Affinage · Toxoplasma gondii

ROP17

rhoptry protein ROP17 · UniProt A0A125YN45

Annotated
2026-09-08
34 papers in source corpus 13 papers cited in narrative 13 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

ROP17 is a rhoptry-secreted serine/threonine kinase of Toxoplasma gondii that operates from the host-cytosolic face of the parasitophorous vacuole membrane (PVM) to disarm host innate immunity and to sustain parasite virulence and dissemination (PMID:24832449, PMID:31366709). It assembles into a complex with the pseudokinase ROP5 and the kinase ROP18, in which ROP5 binds adjacent to the nucleotide-binding domain of host immunity-related GTPases (IRGs) and produces an allosteric change that reorients target threonines in switch region I for phosphorylation by ROP17 and ROP18; this phosphorylation blocks IRG recruitment to the vacuole and protects the parasite from clearance in interferon-activated macrophages (PMID:24832449, PMID:25118287). Independently of its IRG-directed activity, ROP17 kinase activity is required for translocation of dense-granule (GRA) effectors across the PVM, functioning together with MYR1/MYR2/MYR3 and ASP5 in the export machinery (PMID:31366709, PMID:32075880). ROP17 also enhances Rho-ROCK-dependent interstitial migration of parasitized monocytes, promoting early systemic dissemination in vivo (PMID:31332383), and its loss attenuates virulence and reduces chronic tissue cyst burdens (PMID:27165797, PMID:27450947).

Mechanistic history

Synthesis pass · year-by-year structured walk · 12 steps
  1. 2014 High

    Established that ROP17 is an active kinase partnered with ROP5 and ROP18, defining the molecular basis for how the parasite neutralizes host IRG-mediated clearance.

    Evidence TAP purification, Co-IP, biochemical kinase assays and IRG recruitment assays in interferon-activated macrophages

    PMID:24832449

    Open questions at the time
    • Did not resolve the relative contributions of ROP17 versus ROP18 to individual IRG threonines
    • In vivo relevance of the complex not addressed in this study
  2. 2014 High

    Resolved how ROP5 primes IRG substrates, showing it induces an allosteric conformational change that reorients the target threonines for ROP17/ROP18 phosphorylation.

    Evidence Structural and biochemical analysis of the ROP5-IRG interaction

    PMID:25118287

    Open questions at the time
    • No direct co-structure of ROP17 with IRG
    • Kinetics of ROP17-specific phosphorylation not quantified
  3. 2014 Low

    First demonstration in a heterologous system that ROP17 is a functional serine/threonine kinase acting on a host substrate (c-Jun) and modulating apoptosis.

    Evidence HEK293T overexpression, Western blot for c-Jun phosphorylation, flow-cytometry apoptosis assay

    PMID:24822361

    Open questions at the time
    • Heterologous overexpression without parasite-context validation
    • c-Jun as a physiological ROP17 substrate not established
    • Single method per claim
  4. 2016 High

    Genetic dissection revealed that ROP17 contributes to virulence and chronic cyst burden through an IRG-independent mechanism, decoupling its in vivo importance from IRG protection.

    Evidence Targeted ROP17 deletion in type II, combined Δrop17/Δrop5 and Δrop17/Δrop18, mouse virulence, IRG recruitment and cyst-burden assays

    PMID:27165797

    Open questions at the time
    • Molecular basis of the IRG-independent virulence function not identified here
    • Host targets of this alternate function unknown
  5. 2016 Medium

    Confirmed a role for ROP17 in chronic-stage cyst persistence, uncovering genetic interaction with ROP21 while showing ROP17 loss alone does not impair in vitro growth or bradyzoite differentiation.

    Evidence CRISPR/Cas9 double knockout, mouse cyst-burden and in vitro growth/differentiation assays

    PMID:27450947

    Open questions at the time
    • Mechanism of the ROP17-ROP21 interaction unresolved
    • Single lab, limited orthogonal methods
  6. 2016 Medium

    Extended ROP17 virulence attenuation to a type I strain and probed genetic interaction with GRA7, indicating strain-dependent epistasis.

