Porin self-association enables cell-to-cell contact in
El-Khatib, M., Nasrallah, C., Lopes, J., Tran, Q.T., Tetreau, G., Basbous, H., Fenel, D., Gallet, B., Lethier, M., Bolla, J.M., Pages, J.M., Vivaudou, M., Weik, M., Winterhalter, M., Colletier, J.P.(2018) Proc Natl Acad Sci U S A 115: E2220-E2228
- PubMed: 29476011 
- DOI: https://doi.org/10.1073/pnas.1714582115
- Primary Citation of Related Structures:  
4D64, 4D65, 5N9H, 5N9I, 5NXN, 5NXR, 5NXU - PubMed Abstract: 
The gram-negative pathogen Providencia stuartii forms floating communities within which adjacent cells are in apparent contact, before depositing as canonical surface-attached biofilms. Because porins are the most abundant proteins in the outer membrane of gram-negative bacteria, we hypothesized that they could be involved in cell-to-cell contact and undertook a structure-function relationship study on the two porins of P. stuartii , Omp-Pst1 and Omp-Pst2. Our crystal structures reveal that these porins can self-associate through their extracellular loops, forming dimers of trimers (DOTs) that could enable cell-to-cell contact within floating communities. Support for this hypothesis was obtained by studying the porin-dependent aggregation of liposomes and model cells. The observation that facing channels are open in the two porin structures suggests that DOTs could not only promote cell-to-cell contact but also contribute to intercellular communication.
Organizational Affiliation: 
Institut de Biologie Structurale (IBS), University of Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 38000 Grenoble, France.