Protein interactome mapping of Porphyromonas gingivalis provides insights into the formation of the PorQ‐Z complex of the type IX secretion system

Porphyromonas gingivalis is an anaerobic Gram‐negative human oral pathogen highly associated with the more severe forms of periodontal disease. Porphyromonas gingivalis utilises the type IX secretion system (T9SS) to transport ∼30 cargo proteins, including multiple virulence factors, to the cell surface. The T9SS is a multiprotein system consisting of at least 20 proteins, and this study characterised the protein interactome of these components. Like the T9SS, almost all biological processes are mediated through protein-protein interactions (PPIs). Therefore, mapping PPIs is important to understand the biological functions of many proteins in P. gingivalis. The study provides native migration profiles of over 1000 P. gingivalis proteins. Using this dataset and further analysis of T9SS P. gingivalis mutants, the study discovers new mechanistic insights into forming the PorQ‐Z complex of the T9SS.