Hemolysin E (HlyE, ClyA, SheA) and Related Toxins

  • Stuart Hunt
  • Jeffrey Green
  • Peter J. Artymiuk
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 677)


Certain strains of Escherichia coli, Salmonella enterica and Shigella flexneri produce a pore-forming toxin hemolysin E (HlyE), also known as cytolysin A (ClyA) and silent hemolysin, locus A (SheA). HlyE lyses erythrocytes and mammalian cells, forming transmembrane pores with a minimum internal diameter of ∼25 Å. We review the current knowledge of HlyE structure and function in its solution and pore forms, models for membrane insertion, its potential use in biotechnology applications and its relationship to a wider superfamily of toxins.


Bacillus Cereus Color Version Membrane Binding Membrane Insertion Tail Domain 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. 1.
    del Castillo FJ, Leal SC, Moreno F et al. The Escherichia coli K-12 sheA gene encodes a 34-kDa secreted haemolysin. Mol Microbiol 1997; 25:107–115.PubMedCrossRefGoogle Scholar
  2. 2.
    Green J, Baldwin ML. The molecular basis for the differential regulation of the hlyE-encoded haemolysin of Escherichia coli by FNR and HlyX lies in the improved Activating Region 1 contact of HlyX. Microbiology 1997; 143:3785–3793.PubMedCrossRefGoogle Scholar
  3. 3.
    Ludwig A, Bauer S, Benz R et al. Analysis of the SlyA-controlled expression, subcellular localization and pore-forming activity of a 34 kDa haemolysin (ClyA) from Escherichia coli K-12. Mol Microbiol 1999; 31:557–567.PubMedCrossRefGoogle Scholar
  4. 4.
    Ludwig A, von Rhein C, Bauer S et al. Molecular analysis of cytolysin a (ClyA) in pathogenic Escherichia coli strains. J Bacteriol 2004; 186:5311–5320.PubMedCrossRefGoogle Scholar
  5. 5.
    Oscarsson J, Mizunoe Y, Uhlin BE et al. Induction of haemolytic activity in Escherichia coli by the slyA gene product. Mol Microbiol 1996; 20:191–199.PubMedCrossRefGoogle Scholar
  6. 6.
    Oscarsson J, Westermark M, Lofdahl S et al. Characterization of a pore-forming cytotoxin expressed by Salmonella enterica serovars Typhi and Paratyphi A. Infect Immun 2002; 70:5759–5769.PubMedCrossRefGoogle Scholar
  7. 7.
    Lai XH, Arencibia I, Johansson A et al. Cytocidal and apoptotic effects of the ClyA protein from Escherichia coli on primary and cultured monocytes and macrophages. Infect Immun 2000; 68:4363–4367.PubMedCrossRefGoogle Scholar
  8. 8.
    Soderblom T, Oxhamre C, Wai SN et al. Effects of the Escherichia coli toxin cytolysin A on mucosal immunostimulation via epithelial Ca2??signalling and Toll-like receptor 4. Cell Microbiol 2005; 7:779–788.PubMedCrossRefGoogle Scholar
  9. 9.
    Wallace AJ, Stillman TJ, Atkins A et al. E. coli hemolysin E (HlyE, ClyA, SheA): X-ray crystal structure of the toxin and observation of membrane pores by electron microscopy. Cell 2000; 100:265–276.PubMedCrossRefGoogle Scholar
  10. 10.
    Reingold J, Starr N, Maurer J et al. Identification of a new Escherichia coli She haemolysin homolog in avian E. coli. Vet Microbiol 1999; 66:125–134.PubMedCrossRefGoogle Scholar
  11. 11.
    Nagai S, Yagihashi T, Ishihama A. An avian pathogenic Escherichia coli strain produces a hemolysin, the expression of which is dependent on cyclic AMP receptor protein gene function. Vet Microbiol 1998; 60:227–238.PubMedCrossRefGoogle Scholar
  12. 12.
    Coote JG. Structural and functional relationships among the RTX toxin determinants of Gram negative bacteria. FEMS Microbiol Rev 1992; 88:137–162.CrossRefGoogle Scholar
  13. 13.
    Kerenyi M, Allison HE, Batai I et al. Occurrence of hlyA and sheA genes in extraintestinal Escherichia coli strains. J Clin Microbiol 2005; 43(6):2965–2968.PubMedCrossRefGoogle Scholar
  14. 14.
    Faucher SP, Forest C, Beland M et al. A novel PhoP-regulated locus encoding the cytolysin ClyA and the secreted invasin TaiA of Salmonella enterica serovar Typhi is involved in virulence. Microbiology 2009; 155:477–488.PubMedCrossRefGoogle Scholar
