Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Not the mature 56 kDa lipoprotein lipase protein but a 37 kDa protein co-purifying with the lipase mediates the binding of low density lipoproteins to J774 macrophages.

ABSTRACT: Lipoprotein lipase (LPL) purified from bovine milk showed variable abilities to stimulate the binding of low density lipoprotein (LDL) to J774 macrophages. The presence of a 37 kDa protein in the LPL sample seemed to be of importance for its stimulatory capacity. In order to investigate this, we isolated LPL from bovine milk via heparin Sepharose chromatography using a continuous salt gradient. Fractions containing the 37 kDa protein (as shown by SDS/PAGE under reducing conditions) eluted first from the column, followed by the 56 kDa LPL protein. The LPL enzymatic activity co-eluted with the 56 kDa protein, whereas the amount of 37 kDa protein fully paralleled the stimulatory effect on the binding of LDL to J774 cells. Samples not containing the 37 kDa protein were far less effective in stimulating the binding. Western blotting using a monoclonal antibody 5D2 against amino acids 396-405 in the carboxy-terminal domain of LPL, showed that the 37 kDa protein may be the C-terminal domain of LPL, presumably generated by proteolytic degradation of the mature LPL protein by milk proteases during its isolation. Furthermore, the functional mass of LPL for stimulation of the binding of LDL, as determined by radiation inactivation, was shown to be 30.9+/-1.8 kDa. We therefore suggest that cleavage of LPL at protease-sensitive sites causes a conformational change, generating an LPL protein which is more effective in mediating the binding and uptake of lipoproteins by cells.

SUBMITTER: Hendriks WL

PROVIDER: S-EPMC1219203 | biostudies-other | 1998 Mar

REPOSITORIES: biostudies-other

ACCESS DATA

Json Xml

Similar Datasets

Lipoprotein lipase bound to apolipoprotein B lipoproteins accelerates clearance of postprandial lipoproteins in humans.

Project description:Experiments in cells and animal models show that lipoprotein lipase (LpL) bound to apolipoprotein (apo)B lipoproteins enhances their uptake by receptor mediated pathways. It is unknown whether this pathway is important in humans.ApoB lipoproteins with LpL were isolated from normal subjects after oral fat loading by immunoaffinity chromatography and were further separated into apoB100 and apoB48 lipoproteins. Postprandially, apoB lipoproteins with LpL had significantly greater increases (4- to 10-fold) and faster rates of clearance (5- to 8-fold) percentage-wise than those without LpL. apoB lipoproteins with LpL had enhanced clearance regardless of whether they also contained apoE. LpL was particularly important for the clearance of apoB48 lipoproteins, of which 25% (range, 11% to 31%) could be removed from circulation together with LpL during the postprandial state. apoB lipoproteins with LpL were larger in size and were enriched in triglyceride, cholesterol, and apoE compared with those without LpL. However, neither size nor apoE content explained the faster clearance rates of LpL-containing lipoproteins.Plasma LpL may act like an apolipoprotein to enhance the clearance of apoB lipoproteins in humans, a mechanism particularly important for intestinal lipoproteins in the postprandial state.

| S-EPMC3219220 | biostudies-literature

Lipoprotein lipase stimulates the binding and uptake of moderately oxidized low-density lipoprotein by J774 macrophages.

