Mol Microbiol . 2012 Mar 8; Konovalova A, Löbach S, Søgaard-Andersen L Proteolytic cleavage of precursor proteins to generate intercellular signals is a common mechanism in all cells.
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Philos Trans R Soc Lond B Biol Sci . 2012 Apr 19; 367(1592): 1047-58 Long F, Su CC, Lei HT, Bolla JR, Do SV, Yu EW Gram-negative bacteria frequently expel toxic chemicals through tripartite efflux pumps that span both the inner and outer membranes. The three parts are the inner membrane, substrate-binding transporter (or pump); a periplasmic membrane fusion protein (MFP, or adaptor); and an outer membrane-anchored channel. More: Philos Trans R Soc Lond B Biol Sci . 2012 Apr 19; 367(1592): 1047-58 Long F, Su CC, Lei HT, Bolla JR, Do SV, Yu EW Gram-negative bacteria frequently expel toxic chemicals through tripartite efflux pumps that span both the inner and outer membranes. The three parts are the inner membrane, substrate-binding transporter (or pump); a periplasmic membrane fusion protein (MFP, or adaptor); and an outer membrane-anchored channel. Follow this link: Biomol NMR Assign . 2012 Mar 14; Malki I, Cardoso de Amorim G, Simenel C, Prochnicka-Chalufour A, Delepierre M, Izadi-Pruneyre N TonB-dependent transporters (TBDTs) are bacterial outer membrane proteins that internalize nutrients such as vitamin B12, metal complexes, heme, some carbohydrates, etc. In addition to their transport activity, several TBDTs are also involved in a signalling cascade from the cell surface into the cytoplasm, via their periplasmic signalling domain.
PLoS One. 2012; 7(3): e32874 Activation-induced cell death is a natural process that prevents tissue damages from over-activated immune cells. TNF-Related apoptosis ligand (TRAIL), a TNF family member, induces apoptosis of infected and tumor cells by binding to one of its two death receptors, DR4 or DR5. TRAIL was reported to be secreted by phytohemagglutinin (PHA)-stimulated CD4(+) T cells in microvesicles.We investigate here TRAIL and DR5 regulation by activated primary CD4(+) T cells and its consequence on cell death. We observed that PHA induced CD4(+) T cell apoptosis in a dose-dependent manner. Thus, we investigated molecules involved in PHA-mediated cell death and demonstrated that TRAIL and DR5 were over-expressed on the plasma membrane of PHA-stimulated CD4(+) T cells. Surprisingly, DR5 was constitutively expressed in naive CD4(+) T cells at messenger RNA (mRNA) and protein levels. Thus, using 3 dimensional microscopy and intracellular staining assays, we show that DR5 is constitutively expressed in CD4(+) T cells and is pre-stocked in the cytoplasm. When cells are stimulated by PHA, DR5 is relocalized from cytoplasm to plasma membrane. Small interference RNA (siRNA) and blocking antibody assays demonstrate that TRAIL/DR5 interaction is mainly responsible for PHA-mediated CD4(+) T cell apoptosis. Thus, membrane DR5 expression leading to TRAIL-mediated apoptosis may represent one of the pathways responsible for eradication of over-activated CD4(+) T cells during immune responses. See the original post: J Microbiol Biotechnol . 2012 Feb; 22(2): 234-8 Khodi S, Latifi AM, Saadati M, Mirzaei M, Aghamollaei H Recombinant Escherichia coli displaying organophosphorus hydrolase (OPH) was used to overcome the diffusion barrier limitation of organophosphorus pesticides. Microbiology . 2012 Feb 16; Reimmann CE Iron uptake and transcriptional regulation by the enantiomeric siderophores pyochelin (Pch) and enantio-pyochelin (EPch) of Pseudomonas aeruginosa and Pseudomonas fluorescens, respectively, are stereospecific processes. The iron-loaded forms of Pch (ferriPch) and of EPch (ferriEPch) are recognized stereospecifically (i) at the outer membrane by the siderophore receptors FptA in P. Originally posted here: Microbiology . 2012 Feb 16; Reimmann CE Iron uptake and transcriptional regulation by the enantiomeric siderophores pyochelin (Pch) and enantio-pyochelin (EPch) of Pseudomonas aeruginosa and Pseudomonas fluorescens, respectively, are stereospecific processes. The iron-loaded forms of Pch (ferriPch) and of EPch (ferriEPch) are recognized stereospecifically (i) at the outer membrane by the siderophore receptors FptA in P
