# Molecular mechanism of V. vulnificus MARTX toxin in pathogenesis and food safety

> **NIH NIH R01** · NORTHWESTERN UNIVERSITY · 2020 · $410,572

## Abstract

Project Summary
Vibrio vulnificus is a natural inhabitant of coastal waters, including the US Gulf. The bacterium causes severe
life threatening infections after consumption of contaminated seafood (especially raw oysters) and from
wounds contaminated by seawater. Among food-borne pathogens, V. vulnificus is most notable for its high
rates of hospitalization and death and its negative economic impact. Indeed, V. vulnificus accounts for 72% of
deaths from Vibrio illnesses despite causing only 13% of infections. Although infections are rare, the number of
serious infections has been increasing globaly due to climate change that has caused a rise in the number of
days amenable to growth of V. vulnificus in coastal waters and the geographical area amenable to the
pathogen. Attempts by various agency to warn and protect citezens by implementation of new policies or
issuing warnings have met with resistance for it effect on the shellfish harvesting industry and the tourist
economy. Thus, the study of V. vulnificus pathogenesis has become both a food safety and public policy
priority. A significant virulence factor of V. vulnificus is the large Multifunctional-Autoprocessing RTX toxin
(MARTXVv). This toxin is comprised of long repeat regions that are associated with cellular necrosis, but this
activity is not sufficient for virulence. Rather, virulence is associated with “effector domains” that are
translocated across host plasma membrane by repeat regions, and then released to the cell cytosol by inositol
hexakisphophate induced autoprocessing. Bioinformatics studies reveal that different clinical isolates of V.
vulnificus express distinct forms of the toxin, with five different variants assembled from eight different MARTX
effector domains. To date, the mechanism of action of five of these domains has been determined. In this
project, we will investigate the mechanism of action of the remaining effector domains found in clinical isolates.
Further, we will study the relative toxicity of different variants of MARTXVv toxin in pathogenesis by the food-
borne route of infection.

## Key facts

- **NIH application ID:** 9812824
- **Project number:** 5R01AI092825-09
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Karla J F Satchell
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $410,572
- **Award type:** 5
- **Project period:** 2011-07-01 → 2021-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9812824

## Citation

> US National Institutes of Health, RePORTER application 9812824, Molecular mechanism of V. vulnificus MARTX toxin in pathogenesis and food safety (5R01AI092825-09). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9812824. Licensed CC0.

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