Dataset Information

The Toxoplasma gondii dense granule protein TgGRA3 interacts with host Golgi and dysregulates anterograde transport.

ABSTRACT: After entry into the host cell, the intracellular parasite Toxoplasma gondii resides within a membrane-bound compartment, the parasitophorous vacuole (PV). The PV defines an intracellular, parasite-specific niche surrounded by host organelles, including the Golgi apparatus. The mechanism by which T. gondii hijacks the host Golgi and subverts its functions remains unknown. Here, we present evidence that the dense granule protein TgGRA3 interacts with host Golgi, leading to the formation of tubules and the entry of host Golgi material into the PV. Targeted disruption of the TgGRA3 gene delays this engulfment of host Golgi. We also demonstrate that TgGRA3 oligomerizes and binds directly to host Golgi membranes. In addition, we show that TgGRA3 dysregulates anterograde transport in the host cell, thereby revealing one of the mechanisms employed by T. gondii to recruit host organelles and divert their functions. This article has an associated First Person interview with the first author of the paper.

SUBMITTER: Deffieu MS

PROVIDER: S-EPMC6451337 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

The Toxoplasma gondii dense granule protein TgGRA3 interacts with host Golgi and dysregulates anterograde transport.

Deffieu Maika S MS Alayi Tchilabalo Dilezitoko TD Slomianny Christian C Tomavo Stanislas S

Biology open 20190318 3

After entry into the host cell, the intracellular parasite Toxoplasma gondii resides within a membrane-bound compartment, the parasitophorous vacuole (PV). The PV defines an intracellular, parasite-specific niche surrounded by host organelles, including the Golgi apparatus. The mechanism by which T. gondii hijacks the host Golgi and subverts its functions remains unknown. Here, we present evidence that the dense granule protein TgGRA3 interacts with host Golgi, leading to the forma ...[more]

PMID: 30814066

Similar Datasets

Project description:Toxoplasma gondii infects approximately 30% of the world's population, causing disease primarily during pregnancy and in individuals with weakened immune systems. Toxoplasma secretes and exports effector proteins that modulate the host during infection, and several of these proteins are processed by the Golgi-associated aspartyl protease 5 (ASP5). Here, we identify ASP5 substrates by selectively enriching N-terminally derived peptides from wild-type and ?asp5 parasites. We reveal more than 2,000 unique Toxoplasma N-terminal peptides, mapping to both natural N termini and protease cleavage sites. Several of these peptides mapped directly downstream of the characterized ASP5 cleavage site, arginine-arginine-leucine (RRL). We validate candidates as true ASP5 substrates, revealing they are not processed in parasites lacking ASP5 or in wild-type parasites following mutation of the motif from RRL to ARL. All identified ASP5 substrates are dense granule proteins, and interestingly, none appear to be exported, thus differing from the analogous system in related Plasmodium spp. Instead we show that the majority of substrates reside within the parasitophorous vacuole (PV), and its membrane (the PVM), including two kinases and one phosphatase. We show that genetic deletion of WNG2 leads to attenuation in a mouse model, suggesting that this putative kinase is a new virulence factor in Toxoplasma Collectively, these data constitute the first in-depth analyses of ASP5 substrates and shed new light on the role of ASP5 as a maturase of dense granule proteins during the Toxoplasma lytic cycle.IMPORTANCE Toxoplasma gondii is one of the most successful human parasites. Central to its success is the arsenal of virulence proteins introduced into the infected host cell. Several of these virulence proteins require direct maturation by the aspartyl protease ASP5, and all require ASP5 for translocation into the host cell, yet the true number of ASP5 substrates and complete repertoire of effectors is currently unknown. Here we selectively enrich N-terminally derived peptides using Terminal Amine Isotopic Labeling of Substrates (TAILS) and use quantitative proteomics to reveal novel ASP5 substrates. We identify, using two different enrichment techniques, new ASP5 substrates and their specific cleavage sites. ASP5 substrates include two kinases and one phosphatase that reside at the host-parasite interface, which are important for infection.

Project description:Toxoplasma gondii evades host immunity to establish a chronic infection. Here, we assessed the role of parasitophorous vacuole (PV) membrane (PVM)- and intravacuolar network (IVN) membrane-localized dense granule (GRA) proteins in the development of acute and chronic Toxoplasma infection. Deletion of PVM-associated GRA3, GRA7, GRA8, and GRA14 or IVN membrane-associated GRA2, GRA9, and GRA12 in the low-virulence type II Prugniaud (Pru) strain induced severe defects in the development of chronic-stage cysts in vivo without affecting the parasite growth rate or the ability to differentiate into cysts in vitro Acute virulence of the Pru?gra2, Pru?gra3, and Pru?gra4 mutants was reduced but not abolished. In contrast, the Pru?gra12 mutant was avirulent in mice and Pru?gra12 parasites failed to establish a chronic infection. High-virulence type I strain RH?gra12 parasites also exhibited a major defect in acute virulence. In gamma interferon (IFN-?)-activated macrophages, type I RH?gra12 and type II Pru?gra12 parasites resisted the coating of the PVM with host immunity-related GTPases as effectively as the parental type I RH?ku80 and type II Pru?ku80 strains, respectively. Despite this resistance, ?gra12 PVs ultimately succumbed to IFN-?-activated host cell innate immunity. Our findings uncover a key role for GRA12 in mediating resistance to host IFN-? and reveal that many other IVN membrane-associated GRA proteins, as well as PVM-localized GRA proteins, play important roles in establishing chronic infection.IMPORTANCE Toxoplasma gondii cysts reactivate during immune deficiency and cause fatal encephalitis. Parasite molecules that coordinate the development of acute and chronic infection are poorly characterized. Here, we show that many intravacuolar network membrane and parasitophorous vacuole membrane-associated dense granule (GRA) proteins orchestrate the development of chronic cysts in vivo A subset of these GRA proteins also modulate acute virulence, and one protein that associates with the intravacuolar network membranes, namely GRA12, was identified as a major virulence factor required for parasite resistance to host gamma interferon (IFN-?). Our results revealed that many parasitophorous vacuole membrane and intravacuolar network membrane-associated GRA proteins are essential for successful chronic infection.

Dataset Information

The Toxoplasma gondii dense granule protein TgGRA3 interacts with host Golgi and dysregulates anterograde transport.

Publications

The <i>Toxoplasma gondii</i> dense granule protein TgGRA3 interacts with host Golgi and dysregulates anterograde transport.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets