Abstract
Two thirds of all MC2R mutations had a significant reduction in cell surface trafficking, even though MRAPalpha interacted with all mutants. Analysis of those mutant receptors that reached the cell surface indicated that four of six failed to signal, after stimulation with ACTH. CONCLUSION: The majo...
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PMID: 18840636
PDF is available here.
Abstract
We investigated the effects of HIV-1 transactivator of transcription (Tat), a protein released by virus-infected cells, on synapses between hippocampal neurons using an imaging-based assay that quantified clusters of the scaffolding protein postsynaptic density 95 fused to green fluorescent protein...
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PMID: 19036954
PDF is available here.
Abstract
We also observed significant association of APOEepsilon4 allele with degenerative dementias (P < 0.0001, OR =5.35). Our study suggests that LRPAP1-D and APOE E4 alleles significantly increase the susceptibility to degenerative dementias....
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PMID: 18721259
PDF is available here.
Abstract
The LDL receptor-related protein (originally called LRP, but now referred to as LRP1) is a large endocytic receptor that is widely expressed in several tissues. LRP1 is a member of the LDL receptor family that plays diverse roles in various biological processes including lipoprotein metabolism, degr...
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PMID: 18626063
PDF is available here.
Abstract
We conducted activity-based protein profiling experiments to discover novel proteases, involved in inflammation, that are regulated by LRP-1. We found that activated complement proteases accumulate at increased levels when LRP-1 is absent. Although LRP-1 functions as an endocytic receptor for C1r an...
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PMID: 18369152
PDF is available here.
Abstract
We have previously reported that elevated levels of tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) cause the death of RGCs in vivo and transformed retinal ganglion cells (RGC-5) in vitro. Yet, it is unclear how secreted proteases such as tPA and uPA directly cause RGCs'...
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PMID: 18243176
PDF is available here.
Abstract
We have used an evolutionary approach to determine whether gp96 interacts with receptors expressed on APCs and promotes MHC class I cross-presentation of minor histocompatibility Ags (H-Ags) to CTLs in the frog Xenopus. We show that in Xenopus gp96 binds the CD91 homolog at the surface of peritoneal...
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PMID: 18292541
PDF is available here.
Abstract
We test the hypothesis that low-pH induced unfolding of the RAP-D3 helical bundle facilitates dissociation of RAP-receptor complexes. First, variants of RAP-D3 resistant to low pH-induced unfolding were constructed by replacing interior histidine residues with phenylalanines. In contrast to native R...
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PMID: 18177055
PDF is available here.
Abstract
We investigated whether the thyroid phenotype in RAP knockout (KO) mice is associated with kidney alterations. By immunohistochemistry, we found that in RAP KO mice megalin expression on the apical membrane of renal proximal tubule cells was markedly reduced, with intracellular retention of the rece...
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PMID: 18296906
PDF is available here.
Abstract
Accumulating evidence suggests that metallothionein (MT)-I and -II promote neuronal survival and regeneration in vivo. The present study investigated the molecular mechanisms underlying the differentiation and survival-promoting effects of MT and a peptide modeled after MT, EmtinB. Both MT and Emtin...
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PMID: 17986228
PDF is available here.
Abstract
We demonstrate that the avidity of full-length RAP for LRP1 in vitro can be partially reconstituted by assembly of truncated, disulfide-linked RAP peptides on tetravalent streptavidin or bivalent immunoglobulin scaffolds. The peptide complex with streptavidin shows pronounced hepatotropism in vivo,...
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PMID: 17963731
PDF is available here.
Abstract
The ACE and the LRPAP1 gene insertion-deletion polymorphisms were determined in 133 healthy individuals sampled from Ouangolodougou, a village located in northern Ivory Coast. No sex differences were found in ACE and LRPAP1 gene frequencies. The ACE insertion and deletion alleles had frequencies of...
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PMID: 18494379
PDF is available here.