    Evidence CRISPR-Cas9 single and double knockouts, mouse virulence epistasis analysis

    PMID:27225000

    Open questions at the time
    • GRA7-ROP17 functional relationship not mechanistically defined
    • Limited to a single local strain
  7. 2016 Medium

    Linked ROP17 to activation of host innate immunity, showing it is required for the antitumor immune response elicited by attenuated parasites.

    Evidence Targeted deletion, tumor immunotherapy mouse model, antitumor immunity assay

    PMID:27447180

    Open questions at the time
    • Immune signaling pathway engaged by ROP17 not identified
    • Single lab
  8. 2016 Low

    Explored ROP17's host-cell manipulation via anti-apoptotic signaling, implicating c-Jun phosphorylation and Bcl-3 upregulation in macrophages.

    Evidence Overexpression in J774A.1 macrophages, flow cytometry, Western blot, c-Jun shRNA knockdown

    PMID:30141842

    Open questions at the time
    • Heterologous overexpression rather than parasite-delivered ROP17
    • Physiological relevance during infection unproven
    • Single signaling axis examined
  9. 2019 High

    Uncovered a distinct, IRG-independent function: ROP17 kinase activity is required for translocation of GRA effectors across the PVM and acts from the host-cytosolic side of the membrane.

    Evidence Whole-genome sequencing of translocation-defective mutants, null and catalytically dead mutants, trans-complementation, subcellular localization

    PMID:31366709

    Open questions at the time
    • Direct substrates of ROP17 in the translocation machinery not identified
    • How kinase activity mechanistically drives translocation unresolved
  10. 2019 High

    Assigned ROP17 a role in parasite dissemination, showing it enhances Rho-ROCK-dependent interstitial migration of parasitized monocytes and accelerates early spread in vivo.

    Evidence ROP17 knockout parasites, in vitro monocyte migration assays, in vivo mouse dissemination assay

    PMID:31332383

    Open questions at the time
    • Host substrate linking ROP17 to Rho-ROCK activation unknown
    • Whether kinase activity is required for the migration phenotype not stated
  11. 2020 High

    Placed ROP17 within the defined GRA translocation complex alongside MYR1/MYR2/MYR3 and ASP5, integrating it into the effector-export machinery.

    Evidence MYR1 affinity purification/Co-IP, genetic knockouts, GRA16 translocation assay

    PMID:32075880

    Open questions at the time
    • Direct physical link between ROP17 and MYR1 versus indirect association not distinguished
    • Stoichiometry and architecture of the complex undefined
  12. 2020 Medium

    Positioned GRA60 relative to the ROP5/ROP17/ROP18 virulence complex, showing it contributes to IRG resistance in parallel with or upstream of the complex.

    Evidence Genetic knockout, Co-IP of GRA60 with ROP18, IRG (Irgb10, Irga6) recruitment assays

    PMID:33040458

    Open questions at the time
    • Direct interaction of GRA60 with ROP17 not tested
    • Epistatic ordering only inferred from recruitment phenotypes

Open questions

Synthesis pass · forward-looking unresolved questions
  • The host substrates and mechanistic events by which ROP17 drives GRA translocation, monocyte hypermigration, and IRG-independent virulence remain to be identified.
  • No identified ROP17 substrate for the translocation or migration functions
  • Mechanistic link between kinase activity and Rho-ROCK signaling unknown
  • Physiological relevance of heterologous-system anti-apoptotic/autophagy findings during infection unestablished

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Complex memberships
MYR1/MYR2/MYR3/ASP5/ROP17 GRA translocation machineryROP5-ROP17-ROP18 virulence complex

