Bacterial Type IV secretion systems: versatile virulence machines

Future Microbiol. 2012 Feb;7(2):241-57. doi: 10.2217/fmb.11.150.


Many bacterial pathogens employ multicomponent protein complexes to deliver macromolecules directly into their eukaryotic host cell to promote infection. Some Gram-negative pathogens use a versatile Type IV secretion system (T4SS) that can translocate DNA or proteins into host cells. T4SSs represent major bacterial virulence determinants and have recently been the focus of intense research efforts designed to better understand and combat infectious diseases. Interestingly, although the two major classes of T4SSs function in a similar manner to secrete proteins, the translocated 'effectors' vary substantially from one organism to another. In fact, differing effector repertoires likely contribute to organism-specific host cell interactions and disease outcomes. In this review, we discuss the current state of T4SS research, with an emphasis on intracellular bacterial pathogens of humans and the diverse array of translocated effectors used to manipulate host cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Bacterial Proteins / metabolism
  • Bacterial Secretion Systems*
  • DNA, Bacterial / metabolism
  • Gram-Negative Bacteria / genetics
  • Gram-Negative Bacteria / metabolism
  • Gram-Negative Bacteria / pathogenicity*
  • Gram-Negative Bacterial Infections / microbiology
  • Host-Pathogen Interactions
  • Humans
  • Protein Transport
  • Signal Transduction
  • Species Specificity
  • Transcription, Genetic
  • Ubiquitination
  • Virulence Factors / metabolism*


  • Bacterial Proteins
  • Bacterial Secretion Systems
  • DNA, Bacterial
  • Virulence Factors