Autotransporters as scaffolds for novel bacterial adhesins: surface properties of Escherichia coli cells displaying Jun/Fos dimerization domains.

Hybrid proteins containing the beta-autotransporter domain of the immunoglobulin A (IgA) protease of Neisseria gonorrhoea (IgA beta) and the partner leucine zippers of the eukaryotic transcriptional factors Fos and Jun were expressed in Escherichia coli. Such fusion proteins targeted the leucine zipper modules to the cell surface. Cells displaying the Jun beta sequence flocculated shortly after induction of the hybrid protein. E. coli cells expressing separately Fos beta and Junbeta chimeras formed stable bacterial consortia. These associations were physically held by tight intercell ties caused by the protein-protein interactions of matching dimerization domains. The role of autotransporters in the emergence of new adhesins is discussed.