Sterol regulatory element-binding protein 2 (SREBP-2) also known as sterol regulatory element binding transcription factor 2 (SREBF2) is a protein that in humans is encoded by the SREBF2 gene. [5]
Sterol regulatory element-binding protein 2 (SREBP-2) also known as sterol regulatory element binding transcription factor 2 (SREBF2) is a protein that in humans is encoded by the SREBF2 gene. [5]
This gene encodes a ubiquitously expressed transcription factor that controls cholesterol homeostasis by stimulating transcription of sterol-regulated genes. The encoded protein contains a basic helix-loop-helix leucine zipper (bHLH-Zip) domain. [6] Various single nucleotide polymorphisms (SNPs) of the SREBF2 have been identified and some of them are found to be associated with higher risk of knee osteoarthritis. [7]
SREBF2 has been shown to interact with INSIG1 [8] [9] and CREB-binding protein. [10]
HMG-CoA reductase is the rate-controlling enzyme of the mevalonate pathway, the metabolic pathway that produces cholesterol and other isoprenoids. HMGCR catalyzes the conversion of HMG-CoA to mevalonic acid, a necessary step in the biosynthesis of cholesterol. Normally in mammalian cells this enzyme is competitively suppressed so that its effect is controlled. This enzyme is the target of the widely available cholesterol-lowering drugs known collectively as the statins, which help treat dyslipidemia.
Joseph Leonard Goldstein ForMemRS is an American biochemist. He received the Nobel Prize in Physiology or Medicine in 1985, along with fellow University of Texas Southwestern researcher, Michael Brown, for their studies regarding cholesterol. They discovered that human cells have low-density lipoprotein (LDL) receptors that remove cholesterol from the blood and that when LDL receptors are not present in sufficient numbers, individuals develop hypercholesterolemia and become at risk for cholesterol related diseases, notably coronary heart disease. Their studies led to the development of statin drugs.
Michael Stuart Brown ForMemRS is an American geneticist and Nobel laureate. He was awarded the Nobel Prize in Physiology or Medicine with Joseph L. Goldstein in 1985 for describing the regulation of cholesterol metabolism.
A leucine zipper is a common three-dimensional structural motif in proteins. They were first described by Landschulz and collaborators in 1988 when they found that an enhancer binding protein had a very characteristic 30-amino acid segment and the display of these amino acid sequences on an idealized alpha helix revealed a periodic repetition of leucine residues at every seventh position over a distance covering eight helical turns. The polypeptide segments containing these periodic arrays of leucine residues were proposed to exist in an alpha-helical conformation and the leucine side chains from one alpha helix interdigitate with those from the alpha helix of a second polypeptide, facilitating dimerization.
In biochemistry, lipogenesis is the conversion of fatty acids and glycerol into fats, or a metabolic process through which acetyl-CoA is converted to triglyceride for storage in fat. Lipogenesis encompasses both fatty acid and triglyceride synthesis, with the latter being the process by which fatty acids are esterified to glycerol before being packaged into very-low-density lipoprotein (VLDL). Fatty acids are produced in the cytoplasm of cells by repeatedly adding two-carbon units to acetyl-CoA. Triacyglycerol synthesis, on the other hand, occurs in the endoplasmic reticulum membrane of cells by bonding three fatty acid molecules to a glycerol molecule. Both processes take place mainly in liver and adipose tissue. Nevertheless, it also occurs to some extent in other tissues such as the gut and kidney. A review on lipogenes in the brain was published in 2008 by Lopez and Vidal-Puig. After being packaged into VLDL in the liver, the resulting lipoprotein is then secreted directly into the blood for delivery to peripheral tissues.
Sterol regulatory element-binding proteins (SREBPs) are transcription factors that bind to the sterol regulatory element DNA sequence TCACNCCAC. Mammalian SREBPs are encoded by the genes SREBF1 and SREBF2. SREBPs belong to the basic-helix-loop-helix leucine zipper class of transcription factors. Unactivated SREBPs are attached to the nuclear envelope and endoplasmic reticulum membranes. In cells with low levels of sterols, SREBPs are cleaved to a water-soluble N-terminal domain that is translocated to the nucleus. These activated SREBPs then bind to specific sterol regulatory element DNA sequences, thus upregulating the synthesis of enzymes involved in sterol biosynthesis. Sterols in turn inhibit the cleavage of SREBPs and therefore synthesis of additional sterols is reduced through a negative feed back loop.
Squalene synthase (SQS) or farnesyl-diphosphate:farnesyl-diphosphate farnesyl transferase is an enzyme localized to the membrane of the endoplasmic reticulum. SQS participates in the isoprenoid biosynthetic pathway, catalyzing a two-step reaction in which two identical molecules of farnesyl pyrophosphate (FPP) are converted into squalene, with the consumption of NADPH. Catalysis by SQS is the first committed step in sterol synthesis, since the squalene produced is converted exclusively into various sterols, such as cholesterol, via a complex, multi-step pathway. SQS belongs to squalene/phytoene synthase family of proteins.
Sterol regulatory element-binding protein cleavage-activating protein, also known as SREBP cleavage-activating protein or SCAP is a protein that in humans is encoded by the SCAP gene.
CAMP responsive element binding protein 1, also known as CREB-1, is a protein that in humans is encoded by the CREB1 gene. This protein binds the cAMP response element, a DNA nucleotide sequence present in many viral and cellular promoters. The binding of CREB1 stimulates transcription.
Sterol regulatory element-binding transcription factor 1 (SREBF1) also known as sterol regulatory element-binding protein 1 (SREBP-1) is a protein that in humans is encoded by the SREBF1 gene.
Activating transcription factor 4 , also known as ATF4, is a protein that in humans is encoded by the ATF4 gene.
Activating transcription factor 6, also known as ATF6, is a protein that, in humans, is encoded by the ATF6 gene and is involved in the unfolded protein response.
Membrane-bound transcription factor site-1 protease, or site-1 protease (S1P) for short, also known as subtilisin/kexin-isozyme 1 (SKI-1), is an enzyme that in humans is encoded by the MBTPS1 gene. S1P cleaves the endoplasmic reticulum loop of sterol regulatory element-binding protein (SREBP) transcription factors.
Membrane-bound transcription factor site-2 protease, also known as S2P endopeptidase or site-2 protease (S2P), is an enzyme encoded by the MBTPS2 gene which liberates the N-terminal fragment of sterol regulatory element-binding protein (SREBP) transcription factors from membranes. S2P cleaves the transmembrane domain of SREPB, making it a member of the class of intramembrane proteases.
DNA-binding protein inhibitor ID-3 is a protein that in humans is encoded by the ID3 gene.
Insulin induced gene 1, also known as INSIG1, is a protein which in humans is encoded by the INSIG1 gene.
Oxysterol-binding protein 1 is a protein that in humans is encoded by the OSBP gene.
Insulin induced gene 2, also known as INSIG2, is a protein which in humans is encoded by the INSIG2 gene.
StAR-related lipid transfer protein 4 (STARD4) is a soluble protein involved in cholesterol transport. It can transfer up to 7 sterol molecules per minute between artificial membranes.
A sterol-sensing domain (SSD) is a protein domain which consists of 180 amino acids forming five transmembrane segments capable of binding sterol groups. This type of domain is present in proteins involved in cholesterol metabolism and signalling.
This article incorporates text from the United States National Library of Medicine, which is in the public domain.
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