title: Photorhabdus luminescens toxins ADP-ribosylate actin and RhoA to force actin clustering.
abstract: The bacterium Photorhabdus luminescens is mutualistically associated with entomopathogenetic nematodes. These nematodes invade insect larvae and release the bacteria from their intestine, which kills the insects through the action of toxin complexes. We elucidated the mode of action of two of these insecticidal toxins from P. luminescens. We identified the biologically active components TccC3 and TccC5 as adenosine diphosphate (ADP)-ribosyltransferases, which modify unusual amino acids. TccC3 ADP-ribosylated threonine-148 of actin, resulting in actin polymerization. TccC5 ADP-ribosylated Rho guanosine triphosphatase proteins at glutamine-61 and glutamine-63, inducing their activation. The concerted action of both toxins inhibited phagocytosis of target insect cells and induced extensive intracellular polymerization and clustering of actin. Several human pathogenic bacteria produce related toxins.
authors.affiliation: Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Albert-Ludwigs-Universität Freiburg, 79104 Freiburg, Germany.
authors.forename: Alexander E
authors.initials: AE
authors.lastname: Lang
authors.forename: Gudula
authors.initials: G
authors.lastname: Schmidt
authors.forename: Andreas
authors.initials: A
authors.lastname: Schlosser
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Hey
authors.forename: Ignacio M
authors.initials: IM
authors.lastname: Larrinua
authors.forename: Joel J
authors.initials: JJ
authors.lastname: Sheets
authors.forename: Hans G
authors.initials: HG
authors.lastname: Mannherz
authors.forename: Klaus
authors.initials: K
authors.lastname: Aktories
mesh_terms: D036002:ADP Ribose Transferases / Q000737:chemistry / Q000378:metabolism*; D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000818:Animals; D001427:Bacterial Toxins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D002460:Cell Line; D005973:Glutamine / Q000378:metabolism; D006367:HeLa Cells; D006434:Hemocytes / Q000276:immunology; D006801:Humans; D009036:Moths; D010587:Phagocytosis / Q000187:drug effects; D020637:Photorhabdus; D015398:Signal Transduction; D022502:Stress Fibers / Q000378:metabolism; D013912:Threonine / Q000378:metabolism; D013947:Thymosin / Q000378:metabolism / Q000494:pharmacology; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*; D000099201:Thymosin beta(4)
chemical_list: D036002:ADP Ribose Transferases; D000199:Actins; D000246:Adenosine Diphosphate Ribose; D001427:Bacterial Toxins; D005973:Glutamine; D013912:Threonine; D013947:Thymosin; D020742:rhoA GTP-Binding Protein; D000099201:Thymosin beta(4); C118454:toxin A, Photorhabdus; C118455:toxin B, Photorhabdus