SREBP
| SREBP-1 | ||
|---|---|---|
| Properties of human protein | ||
| Mass / length primary structure | 490 amino acids | |
| Isoforms | 4th | |
| Identifier | ||
| Gene name | SREBF1 | |
| External IDs | ||
| SREBP-2 | ||
|---|---|---|
| Properties of human protein | ||
| Mass / length primary structure | 484 amino acids | |
| Identifier | ||
| Gene name | SREBF2 | |
| External IDs | ||
SREBP stands for sterol regulatory element-binding protein . Sterol regulatory element-binding protein-1 (SREBP1) and SREBP2 are structurally similar proteins that play a crucial role in the regulation of cholesterol metabolism .
function
After proteolytic activation by MBTPS1, with their domain acting as a transcription factor, they influence the transcription of more than 20 genes that have a sequence called a sterol regulatory element (SRE) in their promoter region . SREBPs can upregulate genes when the cholesterol concentration inside the cell drops. The equilibrium within the cell is restored through an increased uptake and a simultaneous increased synthesis of cholesterol.
Different variants of SREBP play a role in medicine. For example, gene variants of SREBP1c (mutation in exon 18c) can predict serious side effects (high blood lipid levels and diabetes) in HIV therapies. The SREBP1c is responsible for the fatty acid synthesis and the SREBP2 plays a crucial role in the cholesterol metabolism .
When the cholesterol concentration in cells is low, the SREBP2 is released from the SCAP, the cholesterol sensor in cells, which is located in the membrane of the endoplasmic reticulum . SREBP2 can be activated in the Golgi by cleaving a mature peptide. This mature transcription factor can migrate into the cell nucleus and initiate the transcription of HMG-CoA reductase and LDL receptors . As a result, on the one hand, more cholesterol is synthesized and, on the other hand, more cholesterol is delivered from the bloodstream into the cell via LDL .
Statins exploit this mechanism by blocking HMG-CoA reductase. This primarily prevents the production of cholesterol. The blood cholesterol level is also lowered because the low cholesterol concentration in the cell activates the LDL receptor production and more LDL is absorbed from the bloodstream into the cell.
literature
- Jeremy M. Berg, John L. Tymoczko, Lubert Stryer : Biochemistry. 6 edition, Spektrum Akademischer Verlag, Heidelberg 2007. ISBN 978-3-8274-1800-5 .
- Donald Voet, Judith G. Voet: Biochemistry. 3rd edition, John Wiley & Sons, New York 2004. ISBN 0-471-19350-X .
- Bruce Alberts , Alexander Johnson, Peter Walter, Julian Lewis, Martin Raff, Keith Roberts: Molecular Biology of the Cell , 5th Edition, Taylor & Francis 2007, ISBN 978-0815341062 .
Web links
- SREBP1. In: Online Mendelian Inheritance in Man . (English).
- SREBP2. In: Online Mendelian Inheritance in Man . (English).
Individual evidence
- ^ A b Rassow, Hauser, Netzker, Deutzmann: Low Density Lipoproteins . In: biochemistry . Thieme, ISBN 978-3-13-125354-5 .