Evidence

Reading pass · 13 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2014 ROP5 complexes with the active kinases ROP18 and ROP17, as demonstrated by tandem affinity protein tagging and purification in T. gondii. Biochemical analyses indicate that ROP18 and ROP17 have evolved to target adjacent and essential threonine residues in switch region I of immunity-related GTPases (IRGs). The combined activities of ROP17 and ROP18 contribute to avoidance of IRG recruitment to the intracellular T. gondii-containing vacuole, protecting the parasite from clearance in interferon-activated macrophages. Tandem affinity purification (TAP tagging), Co-IP, biochemical kinase assay, IRG recruitment assay in interferon-activated macrophages Cell host & microbe High 24832449
2014 ROP5 binds adjacent to the nucleotide-binding domain of an IRG, producing an allosteric change that alters the orientation of two threonine residues targeted by Toxoplasma kinases ROP17 and ROP18, thereby facilitating their phosphorylation by ROP17/ROP18. Structural and biochemical analyses of ROP5-IRG interaction, allosteric conformational analysis The Journal of biological chemistry High 25118287
2019 ROP17 is required for enhanced tissue migration of parasitized monocytes and macrophages through collagen-rich tissues in a Rho-ROCK-dependent manner consistent with integrin-independent interstitial migration. ROP17-deficient parasites failed to upregulate monocyte tissue migration and exhibited an early dissemination delay in vivo. ROP17 knockout parasites, in vitro monocyte migration assays (endothelial and collagen matrix), in vivo mouse dissemination assay Nature microbiology High 31332383
2019 ROP17 kinase activity is required for translocation of dense granule (GRA) effector proteins across the parasitophorous vacuolar membrane (PVM). Null or catalytically dead (kinase-dead) mutants of ROP17 are defective in GRA translocation. ROP17 resides on the host cytosol side of the PVM and carries out its translocation function from this location, as demonstrated by trans-complementation with ROP17 delivered by co-infecting tachyzoites. Whole-genome sequencing of translocation-defective mutants, null mutant and catalytically dead mutant analysis, trans-complementation assay, subcellular localization mSphere High 31366709
2020 ROP17 was identified as one of five parasite proteins required for translocation of GRA effectors across the PVM, alongside MYR1, MYR2, MYR3, and ASP5. Co-immunoprecipitation of MYR1 confirmed its association within this translocation complex. Affinity purification of MYR1 (Co-IP), genetic knockouts, GRA16 translocation assay mSphere High 32075880
2016 Deletion of ROP17 in type II T. gondii resulted in a >12-fold defect in virulence in mice; however, resistance to host IRGs was not affected in the Δrop17 strain. Combined Δrop17/Δrop5 and Δrop17/Δrop18 showed that ROP17 contributes to virulence via an IRG-independent mechanism. Deletion of ROP17 severely reduced tissue cyst burdens in chronic infection. Gene knockout (targeted deletion of 26 ROPK loci), mouse virulence assay, IRG recruitment assay, cyst burden quantification mBio High 27165797