  15. 15.
    von Rhein C, Hunfeld KP, Ludwig A. Serologic evidence for effective production of cytolysin A in Salmonella enterica serovars Typhi and Paratyphi A during human infection. Infect Immun 2006; 74:6505–6508.CrossRefGoogle Scholar
  16. 16.
    von Rhein C, Bauer S, Sanjurjo EJL et al. ClyA cytolysin from Salmonella: Distribution within the genus, regulation of expression by SlyA and pore-forming characteristics. Int J Med Microbiol 2009; 299:21–35.CrossRefGoogle Scholar
  17. 17.
    Highet AR, Berry AM, Bettelheim KA et al. The frequency of molecular detection of virulence genes encoding cytolysin A, high-pathogenicity island and cytolethal distending toxin of Escherichia coli in cases of sudden infant death syndrome does not differ from that in other infant deaths and healthy infants. J Med Microbiol 2009; 58:285–289.PubMedCrossRefGoogle Scholar
  18. 18.
    von Rhein C, Bauer S, Simon V et al. Occurrence and characteristics of the cytolysin A gene in Shigella strains and other members of the family Enterobacteriaceae. FEMS Microbiol Lett 2008; 287:143–148.CrossRefGoogle Scholar
  19. 19.
    Wyborn NR, Stapleton MR, Norte VA et al. Regulation of Escherichia coli hemolysin E expression by H-NS and Salmonella SlyA. J Bacteriol 2004; 186:1620–1628.PubMedCrossRefGoogle Scholar
  20. 20.
    Westermark M, Oscarsson J, Mizunoe Y et al. Silencing and activation of ClyA cytotoxin expression in Escherichia coli. J Bacteriol 2000; 182:6347–6357.PubMedCrossRefGoogle Scholar
  21. 21.
    Lithgow JK, Haider F, Roberts IS et al. Alternate SlyA and H-NS nucleoprotein complexes control hlyE expression in Escherichia coli K-12. Mol Microbiol 2007; 66:685–698.PubMedCrossRefGoogle Scholar
  22. 22.
    Zhao G, Weatherspoon N, Kong W et al. A dual-signal regulatory circuit activates transcription of a set of divergent operons in Salmonella typhimurium. Proc Natl Acad Sci USA 2008; 105:20924–20929.PubMedCrossRefGoogle Scholar
  23. 23.
    Atkins A, Wyborn NR, Wallace AJ et al. Structure-function relationships of a novel bacterial toxin, hemolysin E—The role of alpha(G). J Biol Chem 2000; 275:41150–41155.PubMedCrossRefGoogle Scholar
  24. 24.
    Oscarsson J, Mizunoe Y, Li L et al. Molecular analysis of the cytolytic protein ClyA (SheA) from Escherichia coli. Mol Microbiol 1999; 32:1226–1238.PubMedCrossRefGoogle Scholar
  25. 25.
    Wai SN, Lindmark B, Soederblom T et al. Vesicle-mediated export and assembly of pore-forming oligomers of the enterobacterial ClyA cytotoxin. Cell 2003; 115:25–35.PubMedCrossRefGoogle Scholar
  26. 26.
    Eifler N, Vetsch M, Gregorini M et al. Cytotoxin ClyA from Escherichia coli assembles to a 13-meric pore independent of its redox-state. EMBO J 2006; 25:2652–2661.PubMedCrossRefGoogle Scholar
  27. 27.
    Tzokov SB, Wyborn NR, Stillman TJ et al. Structure of the hemolysin E (HlyE, ClyA and SheA) channel in its membrane-bound form. J Biol Chem 2006; 281:23042–23049.PubMedCrossRefGoogle Scholar
  28. 28.
    Hunt S, Moir AJG, Tzokov S et al. The formation and structure of Escherichia coli K-12 haemolysin E pores. Microbiology 2008; 154:633–642.PubMedCrossRefGoogle Scholar
  29. 29.
    Parker MW, Feil SC. Pore-forming protein toxins: from structure to function. Prog Biophys Mol Biol 2005; 88:91–142.PubMedCrossRefGoogle Scholar
  30. 30.
    Dong CJ, Beis K, Nesper J et al. Wza the translocon for E. coli capsular polysaccharides defines a new class of membrane protein. Nature 2006; 444:226–229.PubMedCrossRefGoogle Scholar
  31. 31.
    Mueller M, Grauschkopf U, Maier T et al. The structure of a cytolytic alpha-helical toxin pore reveals its assembly mechanism. Nature 2009; 459:726–730.PubMedCrossRefGoogle Scholar
  32. 32.
    Wyborn NR, Clark A, Roberts RE et al. Properties of haemolysin E (HlyE) from a pathogenic Escherichia coli avian isolate and studies of HlyE export. Microbiology 2004; 150:1495–1505.PubMedCrossRefGoogle Scholar
  33. 33.
