Phage shock protein PspA of Escherichia coli relieves saturation of protein export via the Tat pathway

J Bacteriol. 2004 Jan;186(2):366-73. doi: 10.1128/JB.186.2.366-373.2004.


Overexpression of either heterologous or homologous proteins that are routed to the periplasm via the twin-arginine translocation (Tat) pathway results in a block of export and concomitant accumulation of the respective protein precursor in the cytoplasm. Screening of a plasmid-encoded genomic library for mutants that confer enhanced export of a TorA signal sequence (ssTorA)-GFP-SsrA fusion protein, and thus result in higher cell fluorescence, yielded the pspA gene encoding phage shock protein A. Coexpression of pspA relieved the secretion block observed with ssTorA-GFP-SsrA or upon overexpression of the native Tat proteins SufI and CueO. A similar effect was observed with the Synechocystis sp. strain PCC6803 PspA homologue, VIPP1, indicating that the role of PspA in Tat export may be phylogenetically conserved. Mutations in Tat components that completely abolish export result in a marked induction of PspA protein synthesis, consistent with its proposed role in enhancing protein translocation via Tat.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis Proteins / physiology
  • Bacterial Proteins / physiology*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins / physiology*
  • Heat-Shock Proteins / physiology*
  • Membrane Proteins / physiology
  • Membrane Transport Proteins / physiology*
  • Mutation
  • Protein Transport


  • Arabidopsis Proteins
  • Bacterial Proteins
  • Escherichia coli Proteins
  • Heat-Shock Proteins
  • Membrane Proteins
  • Membrane Transport Proteins
  • VIPP1 protein, Arabidopsis
  • phage shock protein, Bacteria
  • twin-arginine translocase complex, E coli