scholarly journals Phosphorylation and Ubiquitination of the Transcription Factor Sterol Regulatory Element-binding Protein-1 in Response to DNA Binding

2006 ◽  
Vol 281 (35) ◽  
pp. 25278-25286 ◽  
Author(s):  
Tanel Punga ◽  
Maria T. Bengoechea-Alonso ◽  
Johan Ericsson
2004 ◽  
Vol 24 (12) ◽  
pp. 2358-2364 ◽  
Author(s):  
Morgan Tréguier ◽  
Chantal Doucet ◽  
Martine Moreau ◽  
Christiane Dachet ◽  
Joëlle Thillet ◽  
...  

2004 ◽  
Vol 32 (1) ◽  
pp. 107-109 ◽  
Author(s):  
E. Tarling ◽  
A. Salter ◽  
A. Bennett

Sterol-regulatory-element-binding protein 1c (SREBP-1c) is one member of the family of transcription factors that stimulate sterol and fatty-acid biosynthesis in animal cells. Human SREBP-1c, mapped to chromosome 17p11.2, is expressed in liver, intestine, skeletal muscle and adipocytes. A section of genomic sequence from a chromosome 17 library, thought to contain the SREBP-1c promoter, was cloned. Putative transcription-factor-binding sites and a potential transcriptional start site were identified using the Genomatix Suite of sequence analysis tools (MatInspector®). Sequence analysis showed the human promoter to be 42% identical with the previously published mouse sequence. Two novel transcription-factor-binding sites were identified: those for PDX-1 (pancreatic–duodenal homoeobox-1) and HNF-4 (hepatic nuclear factor-4). Co-transfection experiments with overexpression plasmids for PDX-1 and HNF-4 suggested that both factors stimulate SREBP-1c gene expression, although further work is required to ascertain their mechanisms of action.


2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Satoshi Sakai ◽  
Yoshimi Nakagawa ◽  
Nobutake Shimojo ◽  
Taizo Kimura ◽  
Kazuko Tajiri ◽  
...  

Sterol Regulatory Element Binding Protein (SREBP)-1 is a transcription factor for triglyceride synthesis. SREBP-1 is shown to contribute to the organ damages such as pancreatic beta cell, liver, and kidney; however, it is unclear whether SREBP-1 also contributes to the cardiac pathogenesis. We made cardiac dysfunction and fibrosis model by 2-week infusion of angiotensin II (A-II, 1.44 mg/kg BW/day). Mice were divided into followings (n=5∼6 in each group): wild with vehicle (WC), wild with A-II (WA), SREBP-1 knockout mice (SREBP-KO) with vehicle (SC), and SREBP-KO with A-II (SA). WA clearly demonstrated cardiac dysfunction and severe perivascular fibrosis compared to WC; however, these findings were not observed in SA compared to SC. We analyzed gene expression by DNA microarray using the software DAVID and quantitative RT-PCR to find gene clusters mostly illustrative for these phenotypes. Gene expression of extracellular matrix (Col1a, 3a, periostin) was increased in WA. Highly scored annotations in WA were chemokines (CCL5, CXCL10) and their receptors (CCR5, CXCR3), and Th2 cytokines (IL-13 and TGFb), suggesting that chronic inflammatory and repairing responses occurred. These changes were normalized in SA compared to SC. Expression of NOX4, a component of NADPH oxidase, was significantly increased in WA and SA compared to each control in a similar extent, suggesting that the Ang II-induced oxidative stress to the heart did not differ. To elucidate why the cardiac fibrosis differed between WA and SA, we analyzed the expression of transcription factors. Nrf2, a transcription factor for detoxification and anti-oxidant gene against to reactive oxygen species (ROS), was significantly decreased in WA compared to WC; however, it did not differ between in SA and SC. Furthermore, expression of the Nrf2-inducible genes HO-1 and NQO1, antioxidant genes, was significantly decreased in WA compared to WC; meanwhile, there were no differences between in SA and SC. [Conclusion] SREBP-1 may positively contribute to the A-II-induced cardiac fibrosis via the involvement of chronic inflammatory responses, which is induced partly by the reduction of antioxidant activity.


2015 ◽  
Vol 113 (12) ◽  
pp. 1844-1852 ◽  
Author(s):  
Tsz Yan Wong ◽  
Shu-Mei Lin ◽  
Lai K. Leung

Sterol regulatory element-binding protein-2 (SREBP-2) is a pivotal transcriptional factor in cholesterol metabolism. Factors interfering with the proper functioning of SREBP-2 potentially alter plasma lipid concentrations. Consuming fruits and vegetables is associated with beneficial plasma lipid profile. The mechanism by which plant foods induce desirable lipid changes remains unclear. Apigenin, a common plant food flavonoid, was shown to modulate the nuclear translocation of SREBP-2 in the hepatic cells WRL-68 in the present study. The processing of SREBP-2 protein occurred after translation, and apigenin blocked this activation route. Further examination indicated that AMP-activated protein kinase (AMPK) was activated by the flavone, and co-administrating the AMPK-specific inhibitor compound C could release the blockage. Reporter gene assay revealed that the transactivation of sterol responsive element (SRE)-containing 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) promoter was suppressed by the flavone. Similarly, electromobility shift assay result also demonstrated a reduced DNA-binding activity on the SRE domain under the same treatment. The reduced transactivity and DNA-binding activity could be attributed to a decreased amount of SREBP-2 translocating from cytosol to nucleus as depicted by confocal microscopy. Quantitative RT-PCR assay demonstrated that the transcription of HMGCR followed the same pattern of SREBP-2 translocation. In summary, the present study showed that apigenin prevented SREBP-2 translocation and reduced the downstream gene HMGCR transcription. The minimum effective dosage should be achievable in the form of functional food consumption or dietary supplementation.


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