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Transfer Protein (transfer + protein)
Kinds of Transfer Protein Terms modified by Transfer Protein Selected AbstractsCholesteryl Ester Transfer Protein (CETP) Genetic Variation and Early Onset of Non-Fatal Myocardial InfarctionANNALS OF HUMAN GENETICS, Issue 6 2008V. Meiner Summary Although Cholesteryl Ester Transfer Protein (CETP) mediates the transfer of cholesteryl esters and triglycerides between lipoprotein particles and thus plays a crucial role in reverse cholesterol transport, the association of variations in the CETP gene with acute myocardial infarction (MI) remains unclear. In this study we examined whether common genetic variation in the CETP gene is related to early-onset non-fatal MI risk in a population-based case-control study from western Washington State. Genotyping for the CETP ,2708 G/A, ,971 A/G, ,629 A/C, Intron-I TaqI G/A and exon-14 A/G (I405V) SNPs was performed in 578 cases with first acute non-fatal MI and in 666 demographically similar controls, free of clinical cardiovascular disease, identified randomly from the community. In-person interviews and non-fasting blood specimens provided data on coronary heart disease risk factors. In men, there was little evidence for an association between single SNPs and MI risk, but in women the age- and race-adjusted OR was found to be significant in 4 out of the 5 CETP single variants. Haplotype analysis revealed two haplotypes associated with MI risk among men. As compared to men homozygous for the most common haplotype D (,2708 G, ,971 G, ,629 C, TaqI G and exon-14 A), the fully-adjusted multiplicative model identified haplotype G (,2708 G, ,971 A, ,629 A, TaqI G and exon-14 G) was associated with a 4.0-6.0-fold increased risk of MI for each additional copy; [95%CI 2.4,14.8] and haplotype B (,2708 G, ,971 G, ,629 A, TaqI A and exon-14 A) showed a significant decreased risk for early onset MI [OR = 0.18; 95%CI 0.04 , 0.75]. An evolutionary-based haplotype analysis indicated that the two haplotypes associated with the MI risk are most evolutionarily divergent from the other haplotypes. Variation at the CETP gene locus is associated with the risk of early-onset non-fatal MI. This association was found to be independent of HDL-C levels. These data and the sex-specific findings require confirmation in other populations. [source] CETP inhibition in cardiovascular risk management: a critical appraisalEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 2 2007R. P. F. Dullaart Abstract In view of the cardioprotective effect of high-density lipoproteins (HDL) and the limited effects of statin and fibrate therapy on HDL cholesterol, it is clinically relevant to test whether pharmacological treatment aimed at raising HDL lowers cardiovascular risk. Cholesteryl ester transfer protein (CETP) is a new therapeutic target, because the cholesteryl ester transfer process lowers HDL cholesterol and contributes to an atherogenic lipoprotein profile, particularly when plasma triglycerides are high. Clinical evidence suggests that coronary artery calcification as well as intima media thickness is positively related to plasma cholesteryl ester transfer, and that high plasma CETP concentration is associated with increased cardiovascular risk in hypertriglyceridaemia. However, CETP could also have anti-atherogenic potential, since it provides a potentially beneficial route for delivery of HDL-derived cholesteryl esters to the liver. In addition, CETP could also favourably stimulate peripheral cell cholesterol removal and enhance hepatic cholesterol uptake. Recent evidence suggests that a high CETP level may confer lower cardiovascular risk in the context of low triglycerides. At maximal doses, the CETP inhibitors JTT-705 and torcetrapib elicit a marked rise in HDL cholesterol of up to 34% and 91,106%, respectively. The effectiveness of these drugs on (intermediate) clinical outcome measures is currently being tested in large-scale phase III clinical trials, with torcetrapib being only evaluated in combination therapy with atorvastatin. When and how to use CETP inhibitors, e.g. in combination with a statin or a fibrate, is a major challenge. We propose that low HDL cholesterol in the context of high triglycerides, such as found in type 2 diabetes mellitus, could become an important indication area for this new class of drugs. [source] Metabolism of cholesterol ester of apolipoprotein B100-containing lipoproteins in dogs: evidence for disregarding cholesterol ester transferEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 8 2004E. Bailhache Abstract Background, It has been shown that dogs exhibit no cholesterol ester transfer protein (CETP) activity in vitro, in contrast to humans. The aim of our study was to determine modalities of in vivo plasma cholesterol ester turnover in this species, using a kinetic approach with stable isotopes. Materials and methods, Kinetics of very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) were studied in seven adult male Beagle dogs using a dual isotope approach through endogenous labelling of both their cholesterol moiety and their protein moiety. A primed constant infusion of both [1,213C]acetate and [5,5,5- 2H3]leucine enabled us to obtain measurable deuterium enrichments by gas chromatography-mass spectrometry for plasma leucine and apoB100, as well as measurable 13C enrichment by gas chromatography-combustion-isotopic ratio mass spectrometry for unesterified cholesterol and cholesterol ester in the VLDL and LDL. Two identical multicompartmental models (SAAM II) were used together for the analysis of tracer kinetics' data of proteins and cholesterol. Results, Characterization of the apoB100-containing lipoprotein cholesterol ester model allowed determination of kinetic parameters of VLDL and LDL cholesterol ester metabolism. We succeeded in modelling VLDL and LDL cholesterol ester metabolism and apoB100 metabolism simultaneously. Fractional catabolic rate (FCR) of apoB100 and CE had the same values. Introducing cholesterol ester transfer between lipoproteins in the model