Toxoplasma gondii MAF1b Binds the Host Cell MIB Complex To Mediate Mitochondrial Association

Kelly, Felice D.; Weinhammer, Annika; Cygan, Alicja M.; Parker, Michelle; Boulanger, Martin J.; Boothroyd, John C.

doi:10.1128/msphere.00183-17

Cited by 21 publications

(29 citation statements)

References 52 publications

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“…94 . Rabbit polyclonal anti-GRA7 95 , anti-MAF1 96 , and anti-SAG1 antibodies were kindly provided by Dr. John C. Boothroyd. Rat anti-HA (3F10) antibodies were obtained from Sigma-Aldrich (Cat#11867431001).…”

Section: Methodsmentioning

confidence: 99%

“…MAF1 localization was observed in the HFFs infected wild-type, Δ gra45 parasites or Δ gra45 parasites complemented with wild-type or mutant versions of GRA45 . At 4 or 24 h post-infection, the cells were fixed with 4% PFA, permeabilized/blocked with PBS containing 3% (w/v) BSA, 5% (v/v) goat serum and 0.1% Triton X-100 followed by incubation with MAF1 antibodies 96 . To check the PVM localization of GRA23 or export of GRA16 and GRA24, HFFs grown on glass coverslips were infected with wild-type, Δ myr1 , Δ gra45 parasites or Δ gra45 parasites complemented with wild-type or mutant versions of GRA45 transiently expressing GRA23-HA-FLAG, GRA16-HA-FLAG, or GRA16-Ty 50 , GRA24-HA-FLAG or GRA24-Ty 50 for 20–24 h followed by fixation, permeabilization and blocking as described above.…”

Section: Methodsmentioning

confidence: 99%

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Genome-wide screens identify Toxoplasma gondii determinants of parasite fitness in IFNγ-activated murine macrophages

et al. 2020

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Macrophages play an essential role in the early immune response against Toxoplasma and are the cell type preferentially infected by the parasite in vivo. Interferon gamma (IFNγ) elicits a variety of anti-Toxoplasma activities in macrophages. Using a genome-wide CRISPR screen we identify 353 Toxoplasma genes that determine parasite fitness in naїve or IFNγ-activated murine macrophages, seven of which are further confirmed. We show that one of these genes encodes dense granule protein GRA45, which has a chaperone-like domain, is critical for correct localization of GRAs into the PVM and secretion of GRA effectors into the host cytoplasm. Parasites lacking GRA45 are more susceptible to IFNγ-mediated growth inhibition and have reduced virulence in mice. Together, we identify and characterize an important chaperone-like GRA in Toxoplasma and provide a resource for the community to further explore the function of Toxoplasma genes that determine fitness in IFNγ-activated macrophages.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Genome-wide screens identify Toxoplasma gondii determinants of parasite fitness in IFNγ-activated murine macrophages

et al. 2020

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“…In T. gondii , we and others have identified the parasite locus that is required for host mitochondrial association (HMA), mitochondrial association factor 1B ( MAF1b ) and shown that expression of MAF1b increases cytokine signaling (Pernas et al ., ) during the acute phase of in vivo infections. In infected cell lysates and cells expressing MAF1b ectopically, MAF1b protein interacts with host mitochondrial outer membrane proteins belonging to the MICOS complex, which may be involved in the ability of MAF1b to mediate HMA (Kelly et al ., ). During the acute phase of mouse infections, MAF1b‐expressing parasites outcompete their MAF1b‐null counterparts (Adomako‐Ankomah et al ., ), implying that MAF1b plays an important role in determining infection outcome.…”

Section: Introductionmentioning

confidence: 97%

A Toxoplasma gondii locus required for the direct manipulation of host mitochondria has maintained multiple ancestral functions

