Malfolded recombinant Tat substrates are Tat-independently degraded in Escherichia coli

Lindenstrauß, Ute; Matos, Cristina F.R.O.; Graubner, Wenke; Robinson, Colin; Brüser, Thomas

doi:10.1016/j.febslet.2010.07.039

« Previous Next »FEBS Letters
Volume 584, Issue 16 , Pages 3644-3648, 20 August 2010

Malfolded recombinant Tat substrates are Tat-independently degraded in Escherichia coli

Edited by Stuart Ferguson

Ute Lindenstrauß
- Institute of Biology/Microbiology, University of Halle-Wittenberg, Kurt-Mothes-Str. 3, D-06120 Halle, Germany
Cristina F.R.O. Matos
- Department of Biological Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
Wenke Graubner
- Institute of Biology/Microbiology, University of Halle-Wittenberg, Kurt-Mothes-Str. 3, D-06120 Halle, Germany
Colin Robinson
- Department of Biological Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
Thomas Brüser
- Institute of Biology/Microbiology, University of Halle-Wittenberg, Kurt-Mothes-Str. 3, D-06120 Halle, Germany
- Institute of Microbiology, Leibniz University Hannover, Schneiderberg 50, D-30167 Hannover, Germany
- Corresponding author at: Institute of Microbiology, Leibniz University Hannover, Schneiderberg 50, D-30167 Hannover, Germany. Fax: +49 511 762 5287.

Received 15 April 2010; received in revised form 20 July 2010; accepted 20 July 2010. published online 26 July 2010.

Abstract

The twin-arginine translocation (Tat) system translocates folded proteins across biological membranes. It has been suggested that the Tat system of Escherichia coli can direct Tat substrates to degradation if they are not properly folded [Matos, C.F., Robinson, C. and Di Cola, A. (2008) The Tat system proofreads FeS protein substrates and directly initiates the disposal of rejected molecules. EMBO J. 27, 2055–2063; Matos, C.F., Di Cola, A. and Robinson, C. (2009) TatD is a central component of a Tat translocon-initiated quality control system for exported FeS proteins in Escherichia coli. EMBO Rep. 10, 474–479]. Contrary to the earlier reports, it is now concluded that reported differences between tested strains were due to variations in expression levels and inclusion body formation. Using the native Tat substrate NrfC and a malfolded variant thereof, we show that the turnover of these proteins is not affected by the absence of all known Tat components. Malfolded NrfC is degraded more quickly than the native protein, indicating that Tat-independent protease systems can recognize malfolded Tat substrates.

Abbreviation: Tat, twin-arginine translocation

Keywords: Twin-arginine translocation system, Protein folding, Quality control, Protein transport, Protein degradation