Members of this family are proteins/peptides, synthesized by one cell and secreted for insertion into the membrane of another cell where they form transmembrane pores. Pore-forming toxins (PFTs) are the most common bacterial cytotoxic proteins and are required for virulence in a large number of important pathogens.
Over 100 subgroups belong to the "Pore-forming Toxins" family, including amongst others:
- The α-Hemolysin Channel-forming Toxin (αHL) Family
- The Aerolysin Channel-forming Toxin (Aerolysin) Family
- The Botulinum and Tetanus Toxin (BTT) Family
- The Pertussis Toxin (PTX) Family
- The Crystal Protein (Cry) Family
Aerolysin Background Information
The aerolysins are a closely related group of channel-forming toxins secreted by members of the family Aeromonas, important human and animal pathogens. They are activated by host and bacterial proteases which remove a C-terminal fragment of about 40 amino acyl residues. The activated monomeric toxin then binds to a receptor glycosyl phosphatidylinositol (GPI)-anchored protein on the surface of the target cell.
UniProt: P09167 (Aeromonas hydrophila)
Homodimer in solution; homoheptamer in the host membrane.
The mature toxin binds to eukaryotic cells and aggregates to form holes (approximately 3 nm in diameter) leading to the destruction of the membrane permeability barrier and osmotic lysis. Proteolytic cleavage and subsequent release of the propeptide trigger a major conformation change, leading to the formation of a heptameric pre-pore that then inserts into the host membrane.
Bilayer Recordings on the Orbit Product family
Reviews and Links
- Podobnik et al.: Molecular mechanism of pore formation by aerolysin-like proteins (2017) Philos Trans R Soc Lond B Biol Sci. doi: 10.1098/rstb.2016.0209
Transporter classification database: