Type I secretion in gram-negative bacteria

Biochim Biophys Acta. 2004 Nov 11;1694(1-3):149-61. doi: 10.1016/j.bbamcr.2004.05.001.


In gram-negative bacteria, type I secretion is carried out by a translocator made up of three proteins that span the cell envelope. One of these proteins is a specific outer membrane protein (OMP) and the other two are cytoplasmic membrane proteins: an ATP-binding cassette (ABC) and the so-called membrane fusion or adaptor protein (MFP). Type I secretion is sec-independent and bypasses the periplasm. This widespread pathway allows the secretion of proteins of diverse sizes and functions via a C-terminal uncleaved secretion signal. This C-terminal secretion signal specifically recognizes the ABC protein, triggering the assembly of the functional trans-envelope complex. This report will mainly deal will recent data concerning the structure and assembly of the secretion complex as well as the effects and role of substrate folding on secretion by this pathway.

Publication types

  • Review

MeSH terms

  • Amino Acid Sequence
  • Bacterial Outer Membrane Proteins / physiology
  • Bacterial Proteins / metabolism
  • Bacterial Proteins / physiology*
  • Escherichia coli Proteins
  • Gram-Negative Bacteria / physiology*
  • Membrane Transport Proteins / physiology*
  • Molecular Sequence Data
  • Protein Conformation
  • Protein Folding
  • Protein Transport / physiology


  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Escherichia coli Proteins
  • Membrane Transport Proteins
  • tolC protein, E coli