2016 Combined Δrop21/Δrop17 double knockout led to a 50% reduction in cyst burden in vivo in chronic infection, whereas single Δrop17 knockout had no effect on in vitro growth or bradyzoite differentiation. CRISPR/Cas9 gene deletion, mouse cyst burden assay, in vitro growth assay Cellular microbiology Medium 27450947
2020 GRA60, a dense granule protein, associates with ROP18 (a member of the ROP5/ROP17/ROP18 virulence complex) and contributes to resistance against IRG recruitment to the PVM. Deletion of GRA60 in RHΔrop5 background showed IRG recruitment comparable to single knockouts, indicating GRA60 functions in parallel with or upstream of the ROP5/ROP17/ROP18 complex. Genetic knockout, Co-immunoprecipitation (GRA60 with ROP18), IRG recruitment assay (Irgb10, Irga6) Cellular microbiology Medium 33040458
2016 Deletion of ROP17 in a type II T. gondii strain severely abrogated the antitumor immune response induced by uracil auxotrophic mutants, indicating ROP17 plays a role in activating host innate immune responses through parasitophorous vacuole membrane-associated functions. Targeted gene deletion, tumor immunotherapy mouse model, antitumor immunity assay PLoS genetics Medium 27447180
2014 TgROP17 expressed in HEK 293T cells phosphorylates c-Jun, demonstrating serine/threonine kinase activity. ROP17 overexpression also inhibited camptothecin-induced apoptosis. Eukaryotic expression vector transfection, Western blotting for c-Jun phosphorylation, flow cytometry apoptosis assay Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi Low 24822361
2016 ROP17 overexpression in J774A.1 macrophages inhibited IFN-γ-induced apoptosis via phosphorylation of c-Jun and upregulation of Bcl-3; this anti-apoptotic effect was dependent on c-Jun phosphorylation as shown by c-Jun shRNA knockdown. Plasmid transfection, flow cytometry, Western blotting for phospho-c-Jun, Bcl-3, cleaved Caspase-3, c-Jun shRNA knockdown Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi Low 30141842
2021 ROP17 interacts with Bcl-2 as demonstrated by co-immunoprecipitation, and ROP17 overexpression promotes autophagy via the Bcl-2–Beclin 1 pathway in HEK 293T cells. Co-immunoprecipitation, MDC staining, transmission electron microscopy, fluorescence microscopy, Western blotting, immunohistochemistry in vivo Folia parasitologica Low 34180401
2016 Deletion of ROP17 individually in a Chinese type I strain (T.gHB1) showed similar virulence attenuation as in the RH strain, but double deletions of GRA7 plus ROP17 in T.gHB1 did not show significant further attenuation compared to the ROP17 single knockout, suggesting ROP17 and GRA7 may not act independently in all strain backgrounds. CRISPR-Cas9 gene deletion, mouse virulence assay, double knockout epistasis analysis Parasitology research Medium 27225000