Free Radic Biol Med. 2012 Feb 1; Paraoxonase-1 (PON1) is a high-density lipoprotein (HDL)-associated serum enzyme thought to make a major contribution to the antioxidant and anti-inflammatory capacities of HDLs. However, the role of PON1 in the modulation of cholesterol efflux is poorly understood. The aim of our study was to investigate the involvement of PON1 in the regulation of cholesterol efflux, especially the mechanism by which it modulates HDL-mediated cholesterol transport. The enrichment of HDL(3) with human PON1 enhanced, in a dose-dependent manner, cholesterol efflux from THP-1 macrophage-like cells and ABCA1-enriched J774 macrophages. Moreover, an additive effect was observed when ABCA1-enriched J774 macrophages were incubated with both PON1 and apo-AI. Interestingly, PON1 alone was able to mediate cholesterol efflux from J774 macrophages and to upregulate ABCA1 expression on J774 macrophages. Immunofluorescence measurement showed an increase in PON1 levels in the cytoplasm of J774 macrophages overexpressing ABCA1. PON1 used an apo-AI-like mechanism to modulate cholesterol efflux from rapid and slow efflux pools derived from the lipid raft and nonraft domains of the plasma membrane, respectively. This was supported by the fact that ABCA1 protein was incrementally expressed by J774 macrophages within the first few hours of incubation with cholesterol-loaded J774 macrophages and that cyclodextrin significantly inhibited the capacity of PON1 to modulate cholesterol efflux from macrophages. This finding suggested that PON1 plays an important role in the antiatherogenic properties of HDLs and may exert its protective function outside the lipoprotein environment. Hum Vaccin Immunother . 2012 Mar 1; 8(3): Sizemore D, Warner E, Lawrence J, Thomas LJ, Roland K, Killeen K Preclinical studies evaluating plague vaccine candidates have demonstrated that the F1 and V antigen proteins of Yersinia pestis provide protection against challenge from virulent strains. Live-attenuated ΔphoP/Q Salmonella typhimurium recombinants expressing either F1, V antigen, F1 plus V antigen, or a F1-V fusion from Asd (+) balanced-lethal plasmids were constructed See more here: Hum Vaccin Immunother . 2012 Mar 1; 8(3): Sizemore D, Warner E, Lawrence J, Thomas LJ, Roland K, Killeen K Preclinical studies evaluating plague vaccine candidates have demonstrated that the F1 and V antigen proteins of Yersinia pestis provide protection against challenge from virulent strains. Go here to read the rest:
EMBO J. 2012 Feb 10; Formation of trans-acting small interfering RNAs (ta-siRNAs) from the TAS3 precursor is triggered by the AGO7/miR390 complex, which primes TAS3 for conversion into double-stranded RNA by the RNA-dependent RNA polymerase RDR6 and SGS3. These ta-siRNAs control several aspects of plant development. The mechanism routing AGO7-cleaved TAS3 precursor to RDR6/SGS3 and its subcellular organization are unknown. We show that AGO7 accumulates together with SGS3 and RDR6 in cytoplasmic siRNA bodies that are distinct from P-bodies. siRNA bodies colocalize with a membrane-associated viral protein and become positive for stress-granule markers upon stress-induced translational repression, this suggests that siRNA bodies are membrane-associated sites of accumulation of mRNA stalled during translation. AGO7 congregates with miR390 and SGS3 in membranes and its targeting to the nucleus prevents its accumulation in siRNA bodies and ta-siRNA formation. AGO7 is therefore required in the cytoplasm and membranous siRNA bodies for TAS3 processing, revealing a hitherto unknown role for membrane-associated ribonucleoparticles in ta-siRNA biogenesis and AGO action in plants. Read the original: PLoS One . 2012; 7(1): e30767 Nakamura Y, Kitamura N, Shinogi D, Yoshida M, Goda O, Murai R, Kamino H, Arakawa H Mieap, a p53-inducible protein, controls mitochondrial quality by repairing unhealthy mitochondria. During repair, Mieap induces the accumulation of intramitochondrial lysosomal proteins (designated MALM for Mieap-induced accumulation of lysosome-like organelles within mitochondria) by interacting with NIX, leading to the elimination of oxidized mitochondrial proteins Read the original: PLoS One . 2012; 7(1): e30767 Nakamura Y, Kitamura N, Shinogi D, Yoshida M, Goda O, Murai R, Kamino H, Arakawa H Mieap, a p53-inducible protein, controls mitochondrial quality by repairing unhealthy mitochondria. During repair, Mieap induces the accumulation of intramitochondrial lysosomal proteins (designated MALM for Mieap-induced accumulation of lysosome-like organelles within mitochondria) by interacting with NIX, leading to the elimination of oxidized mitochondrial proteins. Read the original here: |
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