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Environmental Salinity Determines the Specificity and Need for Tat-Dependent Secretion of the YwbN Protein in Bacillus subtilis

Lookup NU author(s): Dr Ulrike Mader, Dr Georg Homuth, Professor Colin Harwood



Twin-arginine protein translocation (Tat) pathways are required for transport of folded proteins across bacterial, archaeal and chloroplast membranes. Recent studies indicate that Tat has evolved into a mainstream pathway for protein secretion in certain halophilic archaea, which thrive in highly saline environments. Here, we investigated the effects of environmental salinity on Tat-dependent protein secretion by the Gram-positive soil bacterium Bacillus subtilis, which encounters widely differing salt concentrations in its natural habitats. The results show that environmental salinity determines the specificity and need for Tat-dependent secretion of the Dyp-type peroxidase YwbN in B. subtilis. Under high salinity growth conditions, at least three Tat translocase subunits, namely TatAd, TatAy and TatCy, are involved in the secretion of YwbN. Yet, a significant level of Tat-independent YwbN secretion is also observed under these conditions. When B. subtilis is grown in medium with 1% NaCl or without NaCl, the secretion of YwbN depends strictly on the previously described "minimal Tat translocase" consisting of the TatAy and TatCy subunits. Notably, in medium without NaCl, both tatAyCy and ywbN mutants display significantly reduced exponential growth rates and severe cell lysis. This is due to a critical role of secreted YwbN in the acquisition of iron under these conditions. Taken together, our findings show that environmental conditions, such as salinity, can determine the specificity and need for the secretion of a bacterial Tat substrate.

Publication metadata

Author(s): van der Ploeg R, Mader U, Homuth G, Schaffer M, Denham EL, Monteferrante CG, Miethke M, Marahiel MA, Harwood CR, Winter T, Hecker M, Antelmann H, van Dijl JM

Publication type: Article

Publication status: Published

Journal: PLoS ONE

Year: 2011

Volume: 6

Issue: 3

Print publication date: 30/03/2011

Date deposited: 12/07/2011

ISSN (print):

ISSN (electronic): 1932-6203

Publisher: Public Library of Science


DOI: 10.1371/journal.pone.0018140


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Funder referenceFunder name
Deutsche Forschungsgemeinschaft
European Science Foundation
Fonds der Chemischen Industrie
03ZIK012Bundesministerium fur Bildung und Forschung
04-EScope 01-011Research Council for Earth and Life Sciences of the Netherlands Organization for Scientific Research
BACELL SysMO1transnational Systems Biology of Microorganisms (SysMO) initiative
BACELL SysMO2transnational Systems Biology of Microorganisms (SysMO) initiative
LSHG-CT-2004-005257Commission of the European Union (CEU)
LSHG-CT-2004-503468Commission of the European Union (CEU)
LSHG-CT-2006-037469Commission of the European Union (CEU)
LSHM-CT-2006-019064Commission of the European Union (CEU)
PITN-GA-2008-215524Commission of the European Union (CEU)