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J Mol Biol. 2015 Apr 24;427(8):1715-27. doi: 10.1016/j.jmb.2015.01.025. Epub 2015 Feb 10.

Translation elongation factor EF-Tu modulates filament formation of actin-like MreB protein in vitro.

Author information

1
Microbiology, Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104 Freiburg, Germany. Electronic address: joel.defeusoufo@biologie.uni-freiburg.de.
2
LOEWE Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Philipps Universität, 35037 Marburg, Germany.
3
Abteilung für Anatomie und Molekulare Embryologie, Ruhr-Universität, 44801 Bochum, Germany.
4
LOEWE Center for Synthetic Microbiology (SYNMIKRO) and Department of Chemistry, Philipps Universität, 35037 Marburg, Germany. Electronic address: peter.graumann@synmikro.uni-marburg.de.

Abstract

EF-Tu has been shown to interact with actin-like protein MreB and to affect its localization in Escherichia coli and in Bacillus subtilis cells. We have purified YFP-MreB in an active form, which forms filaments on glass slides in vitro and was active in dynamic light-scattering assays, polymerizing in milliseconds after addition of magnesium. Purified EF-Tu enhanced the amount of MreB filaments, as seen by sedimentation assays, the speed of filament formation and the length of MreB filaments in vitro. EF-Tu had the strongest impact on MreB filaments in a 1:1 ratio, and EF-Tu co-sedimented with MreB filaments, revealing a stoichiometric interaction between both proteins. This was supported by cross-linking assays where 1:1 species were well detectable. When expressed in E. coli cells, B. subtilis MreB formed filaments and induced the formation of co-localizing B. subtilis EF-Tu structures, indicating that MreB can direct the positioning of EF-Tu structures in a heterologous cell system. Fluorescence recovery after photobleaching analysis showed that MreB filaments have a higher turnover in B. subtilis cells than in E. coli cells, indicating different filament kinetics in homologous or heterologous cell systems. The data show that MreB can direct the localization of EF-Tu in vivo, which in turn positively affects the formation and dynamics of MreB filaments. Thus, EF-Tu is a modulator of the activity of a bacterial actin-like protein.

KEYWORDS:

MreB; actin; bacterial cytoskeleton; translation factor Tu

PMID:
25676310
DOI:
10.1016/j.jmb.2015.01.025
[Indexed for MEDLINE]
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