Project description:Lipoprotein lipase (LPL) stimulates the uptake of low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL) in different cell types, including macrophages, through bridging of LPL between lipoproteins and extracellular heparan sulphate proteoglycans (HSPG). Because macrophages produce LPL and because modified lipoproteins are present in the arterial wall in vivo, we wondered whether LPL also enhances the uptake of oxidized LDL by J774 macrophages. LDL samples with different degrees of oxidation, as evaluated by relative electrophoretic mobility (REM) as compared with native LDL are used as well as native and acetylated LDL. Addition of 5 microg/ml LPL to the J774 cell culture medium stimulated the binding of both native LDL and moderately oxidized LDL (REM < 3.5) 50-100-fold, and their uptake was stimulated approx. 20-fold. The LPL-mediated binding of native LDL and moderately oxidized LDL was dose-dependent. Preincubation of the cells with heparinase (2.4 units/ml) inhibited the stimulatory effect of LPL, indicating that this LPL-mediated stimulation was due to bridging between the lipoproteins and HSPG. The binding to J774 macrophages of severely oxidized LDL (REM=4.3) was stimulated less than 3-fold by LPL, whereas its uptake was not stimulated significantly. The binding and uptake of acetylated LDL (AcLDL) were not stimulated by LPL, although the LPL-molecule itself does bind to AcLDL. Measurements of the cellular lipid content showed that addition of LPL also stimulated the accumulation in the cells of cholesteryl ester derived from both native LDL and moderately oxidized LDL in a dose-dependent manner. We conclude that our results present experimental evidence for the hypothesis that LPL serves as an atherogenic component in the vessel wall.

| S-EPMC1217086 | biostudies-other

The 37/67 kDa laminin receptor (LR) inhibitor, NSC47924, affects 37/67 kDa LR cell surface localization and interaction with the cellular prion protein.

Project description:The 37/67 kDa laminin receptor (LR) is a non-integrin protein, which binds both laminin-1 of the extracellular matrix and prion proteins, that hold a central role in prion diseases. The 37/67 kDa LR has been identified as interactor for the prion protein (PrP(C)) and to be required for pathological PrP (PrP(Sc)) propagation in scrapie-infected neuronal cells, leading to the possibility that 37/67 kDa LR-PrP(C) interaction is related to the pathogenesis of prion diseases. A relationship between 37/67 kDa LR and PrP(C) in the presence of specific LR inhibitor compounds has not been investigated yet. We have characterized the trafficking of 37/67 kDa LR in both neuronal and non-neuronal cells, finding the receptor on the cell surface and nuclei, and identified the 67 kDa LR as the almost exclusive isoform interacting with PrP(C). Here, we show that the treatment with the 37/67 kDa LR inhibitor, NSC47924, affects both the direct 37/67 kDa LR-PrP(C) interaction in vitro and the formation of the immunocomplex in live cells, inducing a progressive internalization of 37/67 kDa LR and stabilization of PrP(C) on the cell surface. These data reveal NSC47924 as a useful tool to regulate PrP(C) and 37/67 kDa LR trafficking and degradation, representing a novel small molecule to be tested against prion diseases.

| S-EPMC4829897 | biostudies-literature

Chimeric Avidin--NMR structure and dynamics of a 56 kDa homotetrameric thermostable protein.

Project description:Chimeric avidin (ChiAVD) is a product of rational protein engineering remarkably resistant to heat and harsh conditions. In quest of the fundamentals behind factors affecting stability we have elucidated the solution NMR spectroscopic structure of the biotin-bound form of ChiAVD and characterized the protein dynamics through 15N relaxation and hydrogen/deuterium (H/D) exchange of this and the biotin-free form. To surmount the challenges arising from the very large size of the protein for NMR spectroscopy, we took advantage of its high thermostability. Conventional triple resonance experiments for fully protonated proteins combined with methyl-detection optimized experiments acquired at 58°C were adequate for the structure determination of this 56 kDa protein. The model-free parameters derived from the 15N relaxation data reveal a remarkably rigid protein at 58°C in both the biotin-bound and the free forms. The H/D exchange experiments indicate a notable increase in hydrogen protection upon biotin binding.

| S-EPMC4069078 | biostudies-literature

Lipolysis of triglyceride-rich lipoproteins generates PPAR ligands: evidence for an antiinflammatory role for lipoprotein lipase.

