Interacting selectively and non-covalently with cholesterol (cholest-5-en-3-beta-ol); the principal sterol of vertebrates and the precursor of many steroids, including bile acids and steroid hormones.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
Enables the directed movement of cholesterol into, out of or within a cell, or between cells. Cholesterol is the principal sterol of vertebrates and the precursor of many steroids, including bile acids and steroid hormones.
The transfer of insoluble cholesteryl esters among lipoprotein particles is a vital step in normal cholesterol homeostasis and may be involved in the development of atherosclerosis. Extrahepatic tissues lack the enzymes required for the degradation of sterols to the excretable form of bile acids. Cholesterol synthesized in these tissues in excess of that needed for the synthesis of cell membranes or steroid hormones must accordingly be returned through the plasma to the liver for catabolism. The series of reactions involved has been termed reverse cholesterol transport. Catalysed steps of this pathway are believed to include an efflux from peripheral cells, which generates a diffusion gradient between these membranes and extracellular fluid; esterification of this cholesterol by lecithin-cholesterol acyltransferase (LCAT) (phosphatidylcholine-sterol acyltransferase) acting on species of high-density lipoproteins; transfer of the cholesteryl esters formed (largely to low- and very low-density lipoproteins) (LDL and VLDL) by a cholesteryl ester transfer protein (CETP); and removal of these lipoproteins, together with their cholesteryl ester content, by the liver through receptor-mediated and nonspecific endocytosis. Of these steps, the CETP reaction is the least characterized. Several laboratories have reported the purification from human plasma of proteins active on cholesteryl ester transfer between lipoprotein particles and possibly between cells and plasma. However, the reported relative molecular mass (Mr), abundance and specificity of the purified activities have differed considerably. We have recently described the preparation of a highly active CETP of Mr 74,000 purified about 100,000-fold from human plasma, which may represent the functional component of earlier preparations. Using a partial amino-acid sequence from this purified protein, CETP complementary DNA derived from human liver DNA has been cloned and sequenced and the cloned DNA used to detect CETP messenger RNA in a number of human tissues.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
J. Biol. Chem. 262, 2275-2282 (1987)[PubMed:3818596]
The cholesteryl ester transfer protein (CETP) binds to plasma lipoproteins and promotes transfer of cholesteryl esters between the lipoproteins. CETP has been purified 55,000-fold, with a 27% recovery of activity, from the d greater than 1.21 g/ml fraction of human plasma. In the final purification step, partially purified CETP is incubated with a synthetic lipid emulsion consisting of phosphatidylcholine, triglyceride, and fatty acid, and the bound activity, which elutes in the void volume, is separated from nonbound proteins by gel filtration on Sepharose 4B. Sodium dodecyl sulfate-gel analysis of fractions containing bound activity shows the presence of a single protein with an apparent Mr of 74,000. Inclusion of fatty acid in this emulsion was required to prevent the binding of a contaminant protein. However, incubation of CEPT with fatty acid emulsions containing lipid peroxides resulted in substantial inactivation and covalent degradation of the 74-kDa protein. This could be prevented by the inclusion of antioxidants during preparation of the emulsion. Solvent extraction of emulsion-bound CEPT gave a delipidated, active preparation. Purified IgG from a rabbit immunized with the 74-kDa protein completely removed activity from partially purified fractions. Amino acid analysis of the purified protein showed it to contain an unusually high content (45%) of nonpolar residues; the calculated hydrophobicity was greater than that of any other plasma apolipoprotein. These results show human CETP to be a unique plasma apolipoprotein with an apparent Mr of 74,000 which is hydrophobic, self-associating, and susceptible to covalent degradation by lipid peroxides.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
Interacting selectively and non-covalently with phosphatidylcholine, a class of glycophospholipids in which a phosphatidyl group is esterified to the hydroxyl group of choline.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
Enables the directed movement of phospholipids into, out of or within a cell, or between cells. Phospholipids are a class of lipids containing phosphoric acid as a mono- or diester.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
Plasma high density lipoproteins (HDL) are a negative risk factor for atherosclerosis. Increased HDL is sometimes clustered in families, but a genetic basis has never been clearly documented. The plasma cholesteryl ester transfer protein (CETP) catalyses the transfer of cholesteryl ester from HDL to other lipoproteins and therefore might influence HDL levels. Using monoclonal antibodies, we show that CETP is absent in two Japanese siblings who have markedly increased and enlarged HDL. Furthermore, they are homozygous for a point mutation in the 5'-splice donor site of intron 14 of the gene for CETP, a change that is incompatible with normal splicing of pre-messenger RNA. The results indicate that the family has an inherited deficiency of CETP due to a gene splicing defect, and illustrate the key role that CETP has in human HDL metabolism.
