1
|
Gordon SM, Li H, Zhu X, Shah AS, Lu LJ, Davidson WS. A comparison of the mouse and human lipoproteome: suitability of the mouse model for studies of human lipoproteins. J Proteome Res 2015; 14:2686-95. [PMID: 25894274 PMCID: PMC4712022 DOI: 10.1021/acs.jproteome.5b00213] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Plasma levels of low density lipoproteins (LDL) and high density lipoproteins (HDL) exhibit opposing associations with cardiovascular disease in human populations and mouse models have been heavily used to derive a mechanistic understanding of these relationships. In humans, recent mass spectrometry studies have revealed that the plasma lipoproteome is significantly more complex than originally appreciated. This is particularly true for HDL which contains some 90 distinct proteins, a majority of which play functional roles that go beyond those expected for simple lipid transport. Unfortunately, the mouse lipoproteome remains largely uncharacterized-a significant gap given the heavy reliance on the model. Using a gel filtration chromatography and mass spectrometry analysis that targets phospholipid-bound plasma proteins, we compared the mouse lipoproteome and its size distribution to a previous, identical human analysis. We identified 113 lipid associated proteins in the mouse. In general, the protein diversity in the LDL and HDL size ranges was similar in mice versus humans, though some distinct differences were noted. For the majority of proteins, the size distributions, that is, whether a given protein was associated with large versus small HDL particles, for example, were also similar between species. Again, however, there were clear differences exhibited by a minority of proteins that may reflect metabolic differences between species. Finally, by correlating the lipid and protein size profiles, we identified five proteins that closely track with the major HDL protein, apolipoprotein A-I across both species. Thus, mice have most of the minor proteins identified in human lipoproteins that play key roles in inflammation, innate immunity, proteolysis and its inhibition, and vitamin transport. This provides support for the continued use of the mouse as a model for many aspects of human lipoprotein metabolism.
Collapse
Affiliation(s)
- Scott M. Gordon
- Center for Lipid and Arteriosclerosis Science, Department of Pathology and Laboratory Medicine, University of Cincinnati, 2120 East Galbraith Road, Cincinnati, Ohio 45237-0507, United States
| | - Hailong Li
- Division of Biomedical Informatics, Cincinnati Children’s Hospital Research Foundation, 3333 Burnet Avenue, MLC 7024, Cincinnati, Ohio 45229-3039, United States
| | - Xiaoting Zhu
- Division of Biomedical Informatics, Cincinnati Children’s Hospital Research Foundation, 3333 Burnet Avenue, MLC 7024, Cincinnati, Ohio 45229-3039, United States
| | - Amy S. Shah
- Department of Pediatrics, Cincinnati Children’s Hospital Research Foundation, 3333 Burnet Avenue, MLC 7012, Cincinnati, Ohio 45229-3039, United States
| | - L. Jason Lu
- Division of Biomedical Informatics, Cincinnati Children’s Hospital Research Foundation, 3333 Burnet Avenue, MLC 7024, Cincinnati, Ohio 45229-3039, United States
| | - W. Sean Davidson
- Center for Lipid and Arteriosclerosis Science, Department of Pathology and Laboratory Medicine, University of Cincinnati, 2120 East Galbraith Road, Cincinnati, Ohio 45237-0507, United States
| |
Collapse
|
2
|
Engberg AE, Rosengren-Holmberg JP, Chen H, Nilsson B, Lambris JD, Nicholls IA, Ekdahl KN. Blood protein-polymer adsorption: implications for understanding complement-mediated hemoincompatibility. J Biomed Mater Res A 2011; 97:74-84. [PMID: 21319295 DOI: 10.1002/jbm.a.33030] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Revised: 10/11/2010] [Accepted: 12/07/2010] [Indexed: 12/15/2022]
Abstract
The aim of this study was to create polymeric materials with known properties to study the preconditions for complement activation. Initially, 22 polymers were screened for complement activating capacity. Based on these results, six polymers (P1-P6) were characterized regarding physico-chemical parameters, for example, composition, surface area, pore size, and protein adsorption from human EDTA-plasma. P2, P4, and reference particles of polystyrene and polyvinyl chloride, were hydrophobic, bound low levels of protein and were poor complement activators. Their accessible surface was limited to protein adsorption in that they had pore diameters smaller than most plasma proteins. P1 and P3 were negatively charged and adsorbed IgG and C1q. A 10-fold difference in complement activation was attributed to the fact that P3 but not P1 bound high amounts of C1-inhibitor. The hydrophobic P5 and P6 were low complement activators. They selectively bound apolipoproteins AI and AIV (and vitronectin), which probably limited the binding of complement activators to the surface. We demonstrate the usefulness of the modus operandi to use a high-throughput procedure to synthesize a great number of novel substances, assay their physico-chemical properties with the aim to study the relationship between the initial protein coat on a surface and subsequent biological events. Data obtained from the six polymers characterized here, suggest that a complement-resistant surface should be hydrophobic, uncharged, and have a small available surface, accomplished by nanostructured topography. Additional attenuation of complement can be achieved by selective enrichment of inert proteins and inhibitors.
