Significance Entry of bacteria into host cells critically depends on their proper engulfment by the plasma membrane. So far, actin polymerization has been described as a major driving force in this process. However, our study reveals that the interaction of the bacterial surface lectin LecA with the host cell glycosphingolipid Gb3 is fully sufficient to promote engulfment of Pseudomonas aeruginosa , whereas actin polymerization is dispensable. Hence, the formation of a “lipid zipper” represents a previously unidentified mechanism of bacterial uptake and demonstrates that bacterial pathogens have evolved lipid-based invasion strategies that may function in addition to protein receptor-based ones. Furthermore, by identifying the LecA/Gb3 interaction as the major invasion-promoting factor, our study provides new targets for drugs that may prevent bacterial invasion and dissemination.

Background: Burkholderia ambifaria is a plant-associated bacteria responsible for opportunistic infections in human. Results:The ␤-propeller BambL lectin is specific for fucosylated oligosaccharides with higher affinity for biological samples from secretor individuals. Conclusion:The recombinant BambL lectin binds to both plant and human oligosaccharides. Significance: The diversity of fucosylated epitopes may play a role in host recognition in mammals and plants.