Abstract
We studied the entire coding sequence of RAP in genomic DNA samples from 18 patients with primary hypothyroidism not due to thyroid autoimmunity or dysgenesis. The control group included 21 subjects with no evidence of thyroid alterations. Eleven different polymorphisms with amino-acid substitution...
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PMID: 18075286
PDF is available here.
Abstract
We have developed a truncated version of RAP d3 in which these scaffolding regions are excised and replaced with a single, intramolecular disulfide bond. This substitution allows for deletion of as much as a third of the RAP d3 sequence with substantial retention of receptor-binding ability....
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PMID: 17678622
PDF is available here.
Abstract
Proteins of the low-density lipoprotein receptor family transport cholesterol-carrying particles into cells, clear protease-inhibitor complexes from the circulation, participate in biological signaling cascades, and even serve as viral receptors. These receptors utilize clusters of cysteine-rich LDL...
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PMID: 17870468
PDF is available here.
Abstract
We have adopted a divide-and-conquer strategy to solve the structures of the individual domains of RAP using NMR spectroscopy. We present here the newly determined structure of domain 2. Based on this structure and the structures of domains 1 and 3, which were solved previously, we utilized experime...
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PMID: 17656581
PDF is available here.
Abstract
We now evaluated the binding to RAP, alpha2M*, FIXa and FVIII light chain of triplicate repeat-fragments of not only clusters II but also of cluster IV. Employing surface plasmon resonance analysis, we found that most efficient ligand-binding was displayed by the repeats within region CR4-8 of clust...
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PMID: 17512806
PDF is available here.
Abstract
We investigated whether the interaction between tPA and LRP plays a role in the regulation of the permeability of the NVU during cerebral ischemia. We found that the ischemic insult induces shedding of LRP's ectodomain from perivascular astrocytes into the basement membrane. This event associates wi...
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PMID: 17170123
PDF is available here.
Abstract
We examined the disposition profile of lanoteplase in vivo and the kinetics of receptor-mediated endocytosis (RME) of this recombinant t-PA in vitro to kinetically characterize the mechanism(s) underlying its tissue distribution and elimination. Integration plot analysis of the initial-phase tissue...
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PMID: 17178768
PDF is available here.
Abstract
We tested the hypothesis that loss of Reelin in the epileptic dentate gyrus leads to aberrant chain migration of DGC precursors. We found that interneuron subsets typically lost in human and experimental mTLE express Reelin, and DGC progenitors express the downstream Reelin signaling molecule Disabl...
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PMID: 17314278
PDF is available here.
Abstract
High levels of triglyceride-rich lipoproteins (TGRLs) in blood are linked to development of atherosclerosis, yet the mechanisms by which these particles initiate inflammation of endothelium are unknown. TGRL isolated from human plasma during the postprandial state was examined for its capacity to bi...
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PMID: 17234968
PDF is available here.
Abstract
We show that the transmembrane LRP1 (LDL receptor-related protein 1) is required for the Cu(2+)-mediated endocytosis of PrP(C) in neuronal cells. We show also that another LRP1 ligand that can cause neurodegenerative disease, the Alzheimer's amyloid precursor protein, does not modulate the endocytos...
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PMID: 17155929
PDF is available here.
Abstract
The present work attempts to determine the distribution of ACE and LRPAP1 genotypes and allele frequencies in a sample of the population of north-western Italy and to examine the age-related association of these polymorphisms. ACE D allele frequency found in this work further confirms data obtained...
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PMID: 17536759
PDF is available here.
Roberta R Botta,
Simonetta S Lisi,
Aldo A Pinchera,
Cristina C Segnani,
Luisella L Cianferotti,
Maria Antonietta MA Altea,
Francesca F Menconi,
Letizia L Mattii,
Giovanni Umberto GU Corsini,
Claudio C Marcocci,
Amelio A Dolfi,
Nunzia N Bernardini and
Michele M Marinò
Abstract
We investigated whether its expression in thyrocytes is regulated by thyroid-stimulating hormone (TSH), a feature common to all proteins involved in thyroid hormone secretion. We found by immunofluorescence that in FRTL-5 cells cultured in the presence of TSH, RAP is expressed intracellularly. The l...
