Nucleotide sequence of the gene for the hole-forming toxin aerolysin of Aeromonas hydrophila

Howard, S. Peter; Garland, W J; Green, M J; Buckley, J. Thomas

doi:10.1128/jb.169.6.2869-2871.1987

Cited by 168 publications

(126 citation statements)

References 20 publications

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“…It has previously been shown that proaerolysin, in contrast to aerolysin, is essentially inactive against erythrocytes (13). The observation that CHO cells are highly sensitive to the protoxin suggested that they express a protease(s) able to convert the protoxin to the active form that is not present or not capable of activating the protoxin in erythrocytes.…”

Section: Furin and Other Members Of The Proprotein Convertase Family mentioning

confidence: 98%

“…The protein is released as a soluble dimeric precursor (6,7) that can bind to specific receptors on target cells (8 -12). Proaerolysin must be activated by proteolytic cleavage (13), which releases a C-terminal peptide (14) and leads to a change in secondary structure (15). This enables the next step in channel formation, which is the generation of a heptameric oligomer (16,17).…”

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confidence: 99%

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The Pore-forming Toxin Proaerolysin Is Activated by Furin

Abrami¹,

Fivaz²,

Decroly³

et al. 1998

Journal of Biological Chemistry

143

120

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Aerolysin is secreted as an inactive dimeric precursor by the bacterium Aeromonas hydrophila. Proteolytic cleavage within a mobile loop near the C terminus of the protoxin is required for oligomerization and channel formation. This loop contains the sequence KVRRAR 432 , which should be recognized by mammalian proprotein convertases such as furin, PACE4, and PC5/6A. Here we show that these three proteases cleave proaerolysin after Arg-432 in vitro, yielding active toxin. We also investigated the potential role of these enzymes in the in vivo activation of the protoxin. We found that Chinese hamster ovary cells were able to convert the protoxin to aerolysin in the absence of exogenous proteases and that activation did not require internalization of the toxin. The furin inhibitor ␣ 1 -antitrypsin Portland reduced the rate of proaerolysin activation in vivo, and proaerolysin processing was even further reduced in furin-deficient FD11 Chinese hamster ovary cells. The cells were also less sensitive to proaerolysin than wild type cells; however, transient transfection of FD11 cells with the cDNA encoding furin conferred normal sensitivity to the protoxin. Together these findings argue that furin catalyzes the cell-surface activation of proaerolysin in vivo.Many toxins are secreted by pathogenic organisms as inactive precursors, presumably to protect the producing cells from self-destruction or to increase the efficiency of delivery to the target cells. Activation of toxin precursors often involves proteolytic processing by enzymes produced either by the pathogen itself or by the host organism. The identification of these proteases may be crucial to our understanding of the pathogenesis of the organism.Aerolysin is a virulence factor secreted by the human pathogen Aeromonas hydrophila (Refs. 1-3, for review see Refs. 4 and 5). The protein is released as a soluble dimeric precursor (6, 7) that can bind to specific receptors on target cells (8 -12). Proaerolysin must be activated by proteolytic cleavage (13), which releases a C-terminal peptide (14) and leads to a change in secondary structure (15). This enables the next step in channel formation, which is the generation of a heptameric oligomer (16,17). Being amphipathic (18), the heptamer can insert into the membrane thereby producing well defined channels (19). In the case of erythrocytes, channel formation leads to cell lysis; however, depending upon the toxin concentration, nucleated cells may undergo a number of changes before death occurs. These include loss of small molecules and ions through the aerolysin channels, vacuolation of the endoplasmic reticulum (12), or even apoptosis. 1 We have shown that activation of proaerolysin with trypsin is due to cleavage at the carboxyl side of Lys-427 2 (20), which is located in an 18-amino acid surface-exposed flexible loop (21). This loop also contains the sequence K 427 VRRAR 432 which corresponds to one of the motifs recognized by furin-like endoproteases, also called proprotein convertases (PC), suggesting that proaero...