did not significantly improve the fit. Total VLDL FCR was 2·97 ± 01·47 h,1. Approximately one-quarter corresponded to the direct removal of VLDL (0·81 ± 00·34 h,1) and the remaining three-quarters corresponded to the fraction of VLDL converted to LDL, which represented a conversion of VLDL into LDL of 2·16 ± 01·16 h,1. Low-density lipoproteins were produced exclusively from VLDL conversion and were then removed (0·031 ± 0·004 h,1) from plasma. Conclusion, These kinetic data showed that VLDL cholesterol ester and LDL cholesterol ester metabolism followed VLDL and LDL apoB100 metabolism, and that consequently there is no in vivo transfer of cholesterol ester in dogs. [source] Microsomal triglyceride transfer protein regulates endogenous and exogenous antigen presentation by group,1 CD1 moleculesEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2008Arthur Kaser Abstract Lipid antigens are presented to T cells by the non-polymorphic MHC class,I-related CD1 molecules. Microsomal triglyceride transfer protein (MTP) is an endoplasmic reticulum (ER)-resident chaperone that has been shown to lipidate the group,2 CD1 molecule CD1d and thus to regulate its function. We now report that MTP also regulates the function of group,1 CD1 molecules CD1a, CD1b, and CD1c. Pharmacological inhibition of MTP in monocyte-derived dendritic cells and lymphoblastoid B cell lines transfected with group,1 CD1 resulted in a substantial decrease in endogenous self lipid antigen presentation to several CD1-restricted T cell lines. Silencing MTP expression in CD1c-transfected HeLa cells similarly resulted in decreased self reactivity. Unexpectedly, inhibition of ER-resident MTP, which was confirmed by confocal microscopy, also markedly decreased presentation of exogenous, endosomally loaded, mycobacterial lipid antigens by CD1a and CD1c to T cells. Thus, these studies indicate that MTP, despite its ER localization, regulates endogenous as well as exogenous lipid antigen presentation, and suggest a broad role for MTP in the regulation of CD1 antigen presentation. [source] pH-dependent translocation of ,-tocopherol transfer protein (,-TTP) between hepatic cytosol and late endosomesGENES TO CELLS, Issue 10 2003Masakuni Horiguchi Background:, ,-Tocopherol transfer protein (,-TTP), a member of the Sec14 protein family, plays an important role in transporting ,-tocopherol, a major lipid-soluble anti-oxidant, in the cytosolic compartment of hepatocytes and is known as a product of the causative gene for familial isolated vitamin E deficiency. It has been shown that the secretion of hepatocyte ,-tocopherol taken up with plasma lipoproteins is facilitated by ,-TTP. To explore the mechanism of ,-TTP mediated ,-tocopherol secretion, we investigated drugs which may affect this secretion. Results:, We found that, in a hepatocyte cell culture system, intracellular ,-tocopherol transport is impaired by chloroquine, an agent known for its function of elevating the pH in acidic compartments. Under chloroquine treatment, the diffuse cytosolic distribution of ,-TTP changes to a punctate pattern. Double-staining experiments with endocytosis markers revealed that ,-TTP accumulates transiently on the cytoplasmic surface of late endosomal membranes. This phenomenon is specific for hepatoma cell lines or primarily cultured hepatocytes. Other members of the Sec14 family, such as cellular retinaldehyde-binding protein (CRALBP) and supernatant protein factor (SPF), do not show this accumulation. Furthermore, we elucidate that the obligatory amino acid sequence for this function is located between amino acids 21 and 50, upstream of the N-terminal end of the lipid-binding domain. Conclusion:, We hypothesize that a liver-specific target molecule for ,-TTP exists on the late endosomal membrane surface. This transient binding may explain the mechanism of how ,-tocopherol is transferred from late endosomes to cytosolic ,-TTP. [source] Molecular characterization of the role of orphan receptor small heterodimer partner in development of fatty liver,HEPATOLOGY, Issue 1 2007Jiansheng Huang The orphan receptor Small Heterodimer Partner (SHP, NROB2) regulates metabolic pathways, including hepatic bile acid, lipid, and glucose homeostasis. We reported that SHP- deletion in leptin-deficient OB,/, mice increases insulin sensitivity, and prevents the development of fatty liver. The prevention of steatosis in OB,/,/SHP,/, double mutants is not due to decreased body weight but is associated with increased hepatic very-low-density lipoprotein (VLDL) secretion and elevated microsomal triglyceride transfer protein (MTP) mRNA and protein levels. SHP represses the transactivation of the MTP promoter and the induction of MTP mRNA by LRH-1 in hepatocytes. Adenoviral overexpression of SHP inhibits MTP activity as well as VLDL-apoB protein secretion, and RNAi knockdown of SHP exhibits opposite effects. The expression of SHP in induced in fatty livers of OB,/, mice and other genetic or dietary models of steatosis, and acute overexpression of SHP by adenovirus, result in rapid accumulation of neutral lipids in hepatocytes. In addition, the pathways for hepatic lipid uptake and lipogenic program are also downregulated in OB,/,/SHP,/, mice, which may contribute to the decreased hepatic lipid content. Conclusion: These studies demonstrate that SHP regulates the development of fatty liver by modulating hepatic lipid export, uptake, and synthesis, and that the improved peripheral insulin sensitivity in OB,/,/SHP,/, mice is associated with decreased hepatic steatosis. (HEPATOLOGY 2007.) [source] Inhibition of microsomal triglyceride transfer protein: Another mechanism for drug-induced steatosis in miceHEPATOLOGY, Issue 1 2003Philippe Lettéron Although many steatogenic drugs inhibit mitochondrial fatty acid ,-oxidation, limited information is available on possible effects on hepatic lipoprotein secretion. In the endoplasmic reticulum (ER) lumen, microsomal triglyceride transfer protein (MTP) lipidates apolipoprotein B (Apo B), to form triglyceride (TG)-rich very low density lipoprotein (VLDL) particles, which