The chemical reactions and pathways involving cholesterol, cholest-5-en-3 beta-ol, the principal sterol of vertebrates and the precursor of many steroids, including bile acids and steroid hormones. It is a component of the plasma membrane lipid bilayer and of plasma lipoproteins and can be found in all animal tissues.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
Plasma high density lipoproteins (HDL) are a negative risk factor for atherosclerosis. Increased HDL is sometimes clustered in families, but a genetic basis has never been clearly documented. The plasma cholesteryl ester transfer protein (CETP) catalyses the transfer of cholesteryl ester from HDL to other lipoproteins and therefore might influence HDL levels. Using monoclonal antibodies, we show that CETP is absent in two Japanese siblings who have markedly increased and enlarged HDL. Furthermore, they are homozygous for a point mutation in the 5'-splice donor site of intron 14 of the gene for CETP, a change that is incompatible with normal splicing of pre-messenger RNA. The results indicate that the family has an inherited deficiency of CETP due to a gene splicing defect, and illustrate the key role that CETP has in human HDL metabolism.
The directed movement of cholesterol, cholest-5-en-3-beta-ol, into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
The acquisition, loss or modification of a protein or lipid within a high-density lipoprotein particle, including the hydrolysis of triglyceride by hepatic lipase, with the subsequent loss of free fatty acid, and the transfer of cholesterol esters from LDL to a triglyceride-rich lipoprotein particle by cholesteryl ester transfer protein (CETP), with the simultaneous transfer of triglyceride to LDL.
Plasma high density lipoproteins (HDL) are a negative risk factor for atherosclerosis. Increased HDL is sometimes clustered in families, but a genetic basis has never been clearly documented. The plasma cholesteryl ester transfer protein (CETP) catalyses the transfer of cholesteryl ester from HDL to other lipoproteins and therefore might influence HDL levels. Using monoclonal antibodies, we show that CETP is absent in two Japanese siblings who have markedly increased and enlarged HDL. Furthermore, they are homozygous for a point mutation in the 5'-splice donor site of intron 14 of the gene for CETP, a change that is incompatible with normal splicing of pre-messenger RNA. The results indicate that the family has an inherited deficiency of CETP due to a gene splicing defect, and illustrate the key role that CETP has in human HDL metabolism.
J. Biol. Chem. 262, 2275-2282 (1987)[PubMed:3818596]
The cholesteryl ester transfer protein (CETP) binds to plasma lipoproteins and promotes transfer of cholesteryl esters between the lipoproteins. CETP has been purified 55,000-fold, with a 27% recovery of activity, from the d greater than 1.21 g/ml fraction of human plasma. In the final purification step, partially purified CETP is incubated with a synthetic lipid emulsion consisting of phosphatidylcholine, triglyceride, and fatty acid, and the bound activity, which elutes in the void volume, is separated from nonbound proteins by gel filtration on Sepharose 4B. Sodium dodecyl sulfate-gel analysis of fractions containing bound activity shows the presence of a single protein with an apparent Mr of 74,000. Inclusion of fatty acid in this emulsion was required to prevent the binding of a contaminant protein. However, incubation of CEPT with fatty acid emulsions containing lipid peroxides resulted in substantial inactivation and covalent degradation of the 74-kDa protein. This could be prevented by the inclusion of antioxidants during preparation of the emulsion. Solvent extraction of emulsion-bound CEPT gave a delipidated, active preparation. Purified IgG from a rabbit immunized with the 74-kDa protein completely removed activity from partially purified fractions. Amino acid analysis of the purified protein showed it to contain an unusually high content (45%) of nonpolar residues; the calculated hydrophobicity was greater than that of any other plasma apolipoprotein. These results show human CETP to be a unique plasma apolipoprotein with an apparent Mr of 74,000 which is hydrophobic, self-associating, and susceptible to covalent degradation by lipid peroxides.
The directed movement of lipids into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. Lipids are compounds soluble in an organic solvent but not, or sparingly, in an aqueous solvent.
J. Biol. Chem. 262, 2275-2282 (1987)[PubMed:3818596]
The cholesteryl ester transfer protein (CETP) binds to plasma lipoproteins and promotes transfer of cholesteryl esters between the lipoproteins. CETP has been purified 55,000-fold, with a 27% recovery of activity, from the d greater than 1.21 g/ml fraction of human plasma. In the final purification step, partially purified CETP is incubated with a synthetic lipid emulsion consisting of phosphatidylcholine, triglyceride, and fatty acid, and the bound activity, which elutes in the void volume, is separated from nonbound proteins by gel filtration on Sepharose 4B. Sodium dodecyl sulfate-gel analysis of fractions containing bound activity shows the presence of a single protein with an apparent Mr of 74,000. Inclusion of fatty acid in this emulsion was required to prevent the binding of a contaminant protein. However, incubation of CEPT with fatty acid emulsions containing lipid peroxides resulted in substantial inactivation and covalent degradation of the 74-kDa protein. This could be prevented by the inclusion of antioxidants during preparation of the emulsion. Solvent extraction of emulsion-bound CEPT gave a delipidated, active preparation. Purified IgG from a rabbit immunized with the 74-kDa protein completely removed activity from partially purified fractions. Amino acid analysis of the purified protein showed it to contain an unusually high content (45%) of nonpolar residues; the calculated hydrophobicity was greater than that of any other plasma apolipoprotein. These results show human CETP to be a unique plasma apolipoprotein with an apparent Mr of 74,000 which is hydrophobic, self-associating, and susceptible to covalent degradation by lipid peroxides.
