scholarly journals Comparison of S-layer secretion genes in freshwater caulobacters

2004 ◽  
Vol 50 (9) ◽  
pp. 751-766 ◽  
Author(s):  
Mihai Iuga ◽  
Peter Awram ◽  
John F Nomellini ◽  
John Smit
Keyword(s):  
Protein Secretion ◽  
Caulobacter Crescentus ◽  
Sequence Similarity ◽  
Atp Binding ◽  
Type I ◽  
C Terminus ◽  
Expression Studies ◽  
Size Groups ◽  
Membrane Fusion Proteins ◽  
Atp Binding Cassette

Our freshwater caulobacter collection contains about 40 strains that are morphologically similar to Caulobacter crescentus. All elaborate a crystalline protein surface (S) layer made up of protein monomers 100–193 kDa in size. We conducted a comparative study of S-layer secretion in 6 strains representing 3 size groups of S-layer proteins: small (100–108 kDa), medium (122–151 kDa), and large (181–193 kDa). All contained genes predicted to encode ATP-binding cassette transporters and membrane fusion proteins highly similar to those of C. crescentus, indicating that the S-layer proteins were all secreted by a type I system. The S-layer proteins' C-termini showed unexpectedly low sequence similarity but contained conserved residues and predicted secondary structure features typical of type I secretion signals. Cross-expression studies showed that the 6 strains recognized secretion signals from C. crescentus and Pseudomonas aeruginosa and similarly that C. crescentus was able to secrete the S-layer protein C-terminus of 1 strain examined. Inactivation of the ATP-binding cassette transporter abolished S-layer protein secretion, indicating that the type I transporter is necessary for S-layer protein secretion. Finally, while all of the S-layer proteins of this subset of strains were secreted by type I mechanisms, there were significant differences in genome positions of the transporter genes that correlated with S-layer protein size.Key words: freshwater caulobacter, S-layer, type I secretion system, ABC transporter.

scholarly journals Expression of an ATP-binding cassette transporter-encoding gene (YOR1) is required for oligomycin resistance in Saccharomyces cerevisiae.

1995 ◽  
Vol 15 (12) ◽  
pp. 6875-6883 ◽  
Author(s):  
D J Katzmann ◽  
T C Hallstrom ◽  
M Voet ◽  
W Wysock ◽  
J Golin ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fusion Gene ◽  
Sequence Similarity ◽  
Yeast Cells ◽  
Atp Binding ◽  
Zinc Cluster ◽  
Atp Binding Cassette Transporter ◽  
Transporter Family ◽  
Encoding Gene ◽  
Atp Binding Cassette

Semidominant mutations in the PDR1 or PDR3 gene lead to elevated resistance to cycloheximide and oligomycin. PDR1 and PDR3 have been demonstrated to encode zinc cluster transcription factors. Cycloheximide resistance mediated by PDR1 and PDR3 requires the presence of the PDR5 membrane transporter-encoding gene. However, PDR5 is not required for oligomycin resistance. Here, we isolated a gene that is necessary for PDR1- and PDR3-mediated oligomycin resistance. This locus, designated YOR1, causes a dramatic elevation in oligomycin resistance when present in multiple copies. A yor1 strain exhibits oligomycin hypersensitivity relative to an isogenic wild-type strain. In addition, loss of the YOR1 gene blocks the elevation in oligomycin resistance normally conferred by mutant forms of PDR1 or PDR3. The YOR1 gene product is predicted to be a member of the ATP-binding cassette transporter family of membrane proteins. Computer alignment indicates that Yor1p shows striking sequence similarity with multidrug resistance-associated protein, Saccharomyces cerevisiae Ycf1p, and the cystic fibrosis transmembrane conductance regulator. Use of a YOR1-lacZ fusion gene indicates that YOR1 expression is responsive to PDR1 and PDR3. While PDR5 expression is strictly dependent on the presence of PDR1 or PDR3, control of YOR1 expression has a significant PDR1/PDR3-independent component. Taken together, these data indicate that YOR1 provides the link between transcriptional regulation by PDR1 and PDR3 and oligomycin resistance of yeast cells.

scholarly journals Effects of Astaxanthin on Reverse Cholesterol Transport and Atherosclerosis in Mice

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Tang-Bin Zou ◽  
Shan-Shan Zhu ◽  
Fei Luo ◽  
Wei-Qiao Li ◽  
Xue-Rong Sun ◽  
...  
Keyword(s):  
Reverse Cholesterol Transport ◽  
Scavenger Receptor ◽  
Hdl Cholesterol ◽  
High Plasma ◽  
Cholesterol Transport ◽  
Atp Binding ◽  
Type I ◽  
Aortic Sinus ◽  
Atp Binding Cassette Transporter ◽  
Atp Binding Cassette

