 Pages |
Abstract
Insulin and cAMP have opposing effects on de novo fatty acid synthesis in liver and in cultured hepatocytes mediated by sterol-regulatory element binding protein (SREBP). To determine whether these agents regulate the cleavage of full-length SREBP to generate the transcriptionally active N-terminal fragment (nSREBP) in primary rat hepatocytes, an adenoviral vector (Ad-SREBP-1a) was constructed to constitutively express full-length SREBP-1a. Insulin increased, and dibutyryl (db)-cAMP inhibited, generation of nSREBP-1a from its full-length precursor. Insulin stimulated processing of SREBP-1a within 1Â h, and the effect was sustained for at least 24Â h. The initial stimulation of SREBP processing by insulin preceded measurable reduction in Insig-2 mRNA levels. Rat hepatocytes were also infected with an adenovirus expressing the nuclear form of SREBP-1c (Ad-nSREBP-1c). Insulin increased the half-life of constitutively expressed nSREBP-1c, and this effect of insulin was also inhibited by db-cAMP.
Related Topics
Life Sciences
Biochemistry, Genetics and Molecular Biology
Biochemistry
Authors
Chandrahasa R. Yellaturu, Xiong Deng, Lauren M. Cagen, Henry G. Wilcox, Edwards A. Park, Rajendra Raghow, Marshall B. Elam,