follow vesicular flow to the plasma membrane to be secreted, whereas incompletely lipidated Apo B particles are partly degraded. We studied hepatic MTP activity, the lipoproteins present in the ER lumen, and hepatic lipoprotein secretion 4 hours after administration of a single dose of amineptine (1 mmol/kg), amiodarone (1 mmol/kg), doxycycline (0.25 mmol/kg), tetracycline (0.25 mmol/kg), tianeptine (0.5 mmol/kg), or pirprofen (2 mmol/kg) in mice. These various doses have been shown previously to markedly inhibit fatty acid oxidation after a single dose, and to trigger steatosis either after repeated doses (doxycycline) or a single dose (other compounds) in mice. In the present study, amineptine, amiodarone, pirprofen, tetracycline, and tianeptine, but not doxycycline, inhibited MTP activity in vitro, decreased ex vivo MTP activity in the hepatic homogenate of treated mice, decreased TG in the luminal VLDL fraction of hepatic microsomes of treated mice, and decreased in vivo hepatic lipoprotein secretion (TG and Apo B). In conclusion, several steatogenic drugs inhibit not only mitochondrial ,-oxidation, as previously shown, but also MTP activity, Apo B lipidation into TG-rich VLDL particles, and hepatic lipoprotein secretion. Drugs with these dual effects may be more steatogenic than drugs acting only on ,-oxidation or only MTP. [source] Functional analysis of promoter variants in the microsomal triglyceride transfer protein (MTTP) gene,HUMAN MUTATION, Issue 1 2008Diana Rubin Abstract The microsomal triglyceride transfer protein (MTTP) is required for the assembly and secretion of apolipoprotein B (apoB)-containing lipoproteins from the intestine and liver. According to this function, polymorphic sites in the MTTP gene showed associations to low-density lipoprotein (LDL) cholesterol and related traits of the metabolic syndrome. Here we studied the functional impact of common MTTP promoter polymorphisms rs1800804:T>C (,164T>C), rs1800803:A>T (,400A>T), and rs1800591:G>T (,493G>T) using gene-reporter assays in intestinal Caco-2 and liver Huh-7 cells. Significant results were obtained in Huh-7 cells. The common MTTP promoter haplotype ,164T/,400A/,493G showed about two-fold lower activity than the rare haplotype ,164C/,400T/,493T. MTTP promoter mutant constructs ,164T/,400A/,493T and ,164T/,400T/,493T exhibited similar activity than the common haplotype. Activities of mutants ,164C/,400A/,493G and ,164C/,400A/,493T resembled the rare MTTP promoter haplotype. Electrophoretic mobility shift assays (EMSAs) revealed higher binding capacity of the transcriptional factor Sterol regulatory element binding protein1a (SREBP1a) to the ,164T probe in comparison to the ,164C probe. In conclusion, our study indicates that the polymorphism ,164T>C mediates different activities of common MTTP promoter haplotypes via SREBP1a. This suggested that the already described SREBP-dependent modulation of MTTP expression by diet is more effective in ,164T than in ,164C carriers. Hum Mutat 29(1), 123,129, 2008. © 2007 Wiley-Liss, Inc. [source] A phosphatidylinositol transfer protein ,-dependent survival factor protects cultured primary neurons against serum deprivation-induced cell deathJOURNAL OF NEUROCHEMISTRY, Issue 3 2006Hanneke Bunte Abstract Selective neuronal loss is a prominent feature in both acute and chronic neurological disorders. Recently, a link between neurodegeneration and a deficiency in the lipid transport protein phosphatidylinositol transfer protein , (PI-TP,) has been demonstrated. In this context it may be of importance that fibroblasts overexpressing PI-TP, are known to produce and secrete bioactive survival factors that protect fibroblasts against UV-induced apoptosis. In the present study it was investigated whether the conditioned medium of cells overexpressing PI-TP, (CM,) has neuroprotective effects on primary neurons in culture. We show that CM, is capable of protecting primary, spinal cord-derived motor neurons from serum deprivation-induced cell death. Since the conditioned medium of wild-type cells was much less effective, we infer that the neuroprotective effect of CM, is linked (in part) to the PI-TP,-dependent production of arachidonic acid metabolites. The neuroprotective activity of CM, is partly inhibited by suramin, a broad-spectrum antagonist of G-protein coupled receptors. Western blot analysis shows that brain cortex and spinal cord express relatively high levels of PI-TP,, suggesting that the survival factor may be produced in neuronal tissue. We propose that the bioactive survival factor is implicated in neuronal survival. If so, PI-TP, could be a promising target to be evaluated in studies on the prevention and treatment of neurological disorders. [source] Phospholipid transfer protein reduces phosphorylation of tau in human neuronal cellsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 14 2009Weijiang Dong Abstract Tau function is regulated by phosphorylation, and abnormal tau phosphorylation in neurons is one of the key processes associated with development of Alzheimer's disease and other tauopathies. In this study we provide evidence that phospholipid transfer protein (PLTP), one of the main lipid transfer proteins in the brain, significantly reduces levels of phosphorylated tau and increases levels of the inactive form of glycogen synthase kinase-3, (GSK3,) in HCN2 cells. Furthermore, inhibition of phosphatidylinositol-3 kinase (PI3K) reversed the PLTP-induced increase in levels of GSK3, phosphorylated at serine 9 (pGSK3,Ser9) and partially reversed the PLTP-induced reduction in tau phosphorylation. We provide evidence that the PLTP-induced changes are not due to activation of Disabled-1 (Dab1), insofar as PLTP reduced levels of total and phosphorylated Dab1 in HCN2 cells. We have also shown that inhibition of tyrosine kinase activity of insulin receptor (IR) and/or insulin-like growth factor 1 (IGF1) receptor (IGFR) reverses the PLTP-induced increase in levels of phosphorylated Akt (pAktThr308 and pAktSer473), suggesting that PLTP-mediated activation of the PI3K/Akt pathway is dependent on