Collapse
Affiliation(s)
- Anna E Engberg
- School of Natural Sciences, Linnaeus University, Kalmar SE-391 82, Sweden
| | | | | | | | | | | | | |
Collapse
|
3
|
Tubb MR, Silva RAGD, Fang J, Tso P, Davidson WS. A three-dimensional homology model of lipid-free apolipoprotein A-IV using cross-linking and mass spectrometry. J Biol Chem 2008; 283:17314-23. [PMID: 18430727 PMCID: PMC2427326 DOI: 10.1074/jbc.m800036200] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 04/10/2008] [Indexed: 11/06/2022] Open
Abstract
Human apolipoprotein A-IV (apoA-IV) is a 46-kDa exchangeable plasma protein with many proposed functions. It is involved in chylomicron assembly and secretion, protection from atherosclerosis through a variety of mechanisms, and inhibition of food intake. There is little structural basis for these proposed functions due to the lack of a solved three-dimensional structure of the protein by x-ray crystallography or NMR. Based on previous studies, we hypothesized that lipid-free apoA-IV exists in a helical bundle, like other apolipoprotein family members and that regions near the N and C termini may interact. Utilizing a homobifunctional lysine cross-linking agent, we identified 21 intramolecular cross-links by mass spectrometry. These cross-links were used to constrain the building of a sequence threaded homology model using the I-TASSER server. Our results indicate that lipid-free apoA-IV does indeed exist as a complex helical bundle with the N and C termini in close proximity. This first structural model of lipid-free apoA-IV should prove useful for designing studies aimed at understanding how apoA-IV interacts with lipids and possibly with unknown protein partners.
Collapse
Affiliation(s)
- Matthew R Tubb
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237, USA
| | | | | | | | | |
Collapse
|
4
|
Pearson K, Tubb MR, Tanaka M, Zhang XQ, Tso P, Weinberg RB, Davidson WS. Specific Sequences in the N and C Termini of Apolipoprotein A-IV Modulate Its Conformation and Lipid Association. J Biol Chem 2005; 280:38576-82. [PMID: 16159879 DOI: 10.1074/jbc.m506802200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Apolipoprotein (apoA-IV) is a 376-residue exchangeable apolipoprotein that may play a number of important roles in lipid metabolism, including chylomicron assembly, reverse cholesterol transport, and appetite regulation. In vivo, apoA-IV exists in both lipid-poor and lipid-associated forms, and the balance between these states may determine its function. We examined the structural elements that modulate apoA-IV lipid binding by producing a series of deletion mutants and determining their ability to interact with phospholipid liposomes. We found that the deletion of residues 333-343 strongly increased the lipid association rate versus native apoA-IV. Additional mutagenesis revealed that two phenylalanine residues at positions 334 and 335 mediated this lipid binding inhibitory effect. We also observed that residues 11-20 in the N terminus were required for the enhanced lipid affinity induced by deletion of the C-terminal sequence. We propose a structural model in which these sequences can modulate the conformation and lipid affinity of apoA-IV.
