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Rhoptries: an arsenal of secreted virulence factors

Peter J Bradley1, L David Sibley

  • 1Department of Microbiology, Immunology and Molecular Genetics, UCLA School of Medicine, Los Angeles, CA 90095, United States.

Current Opinion in Microbiology
|November 13, 2007
PubMed

Insights

Toxoplasma gondii rhoptry proteins (ROPs) are key virulence factors that manipulate host cells during invasion. Understanding these ROPs offers new strategies for disease prevention.

Area of Science:

  • * Molecular parasitology
  • * Cell biology
  • * Host-pathogen interactions

Background:

  • * Apicomplexan parasites, like *Toxoplasma gondii*, employ actin-based motility and organelle secretion for host cell invasion.
  • * Rhoptries are critical secretory organelles discharging contents during invasion, facilitating host cell entry and parasitophorous vacuole formation.
  • * Rhoptry Neck (RON) proteins are known to target the moving junction, a key structure in the invasion process.

Purpose of the Study:

  • * To identify and characterize novel rhoptry proteins (ROPs) in *Toxoplasma gondii*.
  • * To elucidate the diverse cellular destinations and functional roles of ROPs within the host cell.
  • * To investigate the role of ROP kinases as major parasite virulence factors influencing host gene expression.

Main Methods:

  • * Proteomic analysis of *Toxoplasma gondii* rhoptries to identify novel ROPs.
  • * Forward genetic analysis to determine the functional impact of ROP kinases.
  • * Investigation of ROP protein localization within host cells (nucleus, parasitophorous vacuole).

Main Results:

  • * Proteomic analysis revealed novel ROPs, including serine-threonine kinases and protein phosphatases.
  • * A subset of ROPs (RONs) localize to the moving junction, crucial for invasion.
  • * Secretory ROP kinases were identified as significant virulence factors, profoundly affecting host gene expression.

Conclusions:

  • * ROP proteins exhibit diverse targets and functions within host cells, analogous to bacterial effector proteins.
  • * ROP kinases are major virulence factors in *Toxoplasma gondii*, influencing host cell processes.
  • * Deciphering ROP effector functions provides potential targets for novel anti-parasitic disease interventions.

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