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PMID: 17123336
PDF is available here.
Abstract
The biosynthesis and export of LDL receptor-related proteins rely on specialized chaperones in the endoplasmic reticulum. Two recent papers in Molecular Cell by Fisher et al. (2006) and Lee et al. (2006) reveal a novel mechanism by which one of these chaperones, the receptor-associated protein RAP,...
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PMID: 16916634
PDF is available here.
Abstract
LRP-1 is the major receptor responsible for the saturable uptake of plasma free Abeta(1-40) by the liver. Reduction of LRP-1 expression will play a role in the age-related reduction in hepatic Abeta(1-40) clearance....
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PMID: 16779710
PDF is available here.
Abstract
We show that RAP binds to lipoprotein lipase (LPL) and may play a role in the maturation of LPL. Binding of highly purified RAP to LPL was demonstrated in vitro by solid phase assays, surface plasmon resonance, and rate zonal centrifugation. The dissociation constant for this interaction measured by...
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PMID: 16517593
PDF is available here.
Abstract
The results showed that frequencies of D and I allele were 65.77% and 34.23% in patients, 76.24% and 23.76% in controls, respectively. Frequency of I allele was significantly higher in the patient group than in the control group (P = 0.003). CONCLUSION: In the present study I (insertion) allele was...
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PMID: 16704534
PDF is available here.
Abstract
We report the 1.26 A X-ray structure of a complex between a two-module region of the ligand binding domain of the LDLR and the third domain of RAP, an escort protein for LDLR family members. The RAP domain forms a three-helix bundle with two docking sites, one for each LDLR module. The mode of recog...
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PMID: 16630895
PDF is available here.
Simonetta Lisi,
Roberta Botta,
Aldo Pinchera,
A Bernard Collins,
Samuel Refetoff,
Peter Arvan,
Guojun Bu,
Lucia Grasso,
Vladimir Marshansky,
Shaliha Bechoua,
Andres Hurtado-Lorenzo,
Claudio Marcocci,
Dennis Brown,
Robert T McCluskey and
Michele Marinò
Abstract
We have studied the thyroid phenotype in RAP-knockout (RAP-KO) mice and found a reduction of Tg aggregates into thyroid follicles. Serum Tg levels were significantly increased compared with those of wild-type (WT) mice, suggesting a directional alteration of Tg secretion. In spite of these abnormali...
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PMID: 16306127
PDF is available here.
Abstract
The APOE gene (apolipoprotein E) is a major risk factor for Alzheimer's Disease (AD) but has been inconsistently associated with memory in nondemented adults. Two other genes with mixed support as genetic risk factors for AD, A2M (alpha-2-macroglobulin) and LRP (low-density lipoprotein receptor-rela...
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PMID: 16402284
PDF is available here.
Abstract
We conclude that the residues mentioned above play a key role in formation of the A2 binding epitope for LRP. Experiments in mice revealed an approximately 4.5 times shorter half-life for A2 in the circulation in comparison with that of fVIII. The half-lives of A2 mutant R471A/R484A or A2 co-injecte...
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PMID: 16460029
PDF is available here.
Abstract
Three brand new mutations, not reported so far, have been detected--Pro2712Leu and Ile3532 in the apoB100 gene, and Cys347Ser in the LDLR gene--and numerous changes in the nucleotide sequence of the LDL receptor gene have been confirmed. The observations of functionality of the mutated receptor gene...
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PMID: 16502360
PDF is available here.
Abstract
We aimed to examine the role of LRPAP1 polymorphism in susceptibility to GBC.
