Tagging the type VI secretion system

Olivera Francetic (1)

1 Biochimie des Interactions Macromoléculaires / Biochemistry of Macromolecular Interactions

Bacteria use multiple mechanisms to secrete proteins across their envelope and gain access to resources in their niche. The type VI secretion system (T6SS) specializes in injecting toxic protein effectors by direct contact, killing the target eukaryotic or bacterial cells1. T6SSs share common origins with contractile-tail bacteriophages, which attach to the cell surface and inject their DNA by puncturing the membrane with their tail spike. In T6SSs, the tail-like structures are built inside the cytoplasm and inversely oriented, with their spike pointing outwards (Fig. 1). The T6SS tail is composed of an external layer — a contractile sheath — and a hollow inner tube that stores small protein effectors prior to secretion. Similar to an armed crossbow, the assembled T6SS remains inactive and ready to fire until it somehow senses a prey cell within firing range. This activates sheath contraction and exposes the spike, which penetrates the prey cell envelope and delivers its deadly cargo.

Domaines: Sciences du Vivant [q-bio]; Microbiologie et Parasitologie

Olivera Francetic. Tagging the type VI secretion system. Nature Microbiology, 2018, 3 (11), pp.1190-1191. ⟨10.1038/s41564-018-0277-5⟩. ⟨pasteur-02559634⟩