The Photorhabdus asymbiotica virulence cassettes deliver protein effectors directly into target eukaryotic cells

• Main Authors: Isabella Vlisidou, Alexia Hapeshi, Joseph RJ Healey, Katie Smart, Guowei Yang, Nicholas R Waterfield
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2019-09-01
• Series: eLife
• Subjects: Photorhabdus; toxins; secretion
• Online Access: https://elifesciences.org/articles/46259

Photorhabdus is a highly effective insect pathogen and symbiont of insecticidal nematodes. To exert its potent insecticidal effects, it elaborates a myriad of toxins and small molecule effectors. Among these, the Photorhabdus Virulence Cassettes (PVCs) represent an elegant self-contained delivery mechanism for diverse protein toxins. Importantly, these self-contained nanosyringes overcome host cell membrane barriers, and act independently, at a distance from the bacteria itself. In this study, we demonstrate that Pnf, a PVC needle complex associated toxin, is a Rho-GTPase, which acts via deamidation and transglutamination to disrupt the cytoskeleton. TEM and Western blots have shown a physical association between Pnf and its cognate PVC delivery mechanism. We demonstrate that for Pnf to exert its effect, translocation across the cell membrane is absolutely essential.