title: Host cell cytotoxicity and cytoskeleton disruption by CerADPr, an ADP-ribosyltransferase of Bacillus cereus G9241.
abstract: Bacillus cereus G9241 was isolated from a welder suffering from an anthrax-like inhalation illness. B. cereus G9241 encodes two megaplasmids, pBCXO1 and pBC210, which are analogous to the toxin- and capsule-encoding virulence plasmids of Bacillus anthracis. Protein modeling predicted that the pBC210 LF homologue contained an ADP-ribosyltransferase (ADPr) domain. This putative bacterial ADP-ribosyltransferase domain was denoted CerADPr. Iterative modeling showed that CerADPr possessed several conserved ADP-ribosyltransferase features, including an α-3 helix, an ADP-ribosyltransferase turn-turn loop, and a "Gln-XXX-Glu" motif. CerADPr ADP-ribosylated an ~120 kDa protein in HeLa cell lysates and intact cells. EGFP-CerADPr rounded HeLa cells, elicited cytoskeletal changes, and yielded a cytotoxic phenotype, indicating that CerADPr disrupts cytoskeletal signaling. CerADPr(E431D) did not possess ADP-ribosyltransferase or NAD glycohydrolase activities and did not elicit a phenotype in HeLa cells, implicating Glu431 as a catalytic residue. These experiments identify CerADPr as a cytotoxic ADP-ribosyltransferase that disrupts the host cytoskeleton.
authors.affiliation: Microbiology, Immunology, and Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
authors.forename: Nathan C
authors.initials: NC
authors.lastname: Simon
authors.forename: James M
authors.initials: JM
authors.lastname: Vergis
authors.forename: Avesta V
authors.initials: AV
authors.lastname: Ebrahimi
authors.forename: Christy L
authors.initials: CL
authors.lastname: Ventura
authors.forename: Alison D
authors.initials: AD
authors.lastname: O'Brien
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Barbieri
mesh_terms: D036002:ADP Ribose Transferases / Q000737:chemistry / Q000378:metabolism*; D000595:Amino Acid Sequence; D000881:Anthrax / Q000382:microbiology; D001409:Bacillus cereus / Q000201:enzymology* / Q000302:isolation & purification / Q000502:physiology*; D020134:Catalytic Domain; D003599:Cytoskeleton / Q000382:microbiology*; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary
chemical_list: D036002:ADP Ribose Transferases