IR/IGFR receptor tyrosine kinase activity. Our study suggests that PLTP may be an important modulator of signal transduction pathways in human neurons. © 2009 Wiley-Liss, Inc. [source] HDL2 of Heavy Alcohol Drinkers Enhances Cholesterol Efflux From Raw Macrophages via Phospholipid-Rich HDL2b ParticlesALCOHOLISM, Issue 6 2008Sanna M. Mäkelä Background:, Alcohol consumption is associated with increased serum high density lipoprotein (HDL) cholesterol levels and a decreased risk for the development of atherosclerosis. However, the effects of heavy alcohol intake on reverse cholesterol transport, one of the key anti-atherogenic processes related to HDL, are poorly known. Methods:, The ability of total HDL as well as HDL2 and HDL3 subclasses to promote cholesterol efflux from 3H-cholesterol-labeled RAW 264.7 macrophages was studied among 6 heavy alcohol drinkers and 6 controls. Distribution of HDL subclasses was analyzed by 4 to 30% native gradient gels. Serum phospholipid transfer protein (PLTP) and cholesteryl ester transfer protein (CETP) activities were analyzed among several other biochemical measures. Results:, Cholesterol efflux to HDL2 of heavy drinkers was 22% (p = 0.025) higher relative to controls. The increase in HDL2 phospholipids, with a concomitant 2-fold (p = 0.055) increase in large HDL2b particles, was associated with enhanced cholesterol efflux to HDL2. Interestingly, the cholesterol efflux to HDL3 did not differ between the 2 study groups. These findings may be partially explained by a decreased CETP activity (,26%, p = 0.037) and an increased PLTP activity (39%, p = 0.045) in heavy drinkers. Conclusions:, The increased cholesterol efflux potential of HDL2 is most likely an anti-atherogenic feature linked to heavy alcohol consumption. The cholesterol efflux and HDL phospholipids also associated strongly within the whole study group (rs = 0.910, p , 0.01) suggesting a common pathway of enhanced cholesterol efflux via enlarged phospholipid-rich HDL particles. [source] Lipid metabolism and occurrence of post-percutaneous transluminal coronary angioplasty restenosis: role of cholesteryl ester transfer protein and paraoxonase/arylesteraseJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 6 2003R. Y. L. Zee Summary., Plasma lipid metabolic and transfer processes have recently been suggested to play an important role in the development of early restenosis, a major complication of percutaneous transluminal coronary angioplasty (PTCA); in particular, the common variants of genes for cholesteryl ester transfer protein (CETP) and paraoxonase (PONA) have been implicated. We had the opportunity to investigate this question in a large, prospective cohort characterized by quantitative coronary angiography in all subjects. The CETP-TaqIB (intron 1), CETP-MspI (intron 8), and PONA-AlwI (exon 2) polymorphisms were characterized in a cohort of 779 patients of whom 342 (,cases') had developed restenosis (as defined by >,50% loss of lumen compared with immediate postprocedure results) at repeat angiography at 6 months post PTCA. Selected frequencies for CETP B1 and B2 alleles (absence/presence of TaqIB site) were 0.65 and 0.35 (cases) and 0.65 and 0.35 (controls), respectively; frequencies for CETP M1 and M2 alleles (absence/presence of MspI site) were 0.20 and 0.80 (cases), 0.21 and 0.79 (controls), respectively; frequencies for PONA A and B alleles (absence/presence of AlwI site) were 0.73 and 0.27 (cases), 0.72 and 0.28 (controls), respectively. All observed genotype frequencies were in Hardy,Weinberg equilibrium. There was no evidence for gene,gene interaction, or an association between genotype and restenosis or degree of lumen loss (adjusted for covariates). Our data, collected in the largest study of its kind so far, indicate that the common variants for CETP and PONA are not associated with incidence of restenosis after PTCA, and are therefore not useful markers for risk assessment. [source] Genes or environment to determine alcoholic liver disease and non-alcoholic fatty liver diseaseLIVER INTERNATIONAL, Issue 9 2006C. P. Day Abstract: While the vast majority of heavy drinkers and individuals with obesity, insulin resistance, and the metabolic syndrome will have steatosis, only a minority will ever develop steatohepatitis, fibrosis, and cirrhosis. Genetic and environmental risk factors for advanced alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) seem likely to include factors that influence the severity of steatosis and oxidative stress, the cytokine milieu, the magnitude of the immune response, and/or the severity of fibrosis. For ALD, the dose and pattern of alcohol intake, along with obesity are the most important environmental factors determining disease risk. For NAFLD, dietary saturated fat and antioxidant intake and small bowel bacterial overgrowth may play a role. Family studies and interethnic variations in susceptibility suggest that genetic factors are important in determining disease risk. For ALD, functional polymorphisms in the alcohol dehydrogenases and aldehyde dehydrogenase alcohol metabolising genes play a role in determining susceptibility in Oriental populations. No genetic associations with advanced NAFLD have been replicated in large studies. Preliminary data suggest that polymorphisms in the genes encoding microsomal triglyceride transfer protein, superoxide dismutase 2, the CD14 endotoxin receptor, TNF-,, transforming growth factor-,, and angiotensinogen may be associated with steatohepatitis and/or fibrosis. [source] Recurrent familial hypobetalipoproteinemia,induced nonalcoholic fatty liver disease after living donor liver transplantationLIVER TRANSPLANTATION, Issue 7 2009Noboru Harada Familial hypobetalipoproteinemia (FHBL) is one of the causes of nonalcoholic steatohepatitis (NASH) and a codominant disorder. Patients heterozygous for FHBL may be asymptomatic, although they demonstrate low plasma levels of low-density lipoprotein (LDL) cholesterol and apolipoprotein B. Here we report a nonobese 54-year-old man with decompensated liver cirrhosis who underwent living donor