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Bacterial secretion systems

Tuesday 28 February 2012, by Christian CAMBILLAU

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To survive, bacteria have to exchange molecules with their environment. As they have evolved, bacteria have developed extremely smart systems to import and export molecules through their membranes. Pathogenic bacteria use these systems to inject toxic molecules in their cell targets. Such systems are therefore associated to virulence making of them interesting targets in the fight against bacterial infections.

collaborations: Dr. Romé Voulhoux, LISM, Marseille, France; Dr. Éric Cascales, LISM, Marseille, France.


Type 2 secretion system

To better understand their function, we study the molecular architecture of two types of bacterial secretion systems, namely type II (T2SS) and type VI (T6SS). We undertook first the systematic study of the interaction network of five pseudopilins from Pseudomonas aeruginosa T2SS by surface plasmon resonance (PMID:19828448) [1]. This study confirmed the existence within this system of a XcpV(I)-W(J)-X(K) heterotrimer, previously observed by X-ray crystallography. But the study has also suggested the possibility of a tetrameric complex that would add XcpU(H) to the end of the pseudopilus.

In a second step, we are studying the structures of several components of T2SS and T6SS. We expect that these structures will give us clues to design molecules able to block the assembly of the secretion systems, thus allowing the selective targeting of specific bacterial infections.