Source papers

Stage 0 corpus · 34 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2014 The Toxoplasma pseudokinase ROP5 forms complexes with ROP18 and ROP17 kinases that synergize to control acute virulence in mice. Cell host & microbe 202 24832449
2015 The ROP18 and ROP5 gene allele types are highly predictive of virulence in mice across globally distributed strains of Toxoplasma gondii. International journal for parasitology 95 26699401
2016 The Toxoplasma gondii Rhoptry Kinome Is Essential for Chronic Infection. mBio 69 27165797
2014 The Toxoplasma pseudokinase ROP5 is an allosteric inhibitor of the immunity-related GTPases. The Journal of biological chemistry 60 25118287
2019 The secreted kinase ROP17 promotes Toxoplasma gondii dissemination by hijacking monocyte tissue migration. Nature microbiology 55 31332383
2020 Coimmunoprecipitation with MYR1 Identifies Three Additional Proteins within the Toxoplasma gondii Parasitophorous Vacuole Required for Translocation of Dense Granule Effectors into Host Cells. mSphere 53 32075880
2019 Translocation of Dense Granule Effectors across the Parasitophorous Vacuole Membrane in Toxoplasma-Infected Cells Requires the Activity of ROP17, a Rhoptry Protein Kinase. mSphere 50 31366709
2016 Secretion of Rhoptry and Dense Granule Effector Proteins by Nonreplicating Toxoplasma gondii Uracil Auxotrophs Controls the Development of Antitumor Immunity. PLoS genetics 47 27447180
2019 Comparative virulence of Caribbean, Brazilian and European isolates of Toxoplasma gondii. Parasites & vectors 34 30871587
2020 The unicellular eukaryotic parasite Toxoplasma gondii hijacks the migration machinery of mononuclear phagocytes to promote its dissemination. Biology of the cell 27 32359185
2017 Association of ROP18 and ROP5 was efficient as a marker of virulence in atypical isolates of Toxoplasma gondii obtained from pigs and goats in Piauí, Brazil. Veterinary parasitology 27 29080759
2014 Partial protective effect of intranasal immunization with recombinant Toxoplasma gondii rhoptry protein 17 against toxoplasmosis in mice. PloS one 27 25255141
2016 Secreted protein kinases regulate cyst burden during chronic toxoplasmosis. Cellular microbiology 25 27450947
2020 Toxoplasma gondii GRA60 is an effector protein that modulates host cell autonomous immunity and contributes to virulence. Cellular microbiology 24 33040458
2016 DNA vaccination with a gene encoding Toxoplasma gondii Rhoptry Protein 17 induces partial protective immunity against lethal challenge in mice. Parasite (Paris, France) 21 26842927
2018 Atypical virulence in a type III Toxoplasma gondii strain isolated in Japan. Parasitology international 20 29775826
2019 Toxoplasma gondii ROP17 inhibits the innate immune response of HEK293T cells to promote its survival. Parasitology research 16 30675671
2021 Comparative Proteomics Analysis for Elucidating the Interaction Between Host Cells and Toxoplasma gondii. Frontiers in cellular and infection microbiology 14 34055664
2016 Analysis of the virulence determination mechanisms in a local Toxoplasma strain (T.gHB1) isolated from central China. Parasitology research 9 27225000
2023 Genotyping of toxoplasma gondii isolates from México reveals non-archetypal and potentially virulent strains for mice. Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases 8 37353185
2014 Sequence variation in Toxoplasma gondii rop17 gene among strains from different hosts and geographical locations. TheScientificWorldJournal 8 25126596
2024 Vaccination with a DNA vaccine cocktail encoding TgROP2, TgROP5, TgROP9, TgROP16, TgROP17, and TgROP18 confers limited protection against Toxoplasma gondii in BALB/c mice. Parasitology research 7 39724445
2021 Toxoplasma gondii ROP17 promotes autophagy via the Bcl-2-Beclin 1 pathway. Folia parasitologica 7 34180401
2024 Rapid genotyping of Toxoplasma gondii isolates via Nanopore-based multi-locus sequencing. AMB Express 5 38844693
2015 MSCA: a spectral comparison algorithm between time series to identify protein-protein interactions. BMC bioinformatics 5 25963052
2024 Genotyping of Toxoplasma gondii in domestic animals from Campeche, México, reveals virulent genotypes and a recombinant ROP5 allele. Parasitology 4 38379406
2014 Toxoplasma's arms race with the host interferon response: a ménage à trois of ROPs. Cell host & microbe 4 24832444
2014 [Construction, expression and kinase function analysis of an eukaryocyte vector of rhoptry protein 17 in Toxoplasma gondii]. Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi = Chinese journal of parasitology & parasitic diseases 3 24822361
2025 Investigation of Virulence-Related Markers in Atypical Strains of Toxoplasma gondii from Brazil. Microorganisms 2 40005667
2025 New genetic variants of Toxoplasma gondii isolates and a novel ROP5 allele in free-range chickens from Tabasco, México. Parasitology 2 40588766
2016 [Toxoplasma gondii Rhoptry Protein 17 Inhibits the Apoptosis of Mouse Macrophages via Activation of Activator Protein 1 Signaling]. Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi = Chinese journal of parasitology & parasitic diseases 1 30141842
2012 Gene-cloning, expression and antigenicity analysis of rhoptry protein 17 of Toxoplasma gondii. Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi = Chinese journal of parasitology & parasitic diseases 1 22913185
2019 Neighbors Working Together: a Toxoplasma Rhoptry Protein That Facilitates Dense Granule Protein Translocation into the Host Cell. mSphere 0 31366706
2015 [Research Advance on Toxoplasma gondii Rhoptry Protein 2 Family as Candidate Vaccine Molecules]. Zhongguo ji sheng chong xue yu ji sheng chong bing za zhi = Chinese journal of parasitology & parasitic diseases 0 26541043