liver transplantation with his son as the donor. Low albuminemia and refractory ascites persisted after transplantation. A biopsy specimen obtained 11 months after liver transplantation revealed severe steatosis and fibrosis, and recurrent NASH was diagnosed on the basis of pathological findings. Both the patient's and donor's laboratory tests demonstrated low LDL cholesterol and apolipoprotein levels. Because mutations in messenger RNAs of microsomal triglyceride transfer protein and apolipoprotein B genes were excluded neither in the recipient nor in the donor, both were clinically diagnosed as being heterozygous for FHBL. We successfully treated the recipient with heterozygous FHBL,induced recurrent NASH after liver transplantation using our diet and exercise programs. Liver Transpl 15:806,809, 2009. © 2009 AASLD. [source] Anaphylaxis to lipid transfer protein from sunflower seedsALLERGY, Issue 10 2010A. Yagami No abstract is available for this article. [source] Biochemical, immunological and clinical characterization of a cross-reactive nonspecific lipid transfer protein 1 from mulberryALLERGY, Issue 5 2010M. A. Ciardiello To cite this article: Ciardiello MA, Palazzo P, Bernardi ML, Carratore V, Giangrieco I, Longo V, Melis M, Tamburrini M, Zennaro D, Mari A, Colombo P. Biochemical, immunological and clinical characterization of a cross-reactive nonspecific lipid transfer protein 1 from mulberry. Allergy 2010; 65: 597,605. Abstract Background:, Mulberry (Morus spp.) is a genus comprising several species of deciduous trees whose fruits are commonly eaten in southern Europe. Subjects with severe systemic reaction have been described. The aim of this study was to isolate the allergens of this species. Methods:, A nonspecific lipid transfer protein 1 (ns-LTP1) was purified from black mulberry by ion exchange and reverse phase high-performance liquid chromatography, and the primary structure was elucidated by direct protein sequencing. Its allergenic activity was evaluated in vivo by skin prick test and in vitro by Western Blot, CD203c basophil activation assay and high throughput multiplex inhibition method on immunosolid-phase allergen chip (ISAC). Results:, Mulberry ns-LTP (Mor n 3) comprises 91 amino acids producing a molecular mass of 9246 Da. This protein shows high sequence identity with several allergenic ns-LTP1. Immunoblot analysis and CD203c activation assay demonstrated its allergenic activity in symptomatic subjects and in ns-LTP allergic patients who are not mulberry consumers. Immunological co-recognition was studied in vivo on a selected group of well-characterized ns-LTP allergic patients showing a high percentage of nMor n 3+ subjects (88.46%) even in patients who have never eaten mulberry before. IgE inhibition on ISAC micro-array demonstrated an almost complete cross-reactivity to nArt v 3, rCor a 8 and a very high percentage of inhibition to nPru p 3. Conclusions:, Mor n 3 is the first allergen isolated in black mulberry and immunologically characterized. It displayed allergenic activity among symptomatic and nonconsumer patients and a pattern of cross-reactivity to other plant-derived LTPs. [source] 10 kDa lipid transfer protein: the main allergenic structure in a German patient with anaphylaxis to blueberryALLERGY, Issue 3 2009C. Gebhardt No abstract is available for this article. [source] Screening the allergenic repertoires of wheat and maize with sera from double-blind, placebo-controlled food challenge positive patientsALLERGY, Issue 1 2006M. Weichel Background:, Food allergy to wheat and maize is an increasing factor of deterioration of life quality, especially childhood and can, in rare cases, even induce anaphylaxis. Although omega-5 gliadin from wheat and maize lipid transfer protein have been characterized as major cereal allergens on the molecular level, the list of food allergens is far to be complete. Methods:, To identify the IgE-binding repertoires of wheat and maize we screened respective cDNA libraries displayed on phage surface with sera from patients with a confirmed food allergy. The study included six patients with a positive double-blind, placebo-controlled food challenge (DBPCFC) to wheat, nine patients with a positive DBPCFC to maize, and six patients with anaphylactic reactions after ingestion of wheat. Results:, The enriched sequences encoding IgE-binding proteins showed heterogeneous repertoires for both, wheat and maize. The selected wheat repertoire yielded 12, the maize repertoire 11 open reading frames. Among these we identified allergens belonging to already characterized allergens families, such as gliadin, profilin and beta-expansin. Besides, we found novel proteins with high cross-reactive potential, such as thioredoxins, as well as sequences that had so far not been related to cereal allergy at all. The IgE-binding capacity of some selected proteins was evaluated in vitro and cross-reactivity was demonstrated by competition ELISA. Conclusion:, With regard to the heterogeneity of the characterized sequences as well as to the biochemical nature of the new allergens detected we conclude that wheat and maize-related food allergy is more complex than so far anticipated. [source] PDR16 -mediated azole resistance in Candida albicansMOLECULAR MICROBIOLOGY, Issue 6 2006Saloua Saidane Summary Many Candida albicans azole-resistant (AR) clinical isolates overexpress the CDR1 and CDR2 genes encoding homologous multidrug transporters of the ATP-binding cassette family. We show here that these strains also overexpress the PDR16 gene, the orthologue of Saccharomyces cerevisiae PDR16 encoding a phosphatidylinositol transfer protein of the Sec14p family. It has been reported that S. cerevisiae pdr16, mutants are hypersusceptible to azoles, suggesting that C. albicans PDR16 may contribute to azole resistance in these isolates. To address this question, we deleted both alleles of PDR16 in an AR clinical strain overexpressing the three genes, using the mycophenolic acid resistance flipper strategy. Our results show that the homozygous pdr16,/pdr16, mutant is approximately twofold less