Membrane protein insertion and proton-motive-force-dependent secretion through the bacterial holo-translocon SecYEG-SecDF-YajC-YidC

Ryan J. Schulze, Joanna Komar, Mathieu Botte, William J. Allen, Sarah Whitehouse, Vicki A. M. Gold, Jelger A. Lycklama A. Nijeholtb, Karine Huard, Imre Berger, Christiane Schaffitzel*, Ian Collinson

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

74 Citations (Scopus)

Abstract

The SecY/61 complex forms the protein-channel component of the ubiquitous protein secretion and membrane protein insertion apparatus. The bacterial version SecYEG interacts with the highly conserved YidC and SecDF-YajC subcomplex, which facilitates translocation into and across the membrane. Together, they form the holo-translocon (HTL), which we have successfully over-expressed and purified. In contrast to the homo-dimeric SecYEG, the HTL is a hetero-dimer composed of single copies of SecYEG and SecDF-YajC-YidC. The activities of the HTL differ from the archetypal SecYEG complex. It is more effective in cotranslational insertion of membrane proteins and the posttranslational secretion of a beta-barreled outer-membrane protein driven by SecA and ATP becomes much more dependent on the proton-motive force. The activity of the translocating copy of SecYEG may therefore be modulated by association with different accessory subcomplexes: SecYEG (forming SecYEG dimers) or SecDF-YajC-YidC (forming the HTL). This versatility may provide a means to refine the secretion and insertion capabilities according to the substrate. A similar modularity may also be exploited for the translocation or insertion of a wide range of substrates across and into the endoplasmic reticular and mitochondrial membranes of eukaryotes.

Original languageEnglish
Pages (from-to)4844-4849
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume111
Issue number13
DOIs
Publication statusPublished - 1 Apr 2014

Structured keywords

  • Bristol BioDesign Institute

Keywords

  • PF3 COAT PROTEIN
  • ESCHERICHIA-COLI
  • PREPROTEIN TRANSLOCATION
  • COMPLEX
  • CHANNEL
  • SUBSTRATE
  • COMPONENT
  • RIBOSOME
  • REQUIRES
  • SUBUNIT

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