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Parker

Ramaswamy

et al. 2018

Molecular Microbiology

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Summary The Toxoplasma gondii locus mitochondrial association factor 1 (MAF1) encodes multiple paralogs, some of which mediate host mitochondrial association (HMA). Previous work showed that HMA was a trait that arose in T. gondii through neofunctionalization of an ancestral MAF1 ortholog. Structural analysis of HMA-competent and incompetent MAF1 paralogs (MAF1b and MAF1a, respectively) revealed that both paralogs harbor an ADP ribose binding macro domain, with comparatively low (micromolar) affinity for ADP ribose. Replacing the 16 C-terminal residues of MAF1b with those of MAF1a abrogated HMA, and we also show that only three residues in the C-terminal helix are required for MAF1-mediated HMA. Importantly these same three residues are also required for the in vivo growth advantage conferred by MAF1b, providing a definitive link between in vivo proliferation and manipulation of host mitochondria. Co-immunoprecipitation assays reveal that the ability to interact with the mitochondrial MICOS complex is shared by HMA-competent and incompetent MAF1 paralogs and mutants. The weak ADPr coordination and ability to interact with the MICOS complex shared between divergent paralogs may represent modular ancestral functions for this tandemly expanded and diversified T. gondii locus.

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“…Studies demonstrated that host mitochondrion association is mediated by an interaction between T. gondii MAF1 and the host cell mitochondrial intermembrane space-bridging (MIB) complex (44). In this paper, we identify and characterize a novel E.…”

Section: Introductionmentioning

confidence: 99%

Microsporidia Interact with Host Cell Mitochondria via Voltage-Dependent Anion Channels Using Sporoplasm Surface Protein 1

Han

et al. 2019

mBio

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Microsporidia are opportunistic intracellular pathogens that can infect a wide variety of hosts ranging from invertebrates to vertebrates. During invasion, the microsporidian polar tube pushes into the host cell, creating a protective microenvironment, the invasion synapse, into which the sporoplasm extrudes. Within the synapse, the sporoplasm then invades the host cell, forming a parasitophorous vacuole (PV). Using a proteomic approach, we identified Encephalitozoon hellem sporoplasm surface protein 1 (EhSSP1), which localized to the surface of extruded sporoplasms. EhSSP1 was also found to interact with polar tube protein 4 (PTP4). Recombinant EhSSP1 (rEhSSP1) bound to human foreskin fibroblasts, and both anti-EhSSP1 and rEhSSP1 caused decreased levels of host cell invasion, suggesting that interaction of SSP1 with the host cell was involved in invasion. Coimmunoprecipitation (Co-IP) followed by proteomic analysis identified host cell voltage-dependent anion channels (VDACs) as EhSSP1 interacting proteins. Yeast two-hybrid assays demonstrated that EhSSP1 was able to interact with VDAC1, VDAC2, and VDAC3. rEhSSP1 colocalized with the host mitochondria which were associated with microsporidian PVs in infected cells. Transmission electron microscopy revealed that the outer mitochondrial membrane interacted with meronts and the PV membrane, mitochondria clustered around meronts, and the VDACs were concentrated at the interface of mitochondria and parasite. Knockdown of VDAC1, VDAC2, and VDAC3 in host cells resulted in significant decreases in the number and size of the PVs and a decrease in mitochondrial PV association. The interaction of EhSSP1 with VDAC probably plays an important part in energy acquisition by microsporidia via its role in the association of mitochondria with the PV. IMPORTANCE Microsporidia are important opportunistic human pathogens in immune-suppressed individuals, such as those with HIV/AIDS and recipients of organ transplants. The sporoplasm is critical for establishing microsporidian infection. Despite the biological importance of this structure for transmission, there is limited information about its structure and composition that could be targeted for therapeutic intervention. Here, we identified a novel E. hellem sporoplasm surface protein, EhSSP1, and demonstrated that it can bind to host cell mitochondria via host VDAC. Our data strongly suggest that the interaction between SSP1 and VDAC is important for the association of mitochondria with the parasitophorous vacuole during microsporidian infection. In addition, binding of SSP1 to the host cell is associated with the final steps of invasion in the invasion synapse.

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Toxoplasma gondii MAF1b Binds the Host Cell MIB Complex To Mediate Mitochondrial Association

Cited by 21 publications

References 52 publications

Genome-wide screens identify Toxoplasma gondii determinants of parasite fitness in IFNγ-activated murine macrophages

Genome-wide screens identify Toxoplasma gondii determinants of parasite fitness in IFNγ-activated murine macrophages

A Toxoplasma gondii locus required for the direct manipulation of host mitochondria has maintained multiple ancestral functions

Microsporidia Interact with Host Cell Mitochondria via Voltage-Dependent Anion Channels Using Sporoplasm Surface Protein 1

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