The acquisition, loss or modification of a protein or lipid within a low-density lipoprotein particle, including the hydrolysis of triglyceride by hepatic lipase, with the subsequent loss of free fatty acid, and the transfer of cholesterol esters from LDL to a triglyceride-rich lipoprotein particle by cholesteryl ester transfer protein (CETP), with the simultaneous transfer of triglyceride to LDL.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
Negative regulation of macrophage derived foam cell differentiationdefinition[GO:0010745]
Any process that decreases the rate, frequency or extent of macrophage derived foam cell differentiation. Macrophage derived foam cell differentiation is the process in which a macrophage acquires the specialized features of a foam cell. A foam cell is a type of cell containing lipids in small vacuoles and typically seen in atherosclerotic lesions, as well as other conditions.
Genetic deficiency or inhibition of cholesteryl ester transfer protein (CETP) leads to a marked increase in plasma levels of large HDL-2 particles. However, there is concern that such particles may be dysfunctional in terms of their ability to promote cholesterol efflux from macrophages. Recently, the ATP-binding cassette transporter ABCG1, a macrophage liver X receptor (LXR) target, has been shown to stimulate cholesterol efflux to HDL. We have assessed the ability of HDL from subjects with homozygous deficiency of CETP (CETP-D) to promote cholesterol efflux from macrophages and have evaluated the role of ABCG1 and other factors in this process. CETP-D HDL-2 caused a 2- to 3-fold stimulation of net cholesterol efflux compared with control HDL-2 in LXR-activated macrophages, due primarily to an increase in lecithin:cholesterol acyltransferase-mediated (LCAT-mediated) cholesteryl ester formation in media. Genetic knockdown or overexpression of ABCG1 showed that increased cholesterol efflux to CETP-D HDL was ABCG1 dependent. LCAT and apoE contents of CETP-D HDL-2 were markedly increased compared with control HDL-2, and increased cholesterol esterification activity resided within the apoE-HDL fraction. Thus, CETP-D HDL has enhanced ability to promote cholesterol efflux from foam cells in an ABCG1-dependent pathway due to an increased content of LCAT and apoE.
The chemical reactions and pathways involving phosphatidylcholines, any of a class of glycerophospholipids in which the phosphatidyl group is esterified to the hydroxyl group of choline. They are important constituents of cell membranes.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
The directed movement of phospholipids into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. Phospholipids are any lipids containing phosphoric acid as a mono- or diester.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
Any process that modulates the frequency, rate or extent of cholesterol efflux. Cholesterol efflux is the directed movement of cholesterol, cholest-5-en-3-beta-ol, out of a cell or organelle.
Genetic deficiency or inhibition of cholesteryl ester transfer protein (CETP) leads to a marked increase in plasma levels of large HDL-2 particles. However, there is concern that such particles may be dysfunctional in terms of their ability to promote cholesterol efflux from macrophages. Recently, the ATP-binding cassette transporter ABCG1, a macrophage liver X receptor (LXR) target, has been shown to stimulate cholesterol efflux to HDL. We have assessed the ability of HDL from subjects with homozygous deficiency of CETP (CETP-D) to promote cholesterol efflux from macrophages and have evaluated the role of ABCG1 and other factors in this process. CETP-D HDL-2 caused a 2- to 3-fold stimulation of net cholesterol efflux compared with control HDL-2 in LXR-activated macrophages, due primarily to an increase in lecithin:cholesterol acyltransferase-mediated (LCAT-mediated) cholesteryl ester formation in media. Genetic knockdown or overexpression of ABCG1 showed that increased cholesterol efflux to CETP-D HDL was ABCG1 dependent. LCAT and apoE contents of CETP-D HDL-2 were markedly increased compared with control HDL-2, and increased cholesterol esterification activity resided within the apoE-HDL fraction. Thus, CETP-D HDL has enhanced ability to promote cholesterol efflux from foam cells in an ABCG1-dependent pathway due to an increased content of LCAT and apoE.