resistant to azoles than the parental strain whereas reintroducing a copy of PDR16 in the mutant restored azole resistance, demonstrating that this gene contributes to the AR phenotype of the cells. In addition, overexpression of PDR16 in azole-susceptible (AS) C. albicans and S. cerevisiae strains increased azole resistance by about twofold, indicating that an increased dosage of Pdr16p can confer low levels of azole resistance in the absence of additional molecular alterations. Taken together, these results demonstrate that PDR16 plays a role in C. albicans azole resistance. [source] VirE2, a Type IV secretion substrate, interacts with the VirD4 transfer protein at cell poles of Agrobacterium tumefaciensMOLECULAR MICROBIOLOGY, Issue 6 2003Krishnamohan Atmakuri Summary Agrobacterium tumefaciens transfers oncogenic DNA and effector proteins to plant cells during the course of infection. Substrate translocation across the bacterial cell envelope is mediated by a type IV secretion (TFS) system composed of the VirB proteins, as well as VirD4, a member of a large family of inner membrane proteins implicated in the coupling of DNA transfer intermediates to the secretion machine. In this study, we demonstrate with novel cytological screens , a two-hybrid (C2H) assay and bimolecular fluorescence complementation (BiFC) , and by immunoprecipitation of chemically cross-linked protein complexes that the VirE2 effector protein interacts directly with the VirD4 coupling protein at cell poles of A. tumefaciens. Analyses of truncation derivatives showed that VirE2 interacts via its C terminus with VirD4, and, further, an NH2 -terminal membrane-spanning domain of VirD4 is dispensable for complex formation. VirE2 interacts with VirD4 independently of the virB -encoded transfer machine and T pilus, the putative periplasmic chaperones AcvB and VirJ, and the T-DNA transfer intermediate. Finally, VirE2 is recruited to polar-localized VirD4 as a complex with its stabilizing secretion chaperone VirE1, yet the effector,coupling protein interaction is not dependent on chaperone binding. Together, our findings establish for the first time that a protein substrate of a type IV secretion system is recruited to a member of the coupling protein superfamily. [source] Purification and structural stability of the peach allergens Pru p 1 and Pru p 3MOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue S2 2008Sonja Gaier Abstract Pru p 1 (a Bet v 1 homologue) and Pru p 3 (a nonspecific lipid transfer protein; nsLTP) are major allergenic proteins in peach fruit, but differ in their abundance and stability. Pru p 1 has low abundance and is highly labile and was purified after expression as a recombinant protein in Escherichia coli. Pru p 3 is highly abundant in peach peel and was purified by conventional methods. The identities of the proteins were confirmed by sequence analysis and their masses determined by MS analysis. The purified proteins reacted with antisera against related allergens from other species: Pru p 1 with antiserum to Bet v 1 and Pru p 3 with antiserum to Mal d 3 (from apple). The presence of secondary and tertiary structure was demonstrated by circular dichroism (CD) and high field NMR spectroscopy. CD spectroscopy also showed that the two proteins differed in their stability at pH 3 and in their ability to refold after heating to 95°C. Thus, Pru p 1 was unfolded at pH 3 even at 25°C but was able to refold after heating to 95°C at pH 7.5. In contrast, Pru p 3 was unable to refold after heating under neutral conditions but readily refolded after heating at pH 3. [source] UV-B-induced DNA damage and expression of defence genes under UV-B stress: tissue-specific molecular marker analysis in leavesPLANT CELL & ENVIRONMENT, Issue 9 2001G. Kalbin Abstract The aim of this study was to investigate the regulatory effect of ultraviolet-B (UV-B) radiation on a number of key stress response genes found in the epidermis and mesophyll of Pisum sativum L., Argenteum mutant. This mutant was chosen for the ease with which the entire epidermis can be removed from the mesophyll tissue. An additional goal was to explore the potential modifying effect of pre-acclimation of plants to UV-B radiation prior to exposure by UV-B during treatment. Results showed that mRNA accumulation was similar during acute short-term UV-B exposure for chalcone synthase (Chs) and short-chain alcohol dehydrogenase (SadA) in both epidermis and mesophyll. In contrast, the mRNA levels differed considerably between tissues for phenylalanine ammonia lyase, chalcone isomerase and lipid transfer protein. After 24 h incubation in visible light after cessation of UV-B exposure, the regulation of mRNA levels also differed between Chs and SadA, the former showing no expression in the epidermis and the latter none in the mesophyll. Acclimation to low UV-B levels before acute exposures resulted in delayed induction of Chs and SadA. Measurements of UV-B-induced cyclobutane pyrimidine dimers (CPDs) showed a greater formation in epidermis than in mesophyll. In addition, acclimation at low UV-B levels resulted in significantly higher basal levels of CPDs than in non-acclimated plants in both mesophyll and epidermis and also in increased damage in concomitant acute exposures. The lack of correlation between the number of CPDs and levels of transcripts for defence genes, indicates that DNA damage does not control transcription of these genes. [source] The structure and dynamics in solution of Cu(I) pseudoazurin from Paracoccus pantotrophusPROTEIN SCIENCE, Issue 5 2000Gary S. Thompson Abstract The solution structure and backbone dynamics of Cu(I) pseudoazurin, a 123 amino acid electron transfer protein from Paracoccus pantotrophus, have been determined using NMR methods. The structure was calculated to high precision, with a backbone RMS deviation for secondary structure elements of 0.35 ± 0.06 A, using 1,498 distance and 55 torsion angle constraints. The protein has a double-wound Greek-key fold with two ,-helices toward its C-terminus, similar to that of its oxidized counterpart determined