Identification of a domain within the multifunctional Vibrio cholerae RTX toxin that covalently cross-links actin

Kerri Lynn Sheahan, Christina L. Cordero, Karla J.Fullner Satchell*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

110 Scopus citations

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.

Original languageEnglish (US)
Pages (from-to)9798-9803
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume101
Issue number26
DOIs
StatePublished - Jun 29 2004

Keywords

  • Covalent actin cross-linking
  • VgrG
  • Vibrio vulnificus

ASJC Scopus subject areas

  • General

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