Lecithin:cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) are responsible for the esterification of cell-derived cholesterol and for the transfer of newly synthesized cholesteryl esters (CE) from HDL to apoB-containing lipoproteins in human plasma. LCAT and CETP are also crucial factors in HDL remodeling, a process by which HDL particles with a high capacity for cell cholesterol uptake are generated in plasma. In the present study, cholesterol esterification and transfer were evaluated in 60 patients with isolated hypercholesterolemia (HC, n = 20) and isolated (HTG, n = 20) or mixed hypertriglyceridemia (MHTG, n = 20) and in 20 normolipidemic healthy individuals (NL). Cholesterol esterification rate (CER) and net CE transfer rate (CETR) were measured in whole plasma. LCAT and CETP concentrations were determined by specific immunoassays. HDL remodeling was analyzed by monitoring changes in HDL particle size distribution during incubation of whole plasma at 37 degrees C. Mean CER and CETR were 48% and 73% higher, respectively, in hypertriglyceridemic (HTG + MHTG) versus normotriglyceridemic individuals. HDL remodeling was also significantly accelerated in plasma from hypertriglyceridemic patients. Strong positive correlations were found in the total sample between plasma and VLDL triglyceride levels and CER (r = .722 and r = .642, respectively), CETR (r = .510 and r = .491, respectively), and HDL remodeling (r = .625 and r = .620, respectively). No differences in plasma LCAT and CETP concentrations were found among the various groups except for a tendency toward higher CETP levels in hypercholesterolemic patients (+51% in MHTG and +20% in HC) versus control subjects (NL). By stepwise regression analysis, VLDL triglyceride level was the sole significant predictor of CER and CETR and contributed significantly together with baseline HDL particle distribution to HDL remodeling. These results indicate that plasma triglyceride level is a major factor in the regulation of cholesterol esterification/transfer and HDL remodeling in human plasma, whereas LCAT/CETP concentrations play a minor role in the modulation of reverse cholesterol transport.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
The chemical reactions and pathways involving triglyceride, any triester of glycerol. The three fatty acid residues may all be the same or differ in any permutation. Triglycerides are important components of plant oils, animal fats and animal plasma lipoproteins.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
The acquisition, loss or modification of a protein or lipid within a very-low-density lipoprotein particle, including the hydrolysis of triglyceride by hepatic lipase or lipoprotein lipase and the subsequent loss of free fatty acid.
J. Biol. Chem. 263, 5150-5157 (1988)[PubMed:2833496]
The plasma cholesteryl ester-transfer protein (CETP, Mr 74,000) promotes exchange of both neutral lipids and phospholipids (phosphatidylcholine, PC) between lipoproteins. To investigate the mechanism of facilitated lipid transfer, CETP was incubated with unilamellar egg PC vesicles containing small amounts of cholesteryl ester (CE) or triglyceride, and then analyzed by gel filtration chromatography. There was rapid transfer of radiolabeled CE or triglyceride and PC from vesicles to CETP. The CETP with bound lipids was isolated and incubated with low density lipoproteins (LDL), resulting in transfer of the lipids to LDL. The CETP bound up to 0.9 mol of CE or 0.2 mol of triglyceride and 11 mol of PC/mol of CETP. para-Chloromercuriphenylsulfonate, an inhibitor of CE and triglyceride transfer, was found to decrease the binding of radiolabeled CE and triglyceride by CETP. Under various conditions the CETP eluted either as an apparent monomer with bound lipid (Mr 75,000-93,000), or in complexes with vesicles. The distribution of CETP between these two states was influenced by the presence of apoA-I or albumin, incubation time, vesicle/CETP ratio, and buffer pH and ionic strength. The results indicate that the CETP has binding sites for CE, triglyceride, and PC which readily equilibrate with lipoprotein lipids and suggest that CETP can act as a carrier of lipid between lipoproteins.
Protein which participates in the biochemical reactions where cholesterol is involved, including transport. Cholesterol is the major sterol of higher animals and an important component of cell membranes, especially of the plasma membrane.
Protein involved in the biochemical reactions of lipids. Lipids are a diverse class of compounds which are insoluble in water but soluble in organic solvents. They include fats, oils, triacylglycerols, fatty acids, glycolipids, phospholipids and steroids.
Protein involved in the transport of lipids, a diverse class of compounds which are insoluble in water but soluble in organic solvents. They include fats, oils, triacylglycerols, fatty acids, glycolipids, phospholipids and steroids.
Protein involved in the biochemical reactions of steroids. Steroids are a large group of complex tetracyclic lipids that consist of a 17- carbon-ring system. Examples are bile acids, sterols, various hormones and saponins.
Protein involved in the transport of a molecule (metabolite, protein, etc), a ion or an electron across cell membranes, inside the cell or in a tissue fluid.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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