Project description:Increased levels of triglyceride-rich lipoproteins provoke lipid accumulation in the artery wall, triggering early inflammatory responses central to atherosclerosis like endothelial adhesion molecule expression. The endogenous mechanisms limiting such reactions remain poorly defined. Lipoprotein lipase (LPL) plays a central role in lipid metabolism by hydrolyzing triglyceride rich lipoproteins and releasing fatty acids. We found that LPL treatment reversed tumor necrosis factor alpha and very low-density lipoprotein (VLDL)-stimulated endothelial vascular cell adhesion molecule 1 (VCAM1) induction and VCAM1 promoter responses, thus recapitulating effects reported with synthetic peroxisome proliferator-activated receptor (PPAR) agonists. In fact, these LPL effects on VCAM1 were absent in endothelial cells isolated from PPAR alpha-deficient mice. This finding suggests a novel antiinflammatory role for LPL. Further studies reveal specificity for PPAR activation through lipolysis in regards to lipoprotein substrate (VLDL >> LDL > HDL), PPAR isoform (PPAR alpha >> PPAR delta > PPAR gamma), and among fatty acid-releasing lipases. These PPAR responses required intact LPL catalytic activity. In vivo, transgenic mice overexpressing LPL had increased peroxisome proliferation, but not in the genetic absence of PPAR alpha. Although human plasma possesses minimal PPAR alpha activation despite containing abundant free fatty acids, marked PPAR alpha activation is seen with human plasma after LPL is added in vitro or systemically released in vivo. These data suggest a previously uncharacterized pathway in which the key lipolytic enzyme LPL can act on circulating lipoproteins to generate PPAR alpha ligands, providing a potentially important link between lipoprotein metabolism and distal PPAR alpha transcriptional effects.

| S-EPMC151409 | biostudies-literature

The ER-Associated Degradation Adapter Protein Sel1L Regulates Triglyceride Metabolism via Lipoprotein Lipase

Project description:Sel1L is an adaptor protein for the E3 ligase Hrd1 in the endoplasmic reticulum-associated degradation (ERAD), but its physiological role in a cell-type-specific manner remains unclear. Here we show that mice with adipocyte-specific Sel1L deficiency are resistant to diet-induced obesity and exhibit postprandial hypertriglyceridemia. Mechanistically, our data demonstrate a critical requirement of Sel1L for the secretion of lipoprotein lipase (LPL), independently of its role in Hrd1-mediated ERAD and ER homeostasis. Further biochemical analyses revealed that Sel1L physically interacts and stabilizes the LPL maturation complex consisted of LPL and lipase-maturation factor 1 (LMF1). In the absence of Sel1L, LPL is retained in the ER and prone to the formation of protein aggregates, which are degraded by autophagy-mediated degradation. The Sel1L-mediated control of LPL secretion is seen in other LPL-expressing cell types as well such as cardiac muscle and macrophages. Thus, our study reports a novel role of Sel1L in LPL secretion and systemic lipid metabolism. Sel1Lflox/flox mice were crossed with adiponectin promoter driven Cre mice to create adipose tissue-specific Sel1L-/- mice. Male wildtype C57Bl/6 mice and adipose tissue-specific Sel1l-/- mice were fed a high fat diet (Research Diets D12492) for 5 weeks. Adipose tissue was excised and used for microarray analysis.

2015-05-18 | E-GEOD-56918 | biostudies-arrayexpress

The ER-Associated Degradation Adapter Protein Sel1L Regulates Triglyceride Metabolism via Lipoprotein Lipase

2015-05-18 | GSE56918 | GEO

High-density lipoprotein subpopulation profiles in lipoprotein lipase and hepatic lipase deficiency.

