TY - JOUR

T1 - The Tat system for membrane translocation of folded proteins recruits the membrane-stabilizing Psp machinery in Escherichia coli

AU - Mehner, Denise

AU - Osadnik, Hendrik

AU - Lünsdorf, Heinrich

AU - Brüser, Thomas

N1 - Copyright: Copyright 2012 Elsevier B.V., All rights reserved.

PY - 2012/8/10

Y1 - 2012/8/10

N2 - Tat systems transport folded proteins across energized membranes of bacteria, archaea, and plant plastids. In Escherichia coli, TatBC complexes recognize the transported proteins, and TatA complexes are recruited to facilitate transport. We achieved an abstraction of TatA from membranes without use of detergents and observed a co-purification of PspA, a mem-brane- stress response protein. The N-terminal transmembrane domain of TatA was required for the interaction. Electron microscopy displayed TatA complexes in direct contact with PspA. PspB and PspC were important for the TatA-PspA contact. The activator protein PspF was not involved in the PspATatA interaction, demonstrating that basal levels of PspA already interact with TatA. Elevated TatA levels caused membrane stress that induced a strictly PspBC- and PspF-dependent up-regulation of PspA. TatA complexes were found to destabilize membranes under these conditions. At native TatA levels, PspA deficiency clearly affected anaerobic TMAO respiratory growth, suggesting that energetic costs for transport of large Tat substrates such as TMAO reductase can become growth limiting in the absence of PspA. The physiological role of PspA recruitment to TatA may therefore be the control of membrane stress at active translocons.

AB - Tat systems transport folded proteins across energized membranes of bacteria, archaea, and plant plastids. In Escherichia coli, TatBC complexes recognize the transported proteins, and TatA complexes are recruited to facilitate transport. We achieved an abstraction of TatA from membranes without use of detergents and observed a co-purification of PspA, a mem-brane- stress response protein. The N-terminal transmembrane domain of TatA was required for the interaction. Electron microscopy displayed TatA complexes in direct contact with PspA. PspB and PspC were important for the TatA-PspA contact. The activator protein PspF was not involved in the PspATatA interaction, demonstrating that basal levels of PspA already interact with TatA. Elevated TatA levels caused membrane stress that induced a strictly PspBC- and PspF-dependent up-regulation of PspA. TatA complexes were found to destabilize membranes under these conditions. At native TatA levels, PspA deficiency clearly affected anaerobic TMAO respiratory growth, suggesting that energetic costs for transport of large Tat substrates such as TMAO reductase can become growth limiting in the absence of PspA. The physiological role of PspA recruitment to TatA may therefore be the control of membrane stress at active translocons.

UR - http://www.scopus.com/inward/record.url?scp=84865031049&partnerID=8YFLogxK

U2 - 10.1074/jbc.M112.374983

DO - 10.1074/jbc.M112.374983

M3 - Article

C2 - 22689583

AN - SCOPUS:84865031049

VL - 287

SP - 27834

EP - 27842

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 33

ER -