Collapse
Affiliation(s)
- Kevin Pearson
- Department of Pathology and Laboratory Medicine, The University of Cincinnati, Cincinnati, Ohio 45237-0507, USA
| | | | | | | | | | | | | |
Collapse
|
5
|
Bergström J, Murphy CL, Weiss DT, Solomon A, Sletten K, Hellman U, Westermark P. Two different types of amyloid deposits--apolipoprotein A-IV and transthyretin--in a patient with systemic amyloidosis. J Transl Med 2004; 84:981-8. [PMID: 15146166 DOI: 10.1038/labinvest.3700124] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Certain forms of systemic amyloidosis have been associated with the pathologic deposition as fibrils of three different apolipoprotein-related proteins--apolipoprotein A-I, apolipoprotein A-II, and serum amyloid A. We have previously reported (Bergström et al, Biochem Biophys Res Commun 2001;285:903-908) that amyloid fibrils extracted from the heart of an elderly male with senile systemic amyloidosis contained, in addition to wild-type transthyretin-related molecules, an N-terminal fragment of yet a fourth apolipoprotein--apolipoprotein A-IV (apoA-IV). We now provide the results of our studies that have established the complete amino-acid sequence of this approximately 70-residue component and, additionally, have shown this protein to be the product of an unmutated apoA-IV gene. Notably, the apoA-IV and transthyretin fibrils were not codeposited but, rather, had anatomically distinct patterns of distribution within the heart and other organs, as evidenced immunohistochemically, by variation in the ultra structural morphology and by differences in the intensity of Congo red birefringence. These findings provide the first conclusive evidence that two separate forms of amyloid, each derived from a wild-type amyloidogenic precursor protein, were present in a patient with systemic amyloidosis.
Collapse
Affiliation(s)
- Joakim Bergström
- Department of Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | | | | | | | | | | | | |
Collapse
|
6
|
Weinberg RB, Anderson RA, Cook VR, Emmanuel F, Denèfle P, Tall AR, Steinmetz A. Interfacial exclusion pressure determines the ability of apolipoprotein A-IV truncation mutants to activate cholesterol ester transfer protein. J Biol Chem 2002; 277:21549-53. [PMID: 11940599 DOI: 10.1074/jbc.m202197200] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We used a panel of recombinant human apolipoprotein (apo) A-IV truncation mutants, in which pairs of 22-mer alpha-helices were sequentially deleted along the primary sequence, to examine the impact of protein structure and interfacial activity on the ability of apoA-IV to activate cholesterol ester transfer protein. Circular dichroism and fluorescence spectroscopy revealed that the secondary structure, conformation, and molecular stability of recombinant human apoA-IV were identical to the native protein. However, deletion of any of the alpha-helical domains in apoA-IV disrupted its tertiary structure and impaired its molecular stability. Surprisingly, determination of the water/phospholipid interfacial exclusion pressure of the apoA-IV truncation mutants revealed that, for most, deletion of amphipathic alpha-helical domains increased their affinity for phospholipid monolayers. All of the truncation mutants activated the transfer of fluorescent-labeled cholesterol esters between high and low density lipoproteins at a rate higher than native apoA-IV. There was a strong positive correlation (r = 0.790, p = 0.002) between the rate constant for cholesterol ester transfer and interfacial exclusion pressure. We conclude that molecular interfacial exclusion pressure, rather than specific helical domains, determines the degree to which apoA-IV, and likely other apolipoproteins, facilitate cholesterol ester transfer protein-mediated lipid exchange.