High plasma level of HDL-cholesterol (HDL-C) has been consistently associated with a decreased risk of atherosclerosis (AS); thus, HDL-C is considered to be an antiatherogenic lipoprotein. The development of novel therapies to enhance the atheroprotective properties of HDL may have the possibility of further reducing the residual AS risk. Reverse cholesterol transport (RCT) is believed to be a primary atheroprotective activity of HDL, which has been shown to promote the efflux of excess cholesterol from macrophage-derived foam cells via ATP-binding cassette transporter A1 (ABCA1), ATP-binding cassette transporter G1 (ABCG1), and scavenger receptor class B type I (SR-BI) and then transport it back to the liver for excretion into bile and eventually into the feces. In the current study, we investigated the effects of astaxanthin on RCT and AS progression in mice. The results showed that short- and long-term supplementation of astaxanthin promote RCT in C57BL/6J and ApoE−/−mice, respectively. Moreover, astaxanthin can relieve the plaque area of the aortic sinus and aortic cholesterol in mice. These findings suggest that astaxanthin is beneficial for boosting RCT and preventing the development of AS.

scholarly journals Contributions of Aspergillus fumigatus ATP-Binding Cassette Transporter Proteins to Drug Resistance and Virulence

2013 ◽  
Vol 12 (12) ◽  
pp. 1619-1628 ◽  
Author(s):  
Sanjoy Paul ◽  
Daniel Diekema ◽  
W. Scott Moye-Rowley
Keyword(s):  
Drug Resistance ◽  
Aspergillus Fumigatus ◽  
Abc Transporter ◽  
Abc Transporters ◽  
Sequence Similarity ◽  
Atp Binding ◽  
Content Type ◽  
Transporter Proteins ◽  
Encoding Genes ◽  
Atp Binding Cassette

ABSTRACTIn yeast cells such as those ofSaccharomyces cerevisiae, expression of ATP-binding cassette (ABC) transporter proteins has been found to be increased and correlates with a concomitant elevation in azole drug resistance. In this study, we investigated the roles of twoAspergillus fumigatusproteins that share high sequence similarity withS. cerevisiaePdr5, an ABC transporter protein that is commonly overproduced in azole-resistant isolates in this yeast. The twoA. fumigatusgenes encoding the ABC transporters sharing the highest sequence similarity toS. cerevisiaePdr5 are calledabcAandabcBhere. We constructed deletion alleles of these two different ABC transporter-encoding genes in three different strains ofA. fumigatus. Loss ofabcBinvariably elicited increased azole susceptibility, whileabcAdisruption alleles had variable phenotypes. Specific antibodies were raised to both AbcA and AbcB proteins. These antisera allowed detection of AbcB in wild-type cells, while AbcA could be visualized only when overproduced from thehspApromoter inA. fumigatus. Overproduction of AbcA also yielded increased azole resistance. Green fluorescent protein fusions were used to provide evidence that both AbcA and AbcB are localized to the plasma membrane inA. fumigatus. Promoter fusions to firefly luciferase suggested that expression of both ABC transporter-encoding genes is inducible by azole challenge. Virulence assays implicated AbcB as a possible factor required for normal pathogenesis. This work provides important new insights into the physiological roles of ABC transporters in this major fungal pathogen.

scholarly journals The Caulobacter crescentus Paracrystalline S-Layer Protein Is Secreted by an ABC Transporter (Type I) Secretion Apparatus

1998 ◽  
Vol 180 (12) ◽  
pp. 3062-3069 ◽  
Author(s):  
Peter Awram ◽  
John Smit
Keyword(s):  
Abc Transporter ◽  
Transport System ◽  
Protein Transport ◽  
Caulobacter Crescentus ◽  
Sequence Similarity ◽  
Secretion System ◽  
Cell Protein ◽  
Type I ◽  
Secretion Systems ◽  
Secretion Signal

ABSTRACT Caulobacter crescentus is a gram-negative bacterium that produces a two-dimensional crystalline array on its surface composed of a single 98-kDa protein, RsaA. Secretion of RsaA to the cell surface relies on an uncleaved C-terminal secretion signal. In this report, we identify two genes encoding components of the RsaA secretion apparatus. These components are part of a type I secretion system involving an ABC transporter protein. These genes, lying immediately 3′ of rsaA, were found by screening a Tn5 transposon library for the loss of RsaA transport and characterizing the transposon-interrupted genes. The two proteins presumably encoded by these genes were found to have significant sequence similarity to ABC transporter and membrane fusion proteins of other type I secretion systems. The greatest sequence similarity was found to the alkaline protease (AprA) transport system ofPseudomonas aeruginosa and the metalloprotease (PrtB) transport system of Erwinia chrysanthemi. TheprtB and aprA genes were introduced intoC. crescentus, and their products were secreted by the RsaA transport system. Further, defects in the S-layer protein transport system led to the loss of this heterologous secretion. This is the first report of an S-layer protein secreted by a type I secretion apparatus. Unlike other type I secretion systems, the RsaA transport system secretes large amounts of its substrate protein (it is estimated that RsaA accounts for 10 to 12% of the total cell protein). Such levels are expected for bacterial S-layer proteins but are higher than for any other known type I secretion system.