Project description:Background and aimsOur aim was to gain insight into the role that lipoprotein lipase (LPL) and hepatic lipase (HL) plays in HDL metabolism and to better understand LPL- and HL-deficiency states.MethodsWe examined the apolipoprotein (apo) A-I-, A-II-, A-IV-, C-I-, C-III-, and E-containing HDL subpopulation profiles, assessed by native 2-dimensional gel-electrophoresis and immunoblotting, in 6 homozygous and 11 heterozygous LPL-deficient, 6 homozygous and 4 heterozygous HL-deficient, and 50 control subjects.ResultsLPL-deficient homozygotes had marked hypertriglyceridemia and significant decreases in LDL-C, HDL-C, and apoA-I. Their apoA-I-containing HDL subpopulation profile was shifted toward small HDL particles compared to controls. HL-deficient homozygotes had moderate hypertriglyceridemia, modest increases in LDL-C and HDL-C level, but normal apoA-I concentration. HL-deficient homozygotes had a unique distribution of apoA-I-containing HDL particles. The normally apoA-I:A-II, intermediate-size (α-2 and α-3) particles were significantly decreased, while the normally apoA-I only (very large α-1, small α-4, and very small preβ-1) particles were significantly elevated. In contrast to control subjects, the very large α-1 particles of HL-deficient homozygotes were enriched in apoA-II. Homozygous LPL- and HL-deficient subjects also had abnormal distributions of apo C-I, C-III, and E in HDL particles. Values for all measured parameters in LPL- and HL-deficient heterozygotes were closer to values measured in controls than in homozygotes.ConclusionsOur data are consistent with the concept that LPL is important for the maturation of small discoidal HDL particles into large spherical HDL particles, while HL is important for HDL remodeling of very large HDL particles into intermediate-size HDL particles.

| S-EPMC5064856 | biostudies-literature

Phylogenetic analysis of the 56-kDa type-specific protein genes of Orientia tsutsugamushi in Central Korea.

Project description:There are several antigenic variants of Orientia tsutsugamushi. The 56-kDa type-specific antigen (TSA) is responsible for the antigenic variation. Nucleotide sequences of the 56-kDa TSA obtained from 44 eschar samples of Korean scrub typhus patients and from 40 representative strains retrieved from the GenBank database were analyzed phylogenetically. Clinical patient data were assessed based on the genotyping results. Of the 44 nucleotide sequences, 32 (72.7%) clustered with the Boryong genotype, which is the major genotype in Korea. Eleven nucleotide sequences (25%) clustered with the Kawasaki genotype, not identified in Korea until 2010. One nucleotide sequence was consistent with the Karp genotype. The clinical course of the patients infected with each genotype showed no differences. Diagnostic performance of the immunofluorescence assay (IFA) using the 56-kDa TSA from Gilliam, Karp and Boryong as test antigens were not different for the Boryong and Kawasaki genotypes. Although Boryong is still the predominant genotype, the results suggest that Kawasaki genotype is quite prevalent in Chungbuk province of Korea.

| S-EPMC3492664 | biostudies-literature

Phylogenetic analysis of the 56 kDa protein genes of Orientia tsutsugamushi in Southwest Area of Korea.

Project description:This study was conducted to determine which genotypes were present in southwestern Korea. Nested polymerase chain reaction (PCR) and DNA sequence analysis targeting the Orientia tsutsugamushi-specific 56-kDa protein gene was performed with samples of blood and eschar. Of the 69 PCR-positive samples, 61 clustered with the Boryong previously isolated in Korea. CUH 4-6 had sequence homology of 100% with Kato, and CUH 4-3 had homology of 99.8% with Kato and formed the Kato cluster. CUH 4-57, CUH 4-31, CUH 4-142, and CUH 4-324 formed a Kawasaki cluster. CUH 4-271 had sequence homology of 100% with Jecheon and formed a Karp cluster. CUH 4-117 had homology of 99.8% with Neimeng-65, and Gilliam cluster. The most common genotype of O. tsutsugamushi in the southwestern part of Korea is the Boryong genotype. We also identified O. tsutsugamushi of the Kato, Neimeng-65 and Kawasaki genotypes, which had not been identified before in Korea.

| S-EPMC3029177 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data