biostudies-literatureMassey JHNIAID NIH HHSNational Institutes of HealthNational Science Foundation185-198https://www.ebi.ac.uk/biostudies/studies/S-EPMC8742837biostudies-literatureUnknown30(2)Bacterial endosymbionts induce dramatic phenotypes in their arthropod hosts, including cytoplasmic incompatibility, feminization, parthenogenesis, male killing, parasitoid defense, and pathogen blocking. The molecular mechanisms underlying these effects remain largely unknown but recent evidence suggests that protein toxins secreted by the endosymbionts play a role. Here, we describe the diversity and function of endosymbiont proteins with homology to known bacterial toxins. We focus on maternally transmitted endosymbionts belonging to the Wolbachia, Rickettsia, Arsenophonus, Hamiltonella, Spiroplasma, and Cardinium genera because of their ability to induce the above phenotypes. We identify at least 16 distinct toxin families with diverse enzymatic activities, including AMPylases, nucleases, proteases, and glycosyltransferases. Notably, several annotated toxins contain domains with homology to eukaryotic proteins, suggesting that arthropod endosymbionts mimic host biochemistry to manipulate host physiology, similar to bacterial pathogens.Trends in microbiologyDiversity and function of arthropod endosymbiont toxins.PMC8742837BII 2022049R01AI144430R01 AI144430Newton ILGMassey JHfalseDiversity and function of arthropod endosymbiont toxins.Bacterial endosymbionts induce dramatic phenotypes in their arthropod hosts, including cytoplasmic incompatibility, feminization, parthenogenesis, male killing, parasitoid defense, and pathogen blocking. The molecular mechanisms underlying these effects remain largely unknown but recent evidence suggests that protein toxins secreted by the endosymbionts play a role. Here, we describe the diversity and function of endosymbiont proteins with homology to known bacterial toxins. We focus on maternally transmitted endosymbionts belonging to the Wolbachia, Rickettsia, Arsenophonus, Hamiltonella, Spiroplasma, and Cardinium genera because of their ability to induce the above phenotypes. We identify at least 16 distinct toxin families with diverse enzymatic activities, including AMPylases, nucleases, proteases, and glycosyltransferases. Notably, several annotated toxins contain domains with homology to eukaryotic proteins, suggesting that arthropod endosymbionts mimic host biochemistry to manipulate host physiology, similar to bacterial pathogens.2022-01-01T00:00:00Z2022 Feb2024-11-20T12:13:40.319Z2024-11-20T12:13:40.319ZS-EPMC87428373425345310.1016/j.tim.2021.06.008