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Updated: May 6, 2026

Quantifying Yersinia pseudotuberculosis Type III Secretion System Activity Following Iron Starvation and Anaerobic Growth
Published on: May 31, 2024
The ESX-3 secretion system is necessary for iron and zinc homeostasis in Mycobacterium tuberculosis
Agnese Serafini1, Davide Pisu, Giorgio Palù
1Department of Molecular Medicine, University of Padova, Padova, Italy.
Abstract:
ESX-3 is one of the five type VII secretion systems encoded by the Mycobacterium tuberculosis genome. We recently showed the essentiality of ESX-3 for M. tuberculosis viability and proposed its involvement in iron and zinc metabolism. In this study we confirmed the role of ESX-3 in iron uptake and its involvement in the adaptation to low zinc environment in M. tuberculosis. Moreover, we unveiled functional differences between the ESX-3 roles in M. tuberculosis and M. smegmatis showing that in the latter ESX-3 is only involved in the adaptation to iron and not to zinc restriction. Finally, we also showed that in M. tuberculosis this secretion system is essential for iron and zinc homeostasis not only in conditions in which the concentrations of these metals are limiting but also in metal sufficient conditions.
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