PMID:15199181

Citation	Sheahan, KL, Cordero, CL and Satchell, KJ (2004) Identification of a domain within the multifunctional Vibrio cholerae RTX toxin that covalently cross-links actin. Proc. Natl. Acad. Sci. U.S.A. 101:9798-803
Abstract	The Gram-negative pathogen Vibrio cholerae causes diarrheal disease through the export of enterotoxins. The V. cholerae RTX toxin was previously identified and characterized by its ability to round human laryngeal epithelial (HEp-2) cells. Further investigation determined that cell rounding is caused by the depolymerization of actin stress fibers, through the unique mechanism of covalent actin cross-linking. In this study, we identify a domain within the full-length RTX toxin that is capable of mediating the cross-linking reaction when transiently expressed within eukaryotic cells. A structure/function analysis of the actin cross-linking domain (ACD) reveals that a 412-aa, or a 47.8-kDa, region is essential for cross-linking activity. When this domain is deleted from the full-length toxin gene, actin cross-linking, but not cell rounding, is eliminated, indicating that this toxin carries multiple dissociable activities. The ACD shares 59% amino acid identity with a hypothetical protein from V. cholerae, VC1416, and transient expression of the C-terminal domain of VC1416 also results in actin cross-linking in eukaryotic cells. The presence of this second ACD linked to an Rhs-like element suggests that V. cholerae acquired the domain by horizontal gene transfer and the ACD was inserted into the RTX toxin by gene duplication through the evolution of V. cholerae.
Links	PubMed PMC470754 Online version:10.1073/pnas.0401104101
Keywords	Actins/chemistry; Actins/metabolism; Acyltransferases/chemistry; Acyltransferases/genetics; Acyltransferases/metabolism; Animals; Bacterial Proteins/chemistry; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Bacterial Toxins/chemistry; Bacterial Toxins/genetics; Bacterial Toxins/metabolism; Cell Line; Cell Size; Chromosomes, Bacterial/genetics; Epithelial Cells; Gene Duplication; Humans; Larynx; Molecular Weight; Multienzyme Complexes/chemistry; Multienzyme Complexes/genetics; Multienzyme Complexes/metabolism; Protein Structure, Tertiary; Sequence Deletion/genetics; Stress Fibers/chemistry; Stress Fibers/metabolism; Structure-Activity Relationship; Vibrio/metabolism; Vibrio cholerae/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
VIBCH:Q9KS12	involved_in	GO:0018262: isopeptide cross-linking	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
VIBCH:Q9KS12	involved_in	GO:0030042: actin filament depolymerization	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete

References

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