Lipids of
            <i>Salmonella typhimurium</i>
            and
            <i>Escherichia coli:</i>
            Structure and Metabolism

Ames, Giovanna Ferro‐Luzzi

doi:10.1128/jb.95.3.833-843.1968

Cited by 584 publications

(196 citation statements)

References 39 publications

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“…In the liposome system, the membrane binding of NSP1 required the presence of negatively charged phospholipids such as PS, which is a major lipid in the cytoplasmic leaflet of eukaryotic membranes where NSP1 normally is localized (Peränen et al, 1995;Laakkonen et al, 1996). However, in the membranes of E.coli, the most abundant negatively charged phospholipids are PG and CL, whereas PS is present only in trace amounts (Ames, 1968). PG was also effective in mediating the binding of NSP1 to liposomes, so it may have the same activity in attaching NSP1 to the bacterial plasma membrane.…”

Section: Discussionmentioning

confidence: 99%

Semliki Forest virus mRNA capping enzyme requires association with anionic membrane phospholipids for activity

Ahola¹,

et al. 1999

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The replication complexes of all positive strand RNA viruses of eukaryotes are associated with membranes. In the case of Semliki Forest virus (SFV), the main determinant of membrane attachment seems to be the virus-encoded non-structural protein NSP1, the capping enzyme of the viral mRNAs, which has guanine-7-methyltransferase and guanylyltransferase activities. We show here that both enzymatic activities of SFV NSP1 are inactivated by detergents and reactivated by anionic phospholipids, especially phosphatidylserine. The region of NSP1 responsible for binding to membranes as well as to liposomes was mapped to a short segment, which is conserved in the large alphavirus-like superfamily of viruses. A synthetic peptide of 20 amino acids from the putative binding site competed with in vitro synthesized NSP1 for binding to liposomes containing phosphatidylserine. These findings suggest a molecular mechanism by which RNA virus replicases attach to intracellular membranes and why they depend on the membranous environment.

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Section: Discussionmentioning

confidence: 99%

Semliki Forest virus mRNA capping enzyme requires association with anionic membrane phospholipids for activity

Ahola¹,

et al. 1999

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“…Total membrane lipid from approx. 1.5 mg membrane protein, determined by the Lowry method [33], was extracted by the Bligh and Dyer method [34] as modified in [35]. Ster01s were separated from phospholipids by silicic acid chromatography [19].…”

Section: Determination Of Sterol/phospholipid Ratio and Fatty Acidmentioning

confidence: 99%

Polyunsaturated fatty acids alter sterol transbilayer domains in LM fibroblast plasma membrane

Sweet

Schroeder

1988

FEBS Letters

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Sterols are asymmetrically distributed between the leaflets of animal cell plasma membranes. Although transbilayer migration of sterols is extremely rapid, s to rain, previous experimental manipulations have not altered their transmembrane steady-state distribution. However, the effect of polyunsaturated fatty acids has not been reported. When cultured in a lipid-free, chemically defined culture medium, LM fibroblasts do not synthesize polyunsaturated fatty acids but will incorporate polyunsaturated fatty acids into their plasma membranes if supplied in the medium. Sterol transbilayer distribution in LM plasma membranes was determined from quenching of fluorescence of dehydroergosterol by trinitrophenyl groups selectively attached to the exofacial leaflet. When cells are cultured in lipid-free media, 28.1% of the plasma membrane sterol is located in the exofacial (outside) leaflet. In contrast, when cells are cultured with linoleate-or linolenatesupplemented medium, 71 ;8% and 75.5% of the plasma membrane sterol is exofacial, respectively.

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“…Phospholipids were extracted from Crithidia fasciculata as detailed elsewhere [27,28]. Proteoliposomes were prepared by mixing equimolar amounts of parasite membrane antigens with isolated phospholipids in the presence of octyl glucoside or Zwittergent 3.12 [lo].…”

Section: Isolation Of Parasite Antigens and Formation Of Proteoliposomesmentioning

confidence: 99%

The macrophage-attachment glycoprotein gp63 is the predominant C3-acceptor site on Leishmania mexicana promastigotes

Russell

1987

Eur J Biochem

105

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The interaction between Leishmania promastigotes and their vertebrate host's complement system results not only in parasite lysis but also, due to surface-bound complement components, in increased macrophage binding potential. In this study we demonstrate, with the use of isolated complement components, that activation is via the alternative complement pathway, initiated by direct deposition of C3 onto the parasite surface. The predominant C3 acceptor site on the promastigotes was intitially identified as the glycoprotein gp63 by anti-C3 antibody immunoprecipitation of radioiodinated promastigotes following incubation in the alternative pathway initiators C3, and factors B and D. The C3-binding properties of gp63 were confirmed and quantified, in relation to other surface antigens, by incubating parasites in iodinated C3 and immunoprecipitating bound C3 with antibodies directed against different promastigote surface antigens. The other abundant surface antigen, the glycolipid 'excreted factor', did not show any C3-binding activity. Further demonstration was provided by incubating liposomes containing either gp63 or excreted factor in iodinated C3 and factors B and D. Only gp63-containing liposomes bound C3. Considering that both gp63 and the excreted factor have recently been implicated in attachment and uptake by macrophage, these findings may have considerable bearing in the determination of which of the macrophage surface receptors identify which parasite ligand.Leishmania is an obligate intracellular parasite living within the macrophage of its vertebrate hosts. Transmission is effected when the promastigote form of the parasite is introduced via the wound made by a feeding sandfly. During this initial period, prior to the successful establishment of an infection, the parasite is particularly vulnerable to the host's anti-microbial defences. It has long been known that the host's complement system is capable of causing lysis of the promastigotes form [l] and although most researches believe lysis is via the alternative pathway, i. e. antibody-independent [2, 31, similar experimental procedures have produced conflicting results [4]. A conclusive demonstration of the mechanism of complement activation is therefore important.In addition, two recent reports indicate that attachment and uptake of the promastigotes form of Leishmania by macrophages is, at least in part, due to the activity of the macrophage CR3, the receptor for the membrane-bound form of C3 [5, 61. The type of macrophage receptor involved in parasite internalization is important because of the differential killing activity associated with the different surface receptors (see [7] activity [9] and would therefore be the receptor of choice for an aspiring intracellular parasite. On the promastigote surface two antigens have been shown to be involved in the attachment and uptake by macrophages; these are the glycoprotein gp63 [lo] and the glycolipid 'excreted factor' (EF) [ll]. Both appear to be conserved antigens present in a similar form on all s...

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Lipids of Salmonella typhimurium and Escherichia coli: Structure and Metabolism

Cited by 584 publications

References 39 publications

Semliki Forest virus mRNA capping enzyme requires association with anionic membrane phospholipids for activity

Semliki Forest virus mRNA capping enzyme requires association with anionic membrane phospholipids for activity

Polyunsaturated fatty acids alter sterol transbilayer domains in LM fibroblast plasma membrane

The macrophage-attachment glycoprotein gp63 is the predominant C3-acceptor site on Leishmania mexicana promastigotes

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