http://www.biomedcentral.com/bmcbiochem/ The editor's pick of recent articles published by BMC Biochemistry 2012-05-16T00:00:00Z Background: Nuclear factor kappa B (NF-kappaB) is a key transcription factor that plays a crucial role in hostsurvival during infection by pathogens. Therefore, it has been a priority of many pathogens tomanipulate the cellular NF-kappaB activity in order to create a favorable environment for theirsurvival inside the host. Results: We observed that heterologous expression of the open reading frame 2 (ORF2) protein inhuman hepatoma cells led to stabilization of the cellular I kappa B alpha (IkappaBalpha) pool, with aconcomitant reduction in the nuclear localization of the p65 subunit of NF-kappaB and inhibitionof NF-kappaB activity. Although basal or TPA induced phosphorylation of IkappaBalpha was not altered,its ubiquitination was markedly reduced in ORF2 expressing cells. Further analysis revealedthat ORF2 protein could directly associate with the F-box protein, beta transducin repeatcontaining protein (betaTRCP) and ORF2 over expression resulted in reduced association ofIkappaBalpha with the SKP1 and CUL1 components of the SCFbetaTRCP complex. Chromatinimmunoprecipitation (ChIP) assay of the proximal promoter regions of MHC-I heavy chainand IL-8 genes using p65 antibody and LPS stimulated ORF2 expressing cell extract revealeddecreased association of p65 with the above regions, indicating that ORF2 inhibited p65binding at endogenous promoters. Conclusions: In this report we suggest a mechanism by which ORF2 protein of HEV may inhibit host cellNF-kappaB activity during the course of a viral infection. http://www.biomedcentral.com/1471-2091/13/7 Milan Surjit Bhavna Varshney Sunil K Lal BMC Biochemistry 2012, 13:7 2012-05-16T00:00:00Z 10.1186/1471-2091-13-7 How HEV inhibits NF-kB in human liver cells The open reading frame 2 glycoprotein of the hepatitis E virus (HEV) inhibits nuclear factor kappa B (NF-kB), which is crucial to host survival, by blocking degradation of cellular I kappa B alpha. /content/figures/1471-2091-13-7-toc.gif BMC Biochemistry 1471-2091 13 7 2012-05-16T00:00:00Z PDF Background: Bird species show a high degree of variation in the composition of their preen gland waxes. For instance, galliform birds like chicken contain fatty acid esters of 2,3-alkanediols, while Anseriformes like goose or Strigiformes like barn owl contain wax monoesters in their preen gland secretions. The final biosynthetic step is catalyzed by wax synthases (WS) which have been identified in pro- and eukaryotic organisms. Results: Sequence similarities enabled us to identify six cDNAs encoding putative wax synthesizing proteins in chicken and two from barn owl and goose. Expression studies in yeast under in vivo and in vitro conditions showed that three proteins from chicken performed WS activity while a sequence from chicken, goose and barn owl encoded a bifunctional enzyme catalyzing both wax ester and triacylglycerol synthesis. Mono- and bifunctional WS were found to differ in their substrate specificities especially with regard to branched-chain alcohols and acyl-CoA thioesters. According to the expression patterns of their transcripts and the properties of the enzymes, avian WS proteins might not be confined to preen glands. Conclusions: We provide direct evidence that avian preen glands possess both monofunctional and bifunctional WS proteins which have different expression patterns and WS activities with different substrate specificities. http://www.biomedcentral.com/1471-2091/13/4 Eva-Maria Biester Janine Hellenbrand Jens Gruber Mats Hamberg Margrit Frentzen BMC Biochemistry 2012, 13:4 2012-02-04T00:00:00Z 10.1186/1471-2091-13-4 Wax synthesizing enzymes identified in birds Homology searching of avian databases has identified wax synthase genes expressed in the bird preen gland; analysis of the expressed proteins confirms they are capable of catalysing wax synthesis. /content/figures/1471-2091-13-4-toc.gif BMC Biochemistry 1471-2091 13 4 2012-02-04T00:00:00Z XML Background: Enzymatic allergens of storage mites that contaminate stored food products are poorly characterized. We describe biochemical and immunological properties of the native alpha-amylase allergen Aca s 4 from Acarus siro, a medically important storage mite. Results: A. siro produced a high level of alpha-amylase activity attributed to Aca s 4. This enzyme was purified and identified by protein sequencing and LC-MS/MS analysis. Aca s 4 showed a distinct inhibition pattern and an unusual alpha-amylolytic activity with low sensitivity to activation by chloride ions. Homology modeling of Aca s 4 revealed a structural change in the chloride-binding site that may account for this activation pattern. Aca s 4 was recognized by IgE from house dust mite-sensitive patients, and potential epitopes for cross-reactivity with house dust mite group 4 allergens were found. Conclusions: We present