by X-ray crystallography. Comparison of the Cu(I) solution structure with the X-ray structure of the Cu(II) protein shows only small differences in the positions of some of the secondary structure elements. Order parameters S2, measured for amide nitrogens, indicate that the backbone of the protein is rigid on the picosecond to nanosecond timescale. [source] Lack of genetic association between cholesteryl ester transfer protein and Japanese sporadic Alzheimer's diseasePSYCHOGERIATRICS, Issue 4 2006Akiyoshi KITAJIMA Abstract Background:, Cholesteryl ester transfer protein regulates the plasma high density lipoprotein cholesterol level, which is considered to play an antiatherogenic role in humans. The presence of apolipoprotein E epsilon4 allele is a strong risk factor for developing Alzheimer's disease (AD). Since apolipoprotein E is a regulator of lipid metabolism, it is reasonable to assume that lipids play important roles in the pathogenesis of AD. Methods:, We studied the relationship between polymorphisms of the cholesteryl ester transfer protein gene and risk for AD, analyzing two common polymorphisms of the gene and the relationship between them and plasma cholesterol level control samples. Results:, These polymorphisms showed no association with risk for AD. In rs5882, there was no significant difference in the mean plasma cholesterol concentrations found between patients with the A/A, A/G and G/G genotype. For rs2303790, no significant difference in the mean baseline cholesterol concentrations was found between patients with the A/A genotype and carriers of the G allele. Conclusion:, Our study indicates that these polymorphisms, rs5882 and rs2303790 were not associated with risk for AD. We also pointed out that these two polymorphisms do not affect plasma cholesterol levels in our Japanese AD samples. [source] Functional association of cell death suppressor, Arabidopsis Bax inhibitor-1, with fatty acid 2-hydroxylation through cytochrome b5THE PLANT JOURNAL, Issue 1 2009Minoru Nagano Summary Bax inhibitor-1 (BI-1) is a widely conserved cytoprotective protein localized in the endoplasmic reticulum (ER) membrane. We identified Arabidopsis cytochrome b5 (AtCb5) as an interactor of Arabidopsis BI-1 (AtBI-1) by screening the Arabidopsis cDNA library with the split-ubiquitin yeast two-hybrid (suY2H) system. Cb5 is an electron transfer protein localized mainly in the ER membrane. In addition, a bimolecular fluorescence complementation (BiFC) assay and fluorescence resonance energy transfer (FRET) analysis confirmed that AtBI-1 interacted with AtCb5 in plants. On the other hand, we found that the AtBI-1-mediated suppression of cell death in yeast requires Saccharomyces cerevisiae fatty acid hydroxylase 1 (ScFAH1), which had a Cb5-like domain at the N terminus and interacted with AtBI-1. ScFAH1 is a sphingolipid fatty acid 2-hydroxylase localized in the ER membrane. In contrast, AtFAH1 and AtFAH2, which are functional ScFAH1 homologues in Arabidopsis, had no Cb5-like domain, and instead interacted with AtCb5 in plants. These results suggest that AtBI-1 interacts with AtFAHs via AtCb5 in plant cells. Furthermore, the overexpression of AtBI-1 increased the level of 2-hydroxy fatty acids in Arabidopsis, indicating that AtBI-1 is involved in fatty acid 2-hydroxylation. [source] Plastid ,3-fatty acid desaturase-dependent accumulation of a systemic acquired resistance inducing activity in petiole exudates of Arabidopsis thaliana is independent of jasmonic acidTHE PLANT JOURNAL, Issue 1 2008Ratnesh Chaturvedi Summary Systemic acquired resistance (SAR) is an inducible defense mechanism that is activated throughout the plant, subsequent to localized inoculation with a pathogen. The establishment of SAR requires translocation of an unknown signal from the pathogen-inoculated leaf to the distal organs, where salicylic acid-dependent defenses are activated. We demonstrate here that petiole exudates (PeXs) collected from Arabidopsis leaves inoculated with an avirulent (Avr) Pseudomonas syringae strain promote resistance when applied to Arabidopsis, tomato (Lycopersicum esculentum) and wheat (Triticum aestivum). Arabidopsis FATTY ACID DESATURASE7 (FAD7), SUPPRESSOR OF FATTY ACID DESATURASE DEFICIENCY1 (SFD1) and SFD2 genes are required for accumulation of the SAR-inducing activity. In contrast to Avr PeX from wild-type plants, Avr PeXs from fad7, sfd1 and sfd2 mutants were unable to activate SAR when applied to wild-type plants. However, the SAR-inducing activity was reconstituted by mixing Avr PeXs collected from fad7 and sfd1 with Avr PeX from the SAR-deficient dir1 mutant. Since FAD7, SFD1 and SFD2 are involved in plastid glycerolipid biosynthesis and SAR is also compromised in the Arabidopsis monogalactosyldiacylglycerol synthase1 mutant we suggest that a plastid glycerolipid-dependent factor is required in Avr PeX along with the DIR1- encoded lipid transfer protein for long-distance signaling in SAR. FAD7 -synthesized lipids provide fatty acids for synthesis of jasmonic acid (JA). However, co-infiltration of JA and methylJA with Avr PeX from fad7 and sfd1 did not reconstitute the SAR-inducing activity. In addition, JA did not co-purify with the SAR-inducing activity confirming that JA is not the mobile signal in SAR. [source] Cuticular defects lead to full immunity to a major plant pathogenTHE PLANT JOURNAL, Issue 6 2007Céline Chassot Summary In addition to its role as a barrier, the cuticle is also a source of signals perceived by invading fungi. Cuticular breakdown products have been shown previously to be potent inducers of cutinase or developmental processes in fungal pathogens. Here the question was addressed as to whether plants themselves can perceive modifications of the cuticle. This was studied using Arabidopsis thaliana plants with altered cuticular structure. The expression of a cell wall-targeted fungal cutinase in A. thaliana was found to provide total immunity to Botrytis cinerea. The response observed in such cutinase-expressing plants is independent of signal transduction pathways involving salicylic acid, ethylene