Collapse
Affiliation(s)
- Richard B Weinberg
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
| | | | | | | | | | | | | |
Collapse
|
7
|
Abstract
Apolipoprotein A-IV is a 46kDa glycoprotein that is synthesized by intestinal enterocytes and is incorporated into the surface of nascent chylomicrons. Considerable evidence suggests that apolipoprotein A-IV plays a role in intestinal lipid absorption and chylomicron assembly. We have proposed that polymorphisms that alter the interfacial behavior of apolipoprotein A-IV may modulate the physical properties and metabolic fate of plasma chylomicrons. Of the reported genetic polymorphisms of apolipoprotein A-IV, two, Q360H and T347S, are known to occur at high frequencies among the world populations. Biophysical studies have established that the Q360H isoprotein displays higher lipid affinity; conversely the T347S isoprotein is predicted to be less lipid avid. Recent studies have shown that the Q360H polymorphism is associated with increased postprandial hypertriglyceridemia, a reduced low-density lipoprotein response to dietary cholesterol in the setting of a moderate fat intake, an increased high-density lipoprotein response to changes in total dietary fat content, and lower body mass and adiposity; the T347S polymorphism appears to confer the opposite effects. Studies on the diet-gene interactions of other apolipoprotein A-IV alleles are needed, as are studies on the interactions between apolipoprotein A-IV alleles and other apolipoprotein polymorphisms.
Collapse
Affiliation(s)
- Richard B Weinberg
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
| |
Collapse
|
8
|
|
9
|
Dynamic interfacial properties of human apolipoproteins A-IV and B-17 at the air/water and oil/water interface. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)33454-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
10
|
Fournier N, Atger V, Paul JL, Sturm M, Duverger N, Rothblat GH, Moatti N. Human ApoA-IV overexpression in transgenic mice induces cAMP-stimulated cholesterol efflux from J774 macrophages to whole serum. Arterioscler Thromb Vasc Biol 2000; 20:1283-92. [PMID: 10807744 DOI: 10.1161/01.atv.20.5.1283] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The role of apolipoprotein A-IV (apoA-IV) in lipoprotein metabolism has not been established. The aim of the present study was to investigate the role of apoA-IV in reverse cholesterol transport by comparing cellular cholesterol efflux to serum or serum fractions from control mice and from mice transgenic for human apoA-IV (HuA-IVTg mice). When Fu5AH hepatoma cells were used, the cholesterol efflux to serum from either control or transgenic mice was similar. When control J774 macrophage cells were used, a comparison of efflux to serum or lipoprotein-deficient serum (LPDS) failed to demonstrate any differences between control and transgenic mice. In contrast, when the J774 cells were pretreated with cAMP, there was a stimulation of efflux to whole serum or LPDS from HuA-IVTg mice. cAMP treatment had no effect on efflux to serum or LPDS from control mice. Pretreatment of the cells with cAMP did not enhance the efflux response to high density lipoprotein isolated from HuA-IVTg mouse serum. Our results suggest that apoA-IV, unassociated with high density lipoprotein particles, is responsible for enhanced cholesterol efflux. This study illustrates the role of lipid-free apolipoproteins in mediating cellular cholesterol efflux with use of a biological fluid and is potentially of physiological relevance, especially in apolipoprotein-rich extravascular fluids.
Collapse
Affiliation(s)
- N Fournier
- Laboratoire de Biochimie Appliquée (N.F., J.-L.P., M.S., N.M.), Faculté des Sciences Pharmaceutiques et Biologiques, Châtenay-Malabry, France.
| | | | | | | | | | | | | |
Collapse
|
11
|
Weinberg RB, Hopkins RA, Jones JB. Purification, isoform characterization, and quantitation of human apolipoprotein A-IV. Methods Enzymol 1996; 263:282-96. [PMID: 8749015 DOI: 10.1016/s0076-6879(96)63020-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- R B Weinberg
- Department of Internal Medicine, Bowman Gray School of Medicine, Winston-Salem, North Carolina 27157, USA
| | | | | |
Collapse
|
12
|
Weinberg RB. Identification of functional domains in the plasma apolipoproteins by analysis of inter-species sequence variability. J Lipid Res 1994. [DOI: 10.1016/s0022-2275(20)39927-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
13
|
Osada J, Pocoví M, Nicolosi RJ, Schaefer EJ, Ordovás JM. Nucleotide sequences of the Macaca fascicularis apolipoprotein C-III and A-IV genes. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1172:335-9. [PMID: 8448212 DOI: 10.1016/0167-4781(93)90226-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The cynomolgus monkey (Macaca fascicularis) apolipoprotein C-III and apolipoprotein A-IV genes have been isolated from a cynomolgus genomic DNA library and completely sequenced. These genes span 3.1 and 2.8 kilobases (kb), respectively. Apolipoprotein C-III gene is interrupted by three intervening sequences of 613, 135 and 1699 bp, respectively. The open reading frame encodes a protein of 99 amino acids which is 87% similar to the human. The cynomolgus mature protein is 79 residues long. Thr-74 is also present what might allow the formation of O-glycosidic linkage observed in the human protein. Apolipoprotein A-IV gene consist of two intervening sequences of 352 and 774 bp, respectively. The open reading frame encodes a protein of 429 amino acids which is 87% similar to the human. The cynomolgus mature protein is 409 residues long, 33 amino acids longer than the human, due to an insertion of 33 residues in its COOH-terminal region. This insertion is mainly composed of glutamine and glutamic acid, which confers cynomolgus apolipoprotein a higher hydrophilicity.