the first protein-level characterization of a group 4 allergen from storage mites. Due to its high production and IgE reactivity, Aca s 4 is potentially relevant to allergic hypersensitivity. http://www.biomedcentral.com/1471-2091/13/3 Jana Pytelková Martin Lepšík Miloslav Šanda Pavel Talacko Lucie Marešová Michael Mareš BMC Biochemistry 2012, 13:3 2012-01-31T00:00:00Z 10.1186/1471-2091-13-3 Allergenic Acarus activity The first protein-level characterization of the group 4 alpha-amylase allergen Aca s 4 from the food storage mite Acarus siro reveals a distinct inhibition pattern and unusual alpha-amylolytic activity that may play an important role in allergenic hypersensitivity /content/figures/1471-2091-13-3-toc.gif BMC Biochemistry 1471-2091 13 3 2012-01-31T00:00:00Z XML Background: ATP-binding cassette transporter A1 (ABCA1) mediates the lipidation of exchangeable apolipoproteins, the rate-limiting step in the formation of high density lipoproteins (HDL). We previously demonstrated that HDL oxidized ex vivo by peroxidase-generated tyrosyl radical (tyrosylated HDL, tyrHDL) increases the availability of cellular cholesterol for efflux and reduces the development of atherosclerosis when administered to apolipoprotein E-deficient mice as compared to treatment with control HDL. Results: In the current study we determined that tyrHDL requires functional ABCA1 for this enhanced activity. Like lipid-free apolipoprotein A-I (apoA-I), tyrHDL increases total and cell surface ABCA1, inhibits calpain-dependent and -independent proteolysis of ABCA1, and can be bound by cell surface ABCA1 in human skin fibroblasts. Additionally, tyrHDL apoproteins are susceptible to digestion by enteropeptidase like lipid-free apoA-I, but unlike lipid-bound apoA-I on HDL, which is resistant to proteolysis. Conclusions: These results provide the first evidence that lipid-bound apolipoproteins on the surface of spherical HDL particles can behave like lipid-free apoA-I to increase ABCA1 protein levels and activity. http://www.biomedcentral.com/1471-2091/13/1 Mohammad A Hossain Sereyrath Ngeth Teddy Chan Michael N Oda Gordon A Francis BMC Biochemistry 2012, 13:1 2012-01-16T00:00:00Z 10.1186/1471-2091-13-1 Lipid-bound apolipoproteins enhance ABCA1 activity Lipid-bound apolipoproteins on the surface of spherical high density lipoprotein (HDL) particles can behave like lipid-free apolipoprotein A-I (apoA-I) to increase ATP-binding cassette transporter A1 (ABCA1) protein levels and activity. /content/figures/1471-2091-13-1-toc.gif BMC Biochemistry 1471-2091 13 1 2012-01-16T00:00:00Z XML Background: Birds clean and lubricate their feathers with waxes that are produced in the uropygial gland, a holocrine gland located on their back above the tail. The type and the composition of the secreted wax esters are dependent on the bird species, for instance the wax ester secretion of goose contains branched-chain fatty acids and unbranched fatty alcohols, whereas that of barn owl contains fatty acids and alcohols both of which are branched. Alcohol-forming fatty acyl-CoA reductases (FAR) catalyze the reduction of activated acyl groups to fatty alcohols that can be esterified with acyl-CoA thioesters forming wax esters. Results: cDNA sequences encoding fatty acyl-CoA reductases were cloned from the uropygial glands of barn owl (Tyto alba), domestic chicken (Gallus gallus domesticus) and domestic goose (Anser anser domesticus). Heterologous expression in Saccharomyces cerevisiae showed that they encode membrane associated enzymes which catalyze a NADPH dependent reduction of acyl-CoA thioesters to fatty alcohols. By feeding studies of transgenic yeast cultures and in vitro enzyme assays with membrane fractions of transgenic yeast cells two groups of isozymes with different properties were identified, termed FAR1 and FAR2. The FAR1 group mainly synthesized 1-hexadecanol and accepted substrates in the range between 14 and 18 carbon atoms, whereas the FAR2 group preferred stearoyl-CoA and accepted substrates between 16 and 20 carbon atoms. Expression studies with tissues of domestic chicken indicated that FAR transcripts were not restricted to the uropygial gland. Conclusion: The data of our study suggest that the identified and characterized avian FAR isozymes, FAR1 and FAR2, can be involved in wax ester biosynthesis and in other pathways like ether lipid synthesis. http://www.biomedcentral.com/1471-2091/12/64 Janine Hellenbrand Eva-Maria Biester Jens Gruber Mats Hamberg Margrit Frentzen BMC Biochemistry 2011, 12:64 2011-12-12T00:00:00Z 10.1186/1471-2091-12-64 Characterizing FARs from birds Fatty acyl-CoA reductases (FARs) cloned from the preening glands of barn owls, chickens and geese represent two distinct groups of isozymes that may be involved in wax ester biosynthesis and other pathways such as ether lipid synthesis /content/figures/1471-2091-12-64-toc.gif BMC Biochemistry 1471-2091 12 64 2011-12-12T00:00:00Z XML