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By admin, on May 14th, 2012
Comp Biochem Physiol A Mol Integr Physiol. 2012 May 2;
Notch EG, Chapline C, Flynn E, Lameyer T, Lowell A, Sato D, Shaw JR, Stanton BA
The Atlantic killifish (Fundulus heteroclitus) is an environmental sentinel organism used extensively for studies of environmental toxicants and osmoregulation. Previous research in our laboratory has shown that acute acclimation to seawater is mediated by an increase in SGK1. SGK1 promotes the trafficking of CFTR chloride channels from intracellular vesicles to the plasma membrane of the gill within the first hour in seawater resulting in increased chloride secretion. Although we have shown that the increase in gill SGK1 does not require activation of the glucocorticoid receptor, the mechanisms that mediate the rise SGK1 during acute acclimation is unknown. To test the hypothesis that mitogen activated protein kinase (MAPK14) is responsible for the rise in SGK1 we identified the coding sequence of killifish MAPK14-1 and designed a translational blocking vivo-morpholino targeting MAPK14-1. Injection of the MAPK14-1 vivo-morpholino resulted in a 30% reduction of MAPK14-1 and a 45% reduction in phosphorylated-MAPK14-1 protein in the gill of killifish transitioned from freshwater to seawater. Knock down of phosphorlyated-MAPK14-1 completely blocked the rise in SGK1 mRNA and protein in the killifish gill, providing the first direct and in vivo evidence that MAPK14-1 is necessary for acute seawater acclimation.
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Mitogen activated protein kinase 14-1 regulates serum glucocorticoid kinase 1 during seawater acclimation in Atlantic killifish, Fundulus heteroclitus.
By admin, on May 12th, 2012
S.flexneri is a Gram-negative pathogen, which infects the host by virulence protein via all kinds of secretion system. So far, six kinds of secretion systems have been found. Though they are distinctive in secretion beaus and …
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Identification of Virulence-related Membrane Protein Complex from …
By admin, on May 12th, 2012
S.flexneri is a Gram-negative pathogen, which infects the host by virulence protein via all kinds of secretion system. So far, six kinds of secretion systems have been found. Though they are distinctive in secretion beaus and …
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Identification of Virulence-related Membrane Protein Complex from …
By admin, on May 5th, 2012
Mol Biol Cell. 2012 May 2;
Curwin AJ, von Blume J, Malhotra V
The mechanism of cargo sorting at the trans-Golgi network (TGN) for secretion is poorly understood. We have previously reported the involvement of the actin severing protein cofilin, and the Ca(2+)ATPase SPCA1 in sorting of soluble secretory cargo at the TGN in mammalian cells. Now we report that cofilin in yeast is required for export of selective secretory cargo at the late Golgi membranes. In cofilin mutant (cof1-8) cells, the cell wall protein Bgl2 was secreted at a reduced rate and retained in a late Golgi compartment, while the plasma membrane H(+)ATPase Pma1, which is transported in the same class of carriers reached the cell surface. Additionally, sorting of CPY to the vacuole was delayed and CPY was secreted from cof1-8 cells. Loss of the yeast ortholog of SPCA1 (Pmr1) exhibited similar sorting defects and displayed synthetic sickness with cof1-8. Additionally, overexpression of PMR1 restored Bgl2 secretion in cof1-8 cells. These findings highlight the conserved role of cofilin and SPCA1/Pmr1 in sorting of the soluble secretory proteins at the TGN/late Golgi membranes in eukaryotes.
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Cofilin mediated sorting and export of specific cargo from the Golgi apparatus in yeast.
By admin, on May 5th, 2012
Mol Biol Cell. 2012 May 2;
Curwin AJ, von Blume J, Malhotra V
The mechanism of cargo sorting at the trans-Golgi network (TGN) for secretion is poorly understood. We have previously reported the involvement of the actin severing protein cofilin, and the Ca(2+)ATPase SPCA1 in sorting of soluble secretory cargo at the TGN in mammalian cells. Now we report that cofilin in yeast is required for export of selective secretory cargo at the late Golgi membranes. In cofilin mutant (cof1-8) cells, the cell wall protein Bgl2 was secreted at a reduced rate and retained in a late Golgi compartment, while the plasma membrane H(+)ATPase Pma1, which is transported in the same class of carriers reached the cell surface. Additionally, sorting of CPY to the vacuole was delayed and CPY was secreted from cof1-8 cells. Loss of the yeast ortholog of SPCA1 (Pmr1) exhibited similar sorting defects and displayed synthetic sickness with cof1-8. Additionally, overexpression of PMR1 restored Bgl2 secretion in cof1-8 cells. These findings highlight the conserved role of cofilin and SPCA1/Pmr1 in sorting of the soluble secretory proteins at the TGN/late Golgi membranes in eukaryotes.
