Determination of the Amino Acid Sequence of the Plant Cytolysin Enterolobin

Fontes, Wagner; Sousa, Marcelo Valle de; Aragão, Jeferson B.; Morhy, Lauro

doi:10.1006/abbi.1997.0358

Cited by 24 publications

(22 citation statements)

References 19 publications

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“…Its binding to receptor induces a proteolytic cleavage leading to an active form that oligomerizes, forming a channel that causes lysis of the target cell. For the first time identified in a mollusc, the proteins sharing this specific pore forming sequence motif have been identified mainly in bacteria but also in a few plants and cnidarians [73], [74], [75]. In cnidarians, the pore-forming toxin could be either a defensive or offensive allomone that is involved in protecting cnidarians against predators or in killing preys [75].…”

Section: Discussionmentioning

confidence: 99%

A Large Repertoire of Parasite Epitopes Matched by a Large Repertoire of Host Immune Receptors in an Invertebrate Host/Parasite Model

et al. 2010

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For many decades, invertebrate immunity was believed to be non-adaptive, poorly specific, relying exclusively on sometimes multiple but germ-line encoded innate receptors and effectors. But recent studies performed in different invertebrate species have shaken this paradigm by providing evidence for various types of somatic adaptations at the level of putative immune receptors leading to an enlarged repertoire of recognition molecules. Fibrinogen Related Proteins (FREPs) from the mollusc Biomphalaria glabrata are an example of these putative immune receptors. They are known to be involved in reactions against trematode parasites. Following not yet well understood somatic mechanisms, the FREP repertoire varies considerably from one snail to another, showing a trend towards an individualization of the putative immune repertoire almost comparable to that described from vertebrate adaptive immune system. Nevertheless, their antigenic targets remain unknown. In this study, we show that a specific set of these highly variable FREPs from B. glabrata forms complexes with similarly highly polymorphic and individually variable mucin molecules from its specific trematode parasite S. mansoni (Schistosoma mansoni Polymorphic Mucins: SmPoMucs). This is the first evidence of the interaction between diversified immune receptors and antigenic variant in an invertebrate host/pathogen model. The same order of magnitude in the diversity of the parasite epitopes and the one of the FREP suggests co-evolutionary dynamics between host and parasite regarding this set of determinants that could explain population features like the compatibility polymorphism observed in B. glabrata/S. mansoni interaction. In addition, we identified a third partner associated with the FREPs/SmPoMucs in the immune complex: a Thioester containing Protein (TEP) belonging to a molecular category that plays a role in phagocytosis or encapsulation following recognition. The presence of this last partner in this immune complex argues in favor of the involvement of the formed complex in parasite recognition and elimination from the host.

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Section: Discussionmentioning

confidence: 99%

A Large Repertoire of Parasite Epitopes Matched by a Large Repertoire of Host Immune Receptors in an Invertebrate Host/Parasite Model

et al. 2010

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“…GPI anchor glycans are essential for embryogenesis and skin development in mice (27), and GPI deficiencies cause paroxysmal nocturnal hemoglobinuria in humans (28). Moreover, GPI-anchored proteins are receptors for bacterial toxins, clostridial ␣-toxin (29), aerolysin (30), and the plant toxin enterolobin (31). Here we show a novel putative function of the GPI anchor glycan of CD48, namely, as an immunomodulator of the response to IL-18.…”

Section: Identification Of the Gpi-anchored Protein Involved In The Cmentioning

confidence: 91%

Functional Role Played by the Glycosylphosphatidylinositol Anchor Glycan of CD48 in Interleukin-18-induced Interferon-γ Production

Fukushima

Ikehara

Yamashita

2005

Journal of Biological Chemistry

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Interleukin (IL)-18 induces T cells and natural killer cells to produce not only interferon-␥ but also othercytokines by binding to the IL-18 receptor (IL-18R) ␣ and ␤ subunits. However, little is known about how IL-18, IL-18R␣, and IL-18R␤ form a high-affinity complex on the cell surface and transduce the signal. We found that IL-18 and IL-18R␣ bind to glycosylphosphatidylinositol (GPI) glycan via the third mannose 6-phosphate diester and the second ␤-GlcNAc-deleted mannose 6-phosphate of GPI glycan, respectively. To determine which GPIanchored glycoprotein is involved in the complex of IL-18 and IL-18R␣, IL-18R␣ of IL-18-stimulated KG-1 cells was immunoprecipitated together with CD48 by anti-IL-18R␣ antibody. More than 90% of CD48 was detected as ␤-GlcNAc-deleted GPI-anchored glycoprotein, and soluble recombinant human CD48 without GPI glycan bound to IL-18R␣, indicating that CD48 is associated with IL-18R␣ via both the peptide portion and the GPI glycan. To investigate whether the carbohydrate recognition of IL-18 is involved in physiological activities,

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“…AT belongs to a distinctive class of related cytolytic toxins whose prototype is aerolysin, secreted by the Gram-negative bacterium Aeromonas hydrophila (4). Interestingly, enterolobin, a cytolytic protein derived from the Brazilian Enterolobium contortisiliquum tree also appears to be related to aerolysin (5,6). The mechanisms of AT and aerolysin have been shown to be highly similar.…”

mentioning

confidence: 99%

“…Comparatively little is known about the cytolytic mechanism of enterolobin, but its primary structure appears to be more related to aerolysin than AT. Enterolobin displays sequence similarity with both the small and large lobes of aerolysin and appears to form a dimer in solution (6,16).…”

mentioning

confidence: 99%

The Identification and Structure of the Membrane-spanning Domain of the Clostridium septicum Alpha Toxin

Melton

Parker

Rossjohn

et al. 2004

Journal of Biological Chemistry

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Alpha toxin (AT) is a pore-forming toxin produced byClostridium septicum that belongs to the unique aerolysin-like family of pore-forming toxins. The location and structure of the transmembrane domains of these toxins have remained elusive. Using deletion mutagenesis, cysteine-scanning mutagenesis and multiple spectrofluorimetric methods a membrane-spanning amphipathic ␤-hairpin of AT has been identified. Spectrofluorimetric analysis of cysteine-substituted residues modified with an environmentally sensitive fluorescent probe via the cysteine sulfydryl showed that the side chains of residues 203-232 alternated between the aqueous milieu and the membrane core when the AT oligomer was inserted into membranes, consistent with the formation of an amphipathic transmembrane ␤-hairpin. AT derivatives that contained deletions that removed up to 90% of the ␤-hairpin did not form a pore but were similar to native toxin in all other aspects of the mechanism. Furthermore, a mutant of AT that contained an engineered disulfide, predicted to restrict the movement of the ␤-hairpin, functioned similarly to native toxin except that it did not form a pore unless the disulfide bond was reduced. Together these studies revealed the location and structure of the membrane-spanning domain of AT.

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Determination of the Amino Acid Sequence of the Plant Cytolysin Enterolobin

Cited by 24 publications

References 19 publications

A Large Repertoire of Parasite Epitopes Matched by a Large Repertoire of Host Immune Receptors in an Invertebrate Host/Parasite Model

A Large Repertoire of Parasite Epitopes Matched by a Large Repertoire of Host Immune Receptors in an Invertebrate Host/Parasite Model

Functional Role Played by the Glycosylphosphatidylinositol Anchor Glycan of CD48 in Interleukin-18-induced Interferon-γ Production

The Identification and Structure of the Membrane-spanning Domain of the Clostridium septicum Alpha Toxin

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