or jasmonic acid. It is accompanied by the release of a fungitoxic activity and increased expression of members of the lipid transfer protein, peroxidase and protein inhibitor gene families that provide resistance when overexpressed in wild-type plants. The same experiments were made in the bodyguard (bdg) mutant of A. thaliana. This mutant exhibits cuticular defects and remained free of symptoms after inoculation with B. cinerea. The expression of resistance was accompanied by the release of a fungitoxic activity and increased expression of the same genes as observed in cutinase-expressing plants. Structural defects of the cuticle can thus be converted into an effective multi-factorial defence, and reveal a hitherto hidden aspect of the innate immune response of plants. [source] Differential retention of ,-vitamin E is correlated with its transporter gene expression and growth inhibition efficacy in prostate cancer cellsTHE PROSTATE, Issue 5 2007Jing Ni Abstract BACKGROUND Epidemiological studies showed Vit E has protective effects against prostate cancer (PCa). Interestingly, different prostate cancer cells have different sensitivity to ,-Vit E or VES treatment. The goal of this study is to determine whether cellular Vit E bioavailability and its transport proteins are important contributing factors. METHODS ,-Vit E and its ester form, VES, were used to treat prostate cancer LNCaP, PC3, and DU145 cells, and their growth rates were determined by MTT assay. Cellular levels of Vit E were quantified using HPLC as the index of bioavailability. The expression levels of Vit E transport proteins were determined by real-time PCR. RESULTS Among these PCa cells, only LNCaP cells were sensitive to 20 µM ,-Vit E treatment, while both LNCaP and PC3 cells were sensitive to 20 µM VES treatment. Coordinately, cellular levels of ,-Vit E and VES positively correlated to their inhibitory effects. Further study found expression levels of Vit E transport proteins, including tocopherol associated protein (TAP), scavenger receptor class B type I (SR-BI), ,-tocopherol transfer protein (TTP), and ATP binding cassette transporter A1 (ABCA1), were different in various PCa cells, which may contribute to cellular Vit E bioavailability. This notion is further supported by the findings that overexpression or knockdown of TTP could coordinately alter cellular ,-Vit E levels in PCa cells. CONCLUSION Antiproliferative efficacy of ,-Vit E is correlated with its cellular bioavailability in PCa cells. Modulating the expression of the efflux or influx transporters could sensitize the growth inhibition efficacy of Vit E in prostate cancer cells. Prostate 67: 463,471, 2007. © 2007 Wiley-Liss, Inc. [source] Liver gene expression in relation to hepatic steatosis and lipid secretion in two duck speciesANIMAL GENETICS, Issue 1 2010F. Hérault Summary The susceptibility to development of hepatic steatosis is known to differ between Muscovy and Pekin ducks. Although some experiments were conducted to decipher these differences, few data have been produced to analyse the role of specific genes in this process. For this purpose, expression levels of genes involved in lipid (ATP citrate lyase, malic enzyme 1, fatty acid synthase, stearoyl-CoA desaturase 1, diacylglycerol O-acyl transferase 2, microsomal triglyceride transfer protein, apolipoprotein A1, apolipoprotein B, sterol regulatory element binding factor 1, hepatocyte nuclear factor 4, choline/ethanolamine phosphotransferase 1, carnitine palmitoyl transferase 1A, peroxisome proliferator-activated receptor alpha and sterol O-acyltransferase) and carbohydrate (activating transcription factor 4 or cAMP-response element binding protein, mitochondrial malate dehydrogenase 2 and carbohydrate responsive element binding protein) metabolism and in other functions were analysed in the liver of Pekin and Muscovy ducks fed ad libitum or overfed. A specific positive effect of feeding was observed on the expression of genes involved mainly in fatty acids and TG synthesis and glycolysis, and negative effect on genes involved in ,-oxidation. Interestingly, a strong species effect was also observed on stearoyl-CoA desaturase 1 and to a lesser extent on diacylglycerol O-acyl transferase 2 expression, leading to large differences in expression levels between Pekin and Muscovy overfed ducks, which could explain the difference in lipid metabolism and steatosis ability observed between the two duck species. These results should shed light on gene expression that might underlie susceptibility to hepatic steatosis in humans. [source] A non-synonymous mutation in a conserved site of the MTTP gene is strongly associated with protein activity and fatty acid profile in pigsANIMAL GENETICS, Issue 6 2009J. Estellé Summary Despite the economic interest of the fatty acid profile in pigs, no gene has been convincingly associated with this trait so far. Here, the porcine microsomal triglyceride transfer protein (MTTP) gene, which plays a crucial role in the assembly of nascent lipoproteins, has been analysed as a positional candidate gene for a QTL affecting the fatty acid composition that was previously identified on chromosome 8 in an Iberian by Landrace F2 cross. By resequencing a panel of different breeds, a non-synonymous polymorphism in a conserved residue of the lipid transfer domain of MTTP was identified. Association analyses with this polymorphism showed a strong association with the fatty acid composition of porcine fat, much stronger than the QTL effect, in the F2 cross and in a synthetic Sino-European line. In addition, in vitro activity assays in liver protein extracts have shown that this mutation is also associated with the lipid transfer activity of the MTTP protein (P < 0.1). These results suggest that the detected polymorphism is a potential causal factor of the fatty acid composition QTL. There appears to be an interaction between the porcine MTTP genotype and the type of fat source in the pig diet, which would agree with the previous results on the biology of MTTP biology. [source] | |||||||||||||||||||||||||||||||