    Ludwig A, Tengel C, Bauer S et al. SlyA, a regulatory protein from Salmonella typhimurium, induces a haemolytic and pore-forming protein in Escherichia coli. Mol Gen Genet 1995; 249:474–486.PubMedCrossRefGoogle Scholar
  34. 34.
    del Castillo FJ, Moreno F, del Castillo I. Secretion of the Escherichia coli K-12 sheA hemolysin is independent of its cytolytic activity. FEMS Microbiol Lett 2001; 204:281–285.PubMedCrossRefGoogle Scholar
  35. 35.
    Galen JE, Zhao LC, Chinchilla M et al. Adaptation of the endogenous Salmonella enterica serovar typhi clyA-encoded hemolysin for antigen export enhances the immunogenicity of anthrax protective antigen domain 4 expressed by the attenuated live-vector vaccine strain CVD 908-htrA. Infect Immun 2004; 72:7096–7106.PubMedCrossRefGoogle Scholar
  36. 36.
    Stokes MGM, Titball RW, Neeson BN et al. Oral administration of a Salmonella enterica-based vaccine expressing Bacillus anthracis protective antigen confers protection against aerosolized B-anthracis. Infect Immun 2007; 75:1827–1834.PubMedCrossRefGoogle Scholar
  37. 37.
    Baillie LWJ, Rodriguez AL, Moore S et al. Towards a human oral vaccine for anthrax: The utility of a Salmonella Typhi Ty21a-based prime-boost immunization strategy. Vaccine 2008; 26:6083–6091.PubMedCrossRefGoogle Scholar
  38. 38.
    Chinchilla M, Pasetti MF, Medina-Moreno S et al. Enhanced immunity to Plasmodium falciparum circumsporozoite protein (PfCSP) by using Salmonella enterica serovar Typhi expressing PfCSP and a PfCSP-encoding DNA vaccine in a heterologous prime-boost strategy. Infect Immun 2007; 75:3769–3779.PubMedCrossRefGoogle Scholar
  39. 39.
    Kim JY, Doody AM, Chen DJ et al. Engineered bacterial outer membrane vesicles with enhanced functionality. J Mol Biol 2008; 380:51–66.PubMedCrossRefGoogle Scholar
  40. 40.
    Ryan RM, Green J, Hunt S et al. Bacterial delivery of a novel cytolysin to hypoxic areas of solid tumors. Gene Ther 2009; 16:329–339.PubMedCrossRefGoogle Scholar
  41. 41.
    Madegowda M, Eswaramoorthy S, Burley SK et al. X-ray crystal structure of the B component of Hemolysin BL from Bacillus cereus. Proteins Struct Funct Bioinformat 2008; 71:534–540.CrossRefGoogle Scholar
  42. 42.
    Fagerlund A, Lindback T, Storset AK et al. Bacillus cereus Nhe is a pore-forming toxin with structural and functional properties similar to the ClyA (HIyE, SheA) family of haemolysins, able to induce osmotic lysis in epithelia. Microbiology 2008; 154:693–704.PubMedCrossRefGoogle Scholar
  43. 43.
    Arnesen LPS, Fagerlund A, Granum PE. From soil to gut: Bacillus cereus and its food poisoning toxins. FEMS Microbiology Reviews 2008; 32:579–606.CrossRefGoogle Scholar
  44. 44.
    Presnell SR, Cohen FE. Topological distribution of 4 alpha helix bundles. Proc Natl Acad Sci USA 1989; 86:6592–6596.PubMedCrossRefGoogle Scholar
  45. 45.
    Harris NL, Presnell SR, Cohen FE. 4 helix bundle diversity in globular proteins. J Mol Biol 1994; 236:1356–1368.PubMedCrossRefGoogle Scholar
  46. 46.
    Ansong C, Yoon H, Norbeck AD et al. Proteomics analysis of the causative agent of typhoid fever. J Proteome Res 2008; 7:546–557.PubMedCrossRefGoogle Scholar
  47. 47.
    Fuentes JA, Villagra N, Castillo-Ruiz M et al. The Salmonella typhi hlyE gene plays a role in invasion of cultured epithelial cells and its functional transfer to S. typhimurium promotes deep organ infection in mice. Res Microbiol 2008; 159:279–287.PubMedCrossRefGoogle Scholar
  48. 48.
    DeLano WL, Lam JW. PyMOL: A communications tool for computational models. Abstracts of Papers of the American Chemical Society 2005; 230:254-COMP.Google Scholar

Copyright information

© Landes Bioscience and Springer Science+Business Media 2010

Authors and Affiliations

  • Stuart Hunt
    • 1
  • Jeffrey Green
    • 1
  • Peter J. Artymiuk
    • 1
  1. 1.The Krebs Institute, Department of Molecular Biology and BiotechnologyUniversity of SheffieldSheffieldUK

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