Collapse
Affiliation(s)
- J Osada
- Department of Clinical Sciences, University of Lowell, MA
| | | | | | | | | |
Collapse
|
14
|
Zannis VI, Kardassis D, Zanni EE. Genetic mutations affecting human lipoproteins, their receptors, and their enzymes. ADVANCES IN HUMAN GENETICS 1993; 21:145-319. [PMID: 8391199 DOI: 10.1007/978-1-4615-3010-7_3] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- V I Zannis
- Department of Medicine, Housman Medical Research Center, Boston University Medical Center, Massachusetts 02118
| | | | | |
Collapse
|
15
|
Adsorption of apolipoprotein A-IV to phospholipid monolayers spread at the air/water interface. A model for its labile binding to high density lipoproteins. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50376-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
16
|
Duverger N, Murry-Brelier A, Latta M, Reboul S, Castro G, Mayaux JF, Fruchart JC, Taylor JM, Steinmetz A, Denèfle P. Functional characterization of human recombinant apolipoprotein AIV produced in Escherichia coli. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 201:373-83. [PMID: 1935934 DOI: 10.1111/j.1432-1033.1991.tb16294.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Apolipoprotein AIV (apoAIV), a protein which is known to activate the enzyme lecithin: cholesterol acyltransferase, to bind to apoAI/AII receptor sites and also to promote cholesterol efflux from adipose cells, may play an important role in reverse cholesterol transport. In this report, the high-level production of soluble recombinant mature human apoAIV (isoform 1) in Escherichia coli is described. The recombinant protein was purified by avoiding lipid extraction or denaturation. The apoAIV preparation was analysed by its reactivity with antibodies raised against human apoAIV, SDS-gel electrophoresis, isoelectric focusing and N-terminal sequencing. The purified recombinant protein retains an extra methionine at the N-terminus. Purified recombinant and natural apoAIV proteins were indistinguishable with regard to their denaturation properties, thermo-stability or their fluorescence emission properties in the presence of various quantities of a quenching agent. Complexes of ApoAIV with L-alpha-dimyristoyl-glycerophosphocholine (Myr2GroPCho), glycerophosphocholine (GroPCho), or L-alpha-1-palmitoyl-2-oleoylglycerophosphocholine (PamOleGroPCho) prepared from plasmatic and from recombinant apoAIV proteins have similar densities as revealed by analytical centrifugation. They also share the same cofactor properties for the lecithin:cholesterol acyltransferase reaction. Recombinant apoAIV complex with Myr2GroPCho was also able to bind to the same apoAI/AII receptor sites and to promote cholesterol efflux to an equal extent from adipose cells. It is concluded that the recombinant protein is functionally identical to the plasmatic apoAIV and may therefore be very useful in helping to elucidate the physiological role of apoAIV.