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Section: Furin and Other Members Of The Proprotein Convertase Family mentioning

confidence: 98%

mentioning

confidence: 99%

The Pore-forming Toxin Proaerolysin Is Activated by Furin

Abrami¹,

Fivaz²,

Decroly³

et al. 1998

Journal of Biological Chemistry

143

120

View full text Add to dashboard Cite

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“…Aerolysin is secreted by Aeromonas spp. as an inactive dimeric precursor that is activated by proteolytic removal of about 40 amino acids from the C-terminus [6,7]. The toxin is concentrated on the surface of target cells by binding to a specific receptor [8].…”

Section: Introductionmentioning

confidence: 99%

Characterisation of the heptameric pore‐forming complex of the Aeromonas toxin aerolysin using MALDI‐TOF mass spectrometry

Moniatte¹,

Goot

Buckley

et al. 1996

FEBS Letters

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Aerolysin, a virulence factor secreted by Aeromonas hydrophila, is representative of a group of ~-sheet toxins that must form stable homooligomers in order to be able to insert into biological membranes and generate channels. Electron microscopy and image analysis of two-dimensional membrane crystals had previously revealed a structure with 7-fold symmetry suggesting that aerolysin forms heptameric oligomers [Wilmsen et al. (1992) EMBO J. 11, 2457-24631. However, this unusual molecularity of the channel remained to be confirmed by an independent method since low-resolution electron crystallography had led to artefactual data for other pore-forming toxins. In this study, matrix-assisted laser desorption/ionization time-offlight mass spectrometry (MALDI-TOF-MS) was used to measure the mass of the aerolysin oligomer preparation. A mass of 333 850 Da was measured, fitting very well with a beptameric complex (expected mass: 332 300 Da). These results confirm the earlier evidence that the aerolysin oligomer is a heptamer and also show that MALDI-TOF mass spectrometry could be a valuable tool to study non-covalent association of proteins.

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“…It crosses the inner bacterial membrane as preprotoxin containing signal peptide sequences, which is removed from the N-terminus and activated by proteolytic removal of nearly 25 amino acid from the C-terminus. The active aerolysin protein binds to the specifi c glycophosphatidylinositol (GPI)-anchored proteins on the target surface of eukaryotic red blood cells and forms pores in the cell membrane causing lysis [1,2]. Aerolysin is signifi cant and a stable molecular marker to detect the possible virulent A. hydrophila.…”

Section: Introductionmentioning

confidence: 99%

Detection of aerolysin gene in Aeromonas hydrophila isolated from fish and pond water

et al. 2008

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Aerolysin is a hemolytic toxin encoded by aerolysin gene (1482 bp) that plays a key role in the pathogenesis of Aeromonas hydrophila infection in fi sh. New speciesspecifi c primers were designed to amplify 326 bp conserved region of aerolysin gene for A. hydrophila. Twenty-fi ve isolates of A. hydrophila recovered from fi sh and pond water were studied for detection of aerolysin gene. Aerolysin gene was detected in 85% of the isolates during the study. The designed primers were highly specifi c and showed no cross reactivity with Escherichia coli, Aeromonas veronii, Vibrio cholerae, Flavobacterium spp., Chyseobacterium spp. and Staphylococcus aureus. The sensitivity limit of primers for detection of aerolysin gene in the genomic DNA of A. hydrophila was 5 pg.

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Nucleotide sequence of the gene for the hole-forming toxin aerolysin of Aeromonas hydrophila

Abstract: The gene for the hole-forming toxin aerolysin from Aeromonas hydrophila was sequenced. Although most of the sequence seems unrelated to that of Staphylococcus aureus alpha-toxin, both proteins are very hydrophilic, and they each contain a nearly identical string of 10 amino acids.

Cited by 168 publications

References 20 publications

The Pore-forming Toxin Proaerolysin Is Activated by Furin

The Pore-forming Toxin Proaerolysin Is Activated by Furin

Characterisation of the heptameric pore‐forming complex of the Aeromonas toxin aerolysin using MALDI‐TOF mass spectrometry

Detection of aerolysin gene in Aeromonas hydrophila isolated from fish and pond water

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