A journey with type IX secretion system effectors: selection, transport, processing and activities

Maëlle Paillat (1) , Ignacio Lunar Silva (1) , Eric Cascales (1) , Thierry Doan (1)

1 LISM - Laboratoire d'ingénierie des systèmes macromoléculaires

The type IX secretion system (T9SS) is a multiprotein machine distributed in Bacteroidota and responsible for the secretion of various proteins across the outer membrane. Secreted effectors can be either delivered into the medium or anchored to the cell surface. The T9SS is composed of a transenvelope complex consisting of proton-motive force-dependent motors connected to a membrane-associated ring and outer membrane translocons, and a cell-surface anchoring complex that processes effectors once translocated. The T9SS is involved in pathogenesis, metal acquisition, carbohydrate degradation, S-layer biogenesis and gliding motility. The broad spectrum of functions is linked to a highly versatile repertoire of effectors including metallophores, enzymes, toxins and adhesins, that all possess specific signatures to be recruited and transported by the apparatus. This review summarizes the current knowledge on T9SS substrate secretion signals, transport, processing and activities.

Mots clés: anionic lipopolysaccharide CTD; C-terminal domain OM; outer membrane PMF; proton motive force TMH; transmembrane helix T9SS; type IX secretion system; protein transport; secretion signal; effectors; toxins; type IX secretion; gliding motility. Abbreviations: A-LPS; anionic lipopolysaccharide; CTD; C-terminal domain; OM; outer membrane; PMF; proton motive force; TMH; transmembrane helix; T9SS

Domaines: Sciences du Vivant [q-bio]

Maëlle Paillat, Ignacio Lunar Silva, Eric Cascales, Thierry Doan. A journey with type IX secretion system effectors: selection, transport, processing and activities. Microbiology, 2023, 169 (4), ⟨10.1099/mic.0.001320⟩. ⟨hal-04234754⟩