Vibrio choleraeMARTX toxin heterologous translocation of beta-lactamase and roles of individual effector domains on cytoskeleton dynamics

Jazel S. Dolores, Shivani Agarwal, Martina Egerer, Karla J.F. Satchell*

*Corresponding author for this work

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

Summary: The Vibrio choleraeMARTXVc toxin delivers three effector domains to eukaryotic cells. To study toxin delivery and function of individual domains, the rtxA gene was modified to encode toxin with an in-frame beta-lactamase (Bla) fusion. The hybrid RtxA::Bla toxin was Type I secreted from bacteria; and then Bla was translocated into eukaryotic cells and delivered by autoprocessing, demonstrating that the MARTXVc toxin is capable of heterologous protein transfer. Strains that produce hybrid RtxA::Bla toxins that carry one effector domain in addition to Bla were found to more efficiently translocate Bla. In cell biological assays, the actin cross-linking domain (ACD) and Rho-inactivation domain (RID) are found to cross-link actin and inactivate RhoA, respectively, when other effector domains are absent, with toxin autoprocessing required for high efficiency. The previously unstudied alpha-beta hydrolase domain (ABH) is shown here to activate CDC42, although the effect is ameliorated when RID is also present. Despite all effector domains acting on cytoskeleton assembly, the ACD was sufficient to rapidly inhibit macrophage phagocytosis. Both the ACD and RID independently disrupted polarized epithelial tight junction integrity. The sufficiency of ACD but strong selection for retention of RID and ABH suggests these two domains may primarily function by modulating cell signaling.

Original languageEnglish (US)
Pages (from-to)590-604
Number of pages15
JournalMolecular Microbiology
Volume95
Issue number4
DOIs
StatePublished - Feb 1 2015

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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