Cellular and structural studies of type-IX dependent secretion in Porphyromonas gingivalis.


Many bacteria form outer-membrane vesicles (OMVs) via blebbing of their outer-membrane (OM). These function in biofilm-formation, host-invasion, nutrient-acquisition and subversion of host responses. They can diffuse long distances and fuse with other bacteria and hosts, releasing their contents. Porphyromonas gingivalis is a Gram-negative bacterium of the oral cavity that causes chronic periodontitis. It utilizes a type-IX secretion system (T9SS/PorSS) to export virulence factors across its OM. These are covalently attached to the cell surface but also enriched in OMVs. Using molecular microbiology and structural biology techniques this project aims to understanding the links between type IX-dependent secretion and OMV biogenesis.


Nakayama, K. (2015) Porphyromonas gingivalis and related bacteria: from colonial pigmentation to the type IX secretion system and gliding motility. J. Periodint. Res. 50: 1-8.


Haurat, M.F., Aduse-Opoku, J., Rangarajan, M., Dorobantu, L., Gray, M.R., Curtis, M.A. & Feldman, M.F. (2011) Selective Sorting of Cargo Proteins into Bacterial Membrane Vesicles. J. Biol. Chem. 286: 1269–1276


Gorasia, D.G., Veith, P.D., Chen, D., Seers, C.A., Mitchell, H.A., Chen, Y-Y., Glew, M.D., Dashper, S.G. & Reynolds, E.c. (2015) Porphyromonas gingivalis Type IX Secretion Substrates Are Cleaved and Modified by a Sortase-Like Mechanism. PLoS Path. 11, e1005152.


Pakharukova, N., Garnett, J.A., Tuittila,M., Paavilainen, S., Diallo, M., Xu, Y., Matthews, S.J. & Zaviolov, A.V. (2015) Structural Insight into Archaic and Alternative Chaperone-Usher Pathways Reveals a Novel Mechanism of Pilus Biogenesis. PLoS Pathog. 11, e1005269


Garnett, J.A., Martínez-Santos, V.I., Saldaña, Pape, T., Hawthorne, W., Chan, J., Simpson, P., Cota, E., Puente, J.L., Girón, J.A. and Matthews, S. (2012). Structural insights into the biogenesis and biofilm formation by the E. coli common pilus. Proc. Nat. Acad. of Sci. U.S.A. 109, 3950-3955.

Biological Areas:

Structural Biology


Plants, microbes, food and sustainability