Scavenger receptor class B type I mediates biliary cholesterol secretion independent of ATP-binding cassette transporter g5/g8 in mice

Hepatology ◽  
2009 ◽  
Vol 50 (4) ◽  
pp. 1263-1272 ◽  
Author(s):  
Harmen Wiersma ◽  
Alberto Gatti ◽  
Niels Nijstad ◽  
Ronald P. J. Oude Elferink ◽  
Folkert Kuipers ◽  
...  
Keyword(s):  
Scavenger Receptor ◽  
Atp Binding ◽  
Type I ◽  
Biliary Cholesterol ◽  
Atp Binding Cassette Transporter ◽  
Scavenger Receptor Class ◽  
Class B ◽  
Biliary Cholesterol Secretion ◽  
Cholesterol Secretion ◽  
Atp Binding Cassette

scholarly journals Berberine Improves High-Fat Diet Induced Atherosclerosis and Hepatic Steatosis in Apoe-/-Mice by Down-Regulating PCSK9 via ERK1/2 Pathway

2020 ◽  
Author(s):  
Chun-Yan Ma ◽  
Xiao-Yun Shi ◽  
Ya-Ru Wu ◽  
Yue Zhang ◽  
Hui-Lin Qu ◽  
...  
Keyword(s):  
Western Blotting ◽  
High Fat Diet ◽  
Hepg2 Cells ◽  
Density Lipoprotein ◽  
Atp Binding ◽  
Type I ◽  
High Fat ◽  
Atp Binding Cassette Transporter ◽  
Atp Binding Cassette

Abstract Background:Berberine (BBR) is a kind of alkaloid derived from Chinese herbal medicine, which has multiple pharmacological activities including anti-atherosclerosis (AS). However, the mechanism underlying the role of BBR in modulating lipid metabolic disorders is not fully clear. The aim of the present study was to investigate the beneficial effects of BBR on AS in ApoE-/- mice and its potential mechanisms.Methods: Eight-week old ApoE-/- mice with high-fat diet (HFD) and wild type mice were administered eitherBBR (50mg/kg/d and 100mg/kg/d, respectively) or equivoluminal saline. After the 16-week treatment, the blood was collected for lipid evaluation, and aorta and liver were obtained from the mice for hematoxylin-eosin (HE) staining, oil red O staining and Western blotting. HepG2 Cells were treated by BBR (0, 5, 25, and 50 μg/ml) for 24 hours. Real-time PCR or Western blotting was used to examine the expression levels of proprotein convertase subtilisin/kexin type 9 (PCSK9), LDL receptor (LDLR), ATP-binding cassette transporter A1(ABCA1), ATP-binding cassette transporter G1(ABCG1) and scavenger receptor class B type I(SR-BI).Results: BBR significantly decreased serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) cholesterol (LDL-C) and increased high-density lipoprotein cholesterol (HDL-C) level in ApoE-/- mice fed with HFD. Moreover, BBR markedly reduced aorta atheroscleroticplaque, ameliorated lipid deposition in the liver in vivo. BBR could also promote intracellular cholesterol efflux and regulate LDLR and PCSK9 expression via the ERK1/2 pathway in HepG2 cells.Conclusions: BBR could improve lipid metabolism, decrease aorta AS and hepatic lipid accumulation in ApoE-/- mice fed with HFD, which was associated with down-regulation of PCSK9 through ERK1/2 pathway.

scholarly journals Residues of a proposed gate region in type I ATP-binding cassette import systems are crucial for function as revealed by mutational analysis

2013 ◽  
Vol 1828 (9) ◽  
pp. 2164-2172 ◽  
Author(s):  
Daniela Weidlich ◽  
Nicole Wiesemann ◽  
Johanna Heuveling ◽  
Kristina Wardelmann ◽  
Heidi Landmesser ◽  
...  
Keyword(s):  
Mutational Analysis ◽  
Atp Binding ◽  
Type I ◽  
Gate Region ◽  
Atp Binding Cassette
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