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Cofilin mediated sorting and export of specific cargo from the Golgi apparatus in yeast.
By admin, on May 2nd, 2012
Infect Immun . 2012 Apr 30; Tapia-Pastrana G, Chavez-Dueñas L, Lanz-Mendoza H, Teter K, Navarro-Garcia F Despite the autotransporter (AT) moniker, AT secretion appears to involve the function of periplasmic chaperones.
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VirK is a Periplasmic Protein Required for Efficient Secretion of Pet from Enteroaggregative E. coli.
By admin, on May 2nd, 2012
Infect Immun . 2012 Apr 30; Tapia-Pastrana G, Chavez-Dueñas L, Lanz-Mendoza H, Teter K, Navarro-Garcia F Despite the autotransporter (AT) moniker, AT secretion appears to involve the function of periplasmic chaperones. We identified four periplasmic proteins that specifically bound to plasmid-encoded toxin (Pet), an AT produced by enteroaggregative Escherichia coli (EAEC).
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VirK is a Periplasmic Protein Required for Efficient Secretion of Pet from Enteroaggregative E. coli.
By admin, on April 25th, 2012
PLoS One . 2012; 7(4): e35453 Rosenberger T, Brülle JK, Sander P Protein secretion is essential for all bacteria in order to interact with their environment. Mycobacterium tuberculosis depends on protein secretion to subvert host immune response mechanisms.
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A β-Lactamase Based Reporter System for ESX Dependent Protein Translocation in Mycobacteria.
By admin, on April 24th, 2012
J Biol Chem . 2012 Apr 20; Wang X, Pineau C, Gu S, Guschinskaya N, Pickersgill RW, Shevchik VE The type II secretion system (T2SS) secretes enzymes and toxins across the outer membrane of Gram-negative bacteria. The precise assembly of T2SS, which consists of at least twelve core-components called Gsp, remains unclear
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Cysteine scanning mutagenesis and disulfide mapping analysis of the arrangement of GspC and GspD protomers within the T2SS.
By admin, on April 22nd, 2012
Environ Toxicol Chem . 2012 Apr 17; Hancock DE, Indest KJ, Gust KA, Kennedy A Rapid advances are being made in the creation and use of nanomaterials, but little is known about the impact these materials might have on key microbial functions if introduced into the environment. Previous studies have generated conflicting results with respect to the impact of fullerenes on microbial activity.
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Effects of C(60) on the Salmonella typhimurium TA100 transcriptome expression: Insights into C(60) -mediated growth inhibition and mutagenicity.
By admin, on April 17th, 2012
BMC Immunol. 2012 Apr 14; 13(1): 19
Gonzalez Y, Herrera MT, Soldevila G, Garcia-Garcia L, Perez-Armendariz EM, Fabian G, Bobadilla K, Guzman-Beltran S, Sada E, Torres M
ABSTRACT: BACKGROUND: CD33 is a membrane receptor containing a lectin domain and a cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM) that is able to inhibit cytokine production. CD33 is expressed by monocytes, and reduced expression of CD33 correlates with augmented production of inflammatory cytokines, such as IL-1beta, TNF-alpha, and IL-8. However, the role of CD33 in the inflammation associated with hyperglycemia and diabetes is unknown. Therefore, we studied CD33 expression and inflammatory cytokine secretion in freshly isolated monocytes from patients with type 2 diabetes. To evaluate the effects of hyperglycemia, monocytes from healthy donors were cultured with different glucose concentrations (15-50 mmol/l D-glucose), and CD33 expression and inflammatory cytokine production were assessed. The expression of suppressor of cytokine signaling protein-3 (SOCS-3) and the generation of reactive oxygen species (ROS) were also evaluated to address the cellular mechanisms involved in the down-regulation of CD33. RESULTS: CD33 expression was significantly decreased in monocytes from patients with type 2 diabetes, and higher levels of TNF-alpha, IL-8 and IL-12p70 were detected in the plasma of patients compared to healthy donors. Under high glucose conditions, CD33 protein and mRNA expression was significantly decreased, whereas spontaneous TNF-alpha secretion and SOCS-3 mRNA expression were increased in monocytes from healthy donors. Furthermore, the down-regulation of CD33 and increase in TNF-alpha production were prevented when monocytes were treated with the antioxidant alpha-tocopherol and cultured under high glucose conditions. CONCLUSION: Our results suggest that hyperglycemia down-regulates CD33 expression and triggers the spontaneous secretion of TNF-alpha by peripheral monocytes. This phenomenon involves the generation of ROS and the up-regulation of SOCS-3. These observations support the importance of blood glucose control for maintaining innate immune function and suggest the participation of CD33 in the inflammatory profile associated with type 2 diabetes.