Collapse
Affiliation(s)
- N Duverger
- SERLIA, Institut Pasteur de Lille, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Weinberg RB, Jordan MK, Steinmetz A. Distinctive structure and function of human apolipoprotein variant ApoA-IV-2. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(17)44762-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
18
|
Hayashi H, Nutting DF, Fujimoto K, Cardelli JA, Black D, Tso P. Transport of lipid and apolipoproteins A-I and A-IV in intestinal lymph of the rat. J Lipid Res 1990. [DOI: 10.1016/s0022-2275(20)42345-4] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
19
|
Weinberg RB, Jordan MK. Effects of phospholipid on the structure of human apolipoprotein A-IV. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39041-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
20
|
Weinberg RB, Patton CS. Binding of human apolipoprotein A-IV to human hepatocellular plasma membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1044:255-61. [PMID: 2344444 DOI: 10.1016/0005-2760(90)90311-k] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have investigated the binding of human apolipoprotein A-IV (apo A-IV) to human hepatocellular plasma membranes. Addition of increasing concentrations of radiolabeled apo A-IV to hepatic plasma membranes, in the presence and absence of a 25-fold excess of unlabeled apo A-IV, revealed saturation binding to the membranes with a KD of 154 nM and a binding maximum of 1.6 ng/microgram of membrane protein. The binding was temperature-insensitive, partially calcium-dependent, abolished when apo A-IV was denatured by guanidine hydrochloride or when the membranes were treated with Pronase and decreased when apo A-IV was incorporated into phospholipid/cholesterol proteoliposomes. In displacement studies using purified apolipoproteins and isolated lipoproteins, only unlabeled apo A-IV, apo A-I and high-density lipoproteins effectively competed with radiolabeled apo A-IV for membrane binding sites. We conclude that human apo A-IV exhibits high-affinity binding to isolated human hepatocellular plasma membranes which is saturable, reversible and specific.
Collapse
Affiliation(s)
- R B Weinberg
- Department of Medicine, University of Texas Health Science Center, Houston 77225
| | | |
Collapse
|
21
|
Evidence for high density lipoproteins as the major apolipoprotein A-IV-containing fraction in normal human serum. J Lipid Res 1989. [DOI: 10.1016/s0022-2275(20)38236-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|
22
|
Savion N, Gamliel A. Binding of apolipoprotein A-I and apolipoprotein A-IV to cultured bovine aortic endothelial cells. ARTERIOSCLEROSIS (DALLAS, TEX.) 1988; 8:178-86. [PMID: 3126727 DOI: 10.1161/01.atv.8.2.178] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Adult bovine aortic endothelial (ABAE) cells specifically bound 125I-labelled high density lipoprotein3 (125I-HDL3), and saturation of the binding was observed at a concentration of about 50 to 100 micrograms protein/ml. The binding of purified apolipoproteins (apo) A-I and A-IV to cultured ABAE cells and the correlation of this binding with the binding of HDL to the cells was studied. ABAE cells bound 125I-labelled apo A-I (125I-apo A-I) and after a 3-hour exposure to the ligand, most of the radioactivity (82%) was associated with the cell surface and was accessible for trypsinization. Saturation of 125I-apo A-I binding was observed at a concentration of 3 micrograms/ml; each cell possessed 1.38 X 10(5) high affinity binding sites (Kd = 2.04 X 10(-8) M). The cultures also bound 125I-labelled apo A-IV (125I-apo A-IV), and saturation of the binding was observed at a concentration of 2 micrograms/ml. Each cell possessed 5.4 X 10(4) high affinity binding sites for apo A-IV (Kd = 1.45 X 10(-8) M). Addition of either excess unlabelled apo A-I or excess unlabelled apo A-IV competed with the binding of both iodinated apo A-I and apo A-IV. It suggests that apo A-I and A-IV share the same binding site on endothelial cells. HDL also successfully competed with the binding of apo A-I and A-IV to ABAE cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- N Savion
- Maurice and Gabriela Goldschleger Eye Research Institute, Sheba Medical Center, Tel Hashomer, Israel
| | | |
Collapse
|
23
|
Gambert P, Lagrost L, Athias A, Bastiras S, Lallemant C. Role of apolipoprotein A IV in the interconversion of HDL subclasses. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1988; 243:263-9. [PMID: 3066182 DOI: 10.1007/978-1-4613-0733-4_33] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- P Gambert
- Laboratoire de Biochimie des Lipoprotéines, Faculté de Médecine, Hopital du Bocage, CHRU Dijon, France
| | | | | | | | | |
Collapse
|