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- Title
A vacuolar- H<sup>+</sup>-pyrophosphatase ( TgVP1) is required for microneme secretion, host cell invasion, and extracellular survival of T oxoplasma gondii.
- Authors
Liu, Jing; Pace, Douglas; Dou, Zhicheng; King, Thayer P.; Guidot, Daniel; Li, Zhu‐Hong; Carruthers, Vern B.; Moreno, Silvia N. J.
- Abstract
The vacuolar proton pyrophosphatase ( H+- PPase) of T oxoplasma gondii ( TgVP1), a membrane proton pump, localizes to acidocalcisomes and a novel lysosome-like compartment termed plant-like vacuole ( PLV) or vacuolar compartment ( VAC). We report the characterization of a T . gondii null mutant for the TgVP1 gene. Propagation of these mutants decreased significantly because of deficient attachment and invasion of host cells, which correlated with deficient microneme secretion. Processing of cathepsin L ( CPL) in these mutants was deficient only when the parasites were incubated in the presence of low concentrations of the vacuolar H+- ATPase ( V- H+- ATPase) inhibitor bafilomycin A1, suggesting that either TgVP1 or the T . gondii V- H+- ATPase ( TgVATPase) are sufficient to support CPL processing. The lack of TgVP1 did not affect processing of micronemal proteins, indicating that it does not contribute to pro MIC maturations. The TgVP1 null mutants were more sensitive to extracellular conditions and were less virulent in mice. We demonstrate that T . gondii tachyzoites possess regulatory volume decrease capability during hypo-osmotic stress and this ability is impaired in TgVP1 null mutants implicating TgVP1 in osmoregulation. We hypothesize that osmoregulation is needed for host cell invasion and that TgVP1 plays a role during the normal lytic cycle of T . gondii.
- Subjects
TOXOPLASMA gondii; INORGANIC pyrophosphatase; CATHEPSINS; OSMOREGULATION; PROTEIN research; PATHOGENIC microorganisms; SECRETION
- Publication
Molecular Microbiology, 2014, Vol 93, Issue 4, p698
- ISSN
0950-382X
- Publication type
Article
- DOI
10.1111/mmi.12685