Bacterial Virulence Factors and Rho GTPases

Volume 291 of the series Current Topics in Microbiology and Immunology pp 29-42

Triggered Phagocytosis by Salmonella: Bacterial Molecular Mimicry of RhoGTPase Activation/Deactivation

  • M. C. SchlumbergerAffiliated withInstitute of Microbiology, ETH Zürich
  • , W.-D. HardtAffiliated withInstitute of Microbiology, ETH Zürich

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Salmonella Typhimurium uses the type III secretion system encoded in the Salmonella pathogenicity island I (SPI-1 TTSS) to inject toxins (effector proteins) into host cells. Here, we focus on the functional mechanism of three of these toxins: SopE, SopE2, and SptP. All three effector proteins change the GTP/GDP loading state of RhoGTPases by transient interactions. SopE and SopE2 mimic eukaryotic G-nucleotide exchange factors and thereby activate RhoGTPase signaling pathways in infected host cells. In contrast, a domain of SptP inactivates RhoGTPases by mimicking the activity of eukaryotic GTPase-activating proteins. The Salmonella-host cell interaction provides an excellent example for the use of molecular mimicry by bacterial pathogens.