Drilling holes into cell membranes: the wonderful world of the pore-forming proteins
Pore-forming toxins (PFT) constitute the largest and best characterized class of protein toxins, accounting for more than 30% of all known bacterial protein toxins. They are potent virulence factors evolved during ancient competition among organisms for defense and/or attack purposes. Interestingly, similar structures and modes of action are also adopted by components of the immune system, like perforin and complement.
PFT are normally able to drill poorly selective nanometer-sized holes into the target cell membranes, causing cell death through osmotic imbalance.
Regarding the pore structure, two conformations have been described: a purely proteinic channel or a protein-lipid mixed arrangement. This second case is characterized by the co-presence of lipidic and protein elements in the pore walls. Lipid heads could either intercalate between protein monomers or constitute the chord of arc shaped pores. In both cases the lipid lamellar structure is destroyed and lipids should bend, assuming a toroidal shape.
Here I will discuss how the Planar Lipid Membrane measurements combined with Atomic Force Microscopy topological analyses could help to understand how transmembrane pores are formed by cholesterol-dependent cytolysins (CDCs), a toxin family from pathogenic bacteria, and actinoporins, cytolysins from sea anemones. I will present experimental evidences supporting the ability of these two unrelated protein families to punch proteolipidic nanopores into lipid membranes.
About the speaker:
Mauro Dalla Serra
National Research Council of Italy - Institute of Biophysics & Bruno Kessler Foundation
via Sommarive 18, 38123 Trento, Italy
e.mail: mauro.dallaserra [at] cnr.it
For further information:
Prof. Dr. Roland Benz
Professor of Biotechnology
Life Sciences and Chemistry - Focus area Health
Building Research II, Room 89 / Campus Ring 6 / 28759 Bremen / Germany
Email: r.benz [at] jacobs-university.de
Tel: +49 421 200-3151 / Fax: +49 421 200-3249
Link to Homepage: r.benz [at] jacobs-university.de Tel: +49 421 200-3151 / Fax: +49 421 200-3249 Link to Homepage: https://www.jacobs-university.de/ses/rbenz">https://www.jacobs-university.de/ses/rbenz