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High glucose concentrations induce TNF-alpha production through the down-regulation of CD33 in primary human monocytes.
By admin, on April 7th, 2012
Nat Rev Microbiol . 2012 Apr 2; Korotkov KV, Sandkvist M, Hol WG Many Gram-negative bacteria use the sophisticated type II secretion system (T2SS) to translocate a wide range of proteins from the periplasm across the outer membrane. The inner-membrane platform of the T2SS is the nexus of the system and orchestrates the secretion process through its interactions with the periplasmic filamentous pseudopilus, the dodecameric outer-membrane complex and a cytoplasmic secretion ATPase
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The type II secretion system: biogenesis, molecular architecture and mechanism.
By admin, on April 6th, 2012
Nat Struct Mol Biol . 2012 Apr 1; Selkrig J, Mosbahi K, Webb CT, Belousoff MJ, Perry AJ, Wells TJ, Morris F, Leyton DL, Totsika M, Phan MD, Celik N, Kelly M, Oates C, Hartland EL, Robins-Browne RM, Ramarathinam SH, Purcell AW, Schembri MA, Strugnell RA, Henderson IR, Walker D, Lithgow T Bacteria have mechanisms to export proteins for diverse purposes, including colonization of hosts and pathogenesis. A small number of archetypal bacterial secretion machines have been found in several groups of bacteria and mediate a fundamentally distinct secretion process
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Discovery of an archetypal protein transport system in bacterial outer membranes.
By admin, on April 6th, 2012
Nat Struct Mol Biol . 2012 Apr 1; Selkrig J, Mosbahi K, Webb CT, Belousoff MJ, Perry AJ, Wells TJ, Morris F, Leyton DL, Totsika M, Phan MD, Celik N, Kelly M, Oates C, Hartland EL, Robins-Browne RM, Ramarathinam SH, Purcell AW, Schembri MA, Strugnell RA, Henderson IR, Walker D, Lithgow T Bacteria have mechanisms to export proteins for diverse purposes, including colonization of hosts and pathogenesis. A small number of archetypal bacterial secretion machines have been found in several groups of bacteria and mediate a fundamentally distinct secretion process
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Discovery of an archetypal protein transport system in bacterial outer membranes.
By admin, on April 5th, 2012
Infect Immun . 2012 Apr 2; Forbes SJ, Martinelli D, Hsieh C, Ault JG, Marko M, Mannella CA, Mantis NJ Invasion of intestinal epithelial cells by Salmonella enterica serovar Typhimurium is an energetically demanding process, involving the transfer of effector proteins from invading bacteria into host cells via a specialized organelle known as the SPI-1 type 3-secretion system (T3SS). By a mechanism that remains poorly understood, entry of S
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Association of a Protective Monoclonal IgA with the O-Antigen of Salmonella enterica serovar Typhimurium Impacts Type 3 Secretion and Outer Membrane Integrity.
By admin, on April 5th, 2012
Infect Immun . 2012 Apr 2; Forbes SJ, Martinelli D, Hsieh C, Ault JG, Marko M, Mannella CA, Mantis NJ Invasion of intestinal epithelial cells by Salmonella enterica serovar Typhimurium is an energetically demanding process, involving the transfer of effector proteins from invading bacteria into host cells via a specialized organelle known as the SPI-1 type 3-secretion system (T3SS). By a mechanism that remains poorly understood, entry of S
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Association of a Protective Monoclonal IgA with the O-Antigen of Salmonella enterica serovar Typhimurium Impacts Type 3 Secretion and Outer Membrane Integrity.
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