Present case control study included 129 proven GBC patients, 183 gallstone patients, and 208 healthy controls. Genotyping was done by polymerase chain reaction-restriction fragment length polymorphism metho...
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PMID: 17987404
PDF is available here.
Abstract
We test whether Mesd, a newly identified chaperone for members of the low-density lipoprotein receptor family, also binds to mature receptors at the cell surface and antagonizes ligand binding. We found that Mesd binds to cell surface LRP5 and LRP6, but not to other members of the low-density lipopr...
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PMID: 16263759
PDF is available here.
Abstract
Megalin is a multifunctional endocytic receptor that is expressed in renal proximal tubules and plays critical roles in the renal uptake of various proteins. It was hypothesized that megalin-dependent endocytosis might play a role in renal phosphate reabsorption. For addressing the short-term effect...
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PMID: 15976002
PDF is available here.
Abstract
We have previously reported that, apart from LRP, other RAP-sensitive mechanisms contribute to the regulation of FVIII in vivo. In the present study, we showed that the extracellular ligand-binding domain of LDLR interacts with FVIII in vitro and that binding was inhibited by RAP. The physiologic re...
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PMID: 15840700
PDF is available here.
Abstract
We analyzed how N-linked glycosylation and molecular chaperones function during LRP folding. Treatment of cells with a glycosylation inhibitor tunicamycin significantly impaired LRP folding, although binding to receptor-associated protein (RAP), a specialized chaperone for LRP, was not affected. The...
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PMID: 15823038
PDF is available here.
Abstract
The molecular mechanism of the Chinese traditional medicine 'Bushen Yinao Pian' (a complex prescription used for clinical anti-ageing in China for over 20 years) is elusive. In this study, the cDNA of low-density lipoprotein related-receptor associated protein-1 (LRPAP-1), an ageing-related gene, wh...
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PMID: 15763364
PDF is available here.
Abstract
Nephrotic syndrome (N-S) is associated with elevated plasma concentration and impaired clearance of VLDL, chylomicrons (CM), and their atherogenic remnants. These abnormalities are largely due to lipoprotein lipase, hepatic triglyceride lipase, and VLDL receptor deficiencies and impaired HDL-mediate...
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PMID: 15585592
PDF is available here.
Abstract
We have investigated expression of two of these receptors in MS lesions, annexin II tetramer (AIIt) and low-density lipoprotein receptor-related protein (LRP). In acute MS lesions both AIIt and LRP were immunolocalized on macrophages and astrocytes while LRP was additionally found on neuronal cells...
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PMID: 15793294
PDF is available here.
Abstract
We have studied binding/internalization of human low density lipoprotein (LDL), mediated by bovine LPL, using THP-1 monocytes and macrophages. Uptake of (125)I-LDL was similar in monocytes and macrophages and was not affected by the LDL-receptor family antagonist receptor-associated protein (RAP) or...
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PMID: 15522821
PDF is available here.
Abstract
We summarize recent evidence why the receptor for advanced glycation end products and low-density lipoprotein receptor related protein 1 in the vascular CNS barriers are critical for regulation of Abeta homeostasis in the CNS and how altered activities in these 2 receptors at the blood-brain barrier...
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PMID: 15459432
PDF is available here.
Abstract
We have sought to identify a high-capacity transport system that mediates transcytosis of proteins from the blood to the brain. The 39 kDa receptor-associated protein (RAP) functions as a specialized endoplasmic reticulum chaperone assisting in the folding and trafficking of members of the low-densi...
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PMID: 15383619
PDF is available here.
Abstract
We treated multiple neural and non-neural cell lines for 24 h with apoE at concentrations similar to those found in the cerebrospinal fluid (1-5 microg/mL). The apoE treatment reduced Abeta40 by 60-80% and Abeta42 to a lesser extent (20-30%) in the conditioned media. Surprisingly, apoE treatment res...
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PMID: 15312168
PDF is available here.
Abstract
We examine a specific mechanism for TGFbeta2-mediated targeting of Abeta to neurons. The receptor-associated protein (RAP), a low-density lipoprotein receptor-related protein (LRP) antagonist, can attenuate the cellular targeting of Abeta both in vitro and in vivo and prevent Abeta/TGFbeta2-induced...
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PMID: 15211588
PDF is available here.
Abstract
We show that sorLA interacts with both components of the plasminogen activating system and PDGF-BB similarly to LRP1 (LDL receptor-related protein/alpha2-macroglobulin receptor), which is an important clearance receptor with established functions in controlling uPAR expression as well as PDGF-BB sig...
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PMID: 15053742
PDF is available here.
Abstract
We analyzed changes in the pattern of gene expression in human THP-1 macrophages treated with atorvastatin and oxidized-LDL (oxLDL). To this end, we used a human cDNA array containing 588 cardiovascular-related cDNAs. Exposure to oxLDL resulted in differential expression of 26 genes, while coincubat...
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PMID: 15110783
PDF is available here.
Abstract
We first established compartmented cultures of CNS neurons (retinal ganglion cells). Addition of glial cell-conditioned medium (GCM) to distal axons increased the rate of axon extension by approximately 50%. Inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase in glial cells diminished the secreti...
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PMID: 14709547
PDF is available here.
Abstract
The low-density lipoprotein receptor-related protein (LRP) is a large (>600 kDa) multi-ligand-binding cell surface receptor that is now known to participate in a diverse range of cellular events. To accomplish this diverse role, LRP is composed of repetitive amino acid motifs consisting of complemen...
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PMID: 14980518
PDF is available here.
Abstract
We find that M protein, released from the streptococcal surface, forms complexes with fibrinogen, which by binding to beta2 integrins of neutrophils, activate these cells. As a result, neutrophils release heparin binding protein, an inflammatory mediator inducing vascular leakage. In mice, injection...
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PMID: 15016372
PDF is available here.
Abstract
We have developed a gene delivery system using RAP as a targeting ligand. A RAP cDNA lacking a C-terminal heparin-binding domain was amplified by polymerase chain reaction (PCR) from a human liver cDNA library and was reamplified by using a primer containing a cysteine codon at its carboxyl end to f...
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PMID: 15025528
PDF is available here.
Abstract
We show that a subset of CD11c(+) lineage-negative (lin(-)) DC expresses the scavenger receptor CD91/LRP and that these rare APC are primarily responsible for the T cell activation that occurs following CD91/LRP-mediated Ag uptake in whole blood. The targeting of Ags to CD91/LRP results in enhanced...
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PMID: 14688311
PDF is available here.
Abstract
We have expressed RAP subfragments and examined them by two-dimensional HSQC NMR and fluorescence spectroscopies, by differential scanning calorimetry, and by both equilibrium and velocity sedimentation measurements. We found that the protein is organized into three domains located in the first thir...
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PMID: 14674767
PDF is available here.
Abstract
We used the short interfering RNA (siRNA) technique to explore the role of LRP in smooth muscle cell migration. We identified an LRP-specific siRNA that selective silences LRP expression in human aortic smooth muscle cells. As a consequence, LRP-mediated ligand degradation was significantly reduced....
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PMID: 14644440
PDF is available here.
Abstract
We investigated whether RAP is involved in Tg secretion by FRTL-5 cells. For this purpose, we studied Tg secretion by FRTL-5 cells transfected with a soluble RAP chimera, as a mean for interfering with endogenous RAP. We used a RAP-human IgG Fc (RAP-Ig) chimeric cDNA, which was designed in order to...
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PMID: 15008249
PDF is available here.
Abstract
Ever more unexpected roles for the LDL receptor gene family in a variety of cellular signaling pathways continue to emerge. Three recent studies now add another function to this collection. By interacting with active tissue-type plasminogen activator, LDL receptor-related protein appears to control...
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PMID: 14617749
PDF is available here.