| 2008 |
P. falciparum RON2 (PfRON2) localizes to the neck portion of the rhoptry in merozoites, is transcribed at peak levels at the mature schizont stage, and forms a complex with PfRON4 and PfAMA1 as demonstrated by co-immunoprecipitation, establishing conservation of the moving junction complex between T. gondii and P. falciparum. Co-immunoprecipitation studies also showed that PfRON2 is NOT a component of the RhopH complex. |
Co-immunoprecipitation, immunofluorescence microscopy, transcriptional analysis |
Parasitology international |
Medium |
18952195
|
| 2010 |
The R1 invasion-inhibitory peptide binds the PfAMA1 hydrophobic trough and prevents PfAMA1 interaction with the PfRON complex (including RON2), placing the AMA1-RON2 interaction after merozoite reorientation and actomyosin motor engagement during the invasion sequence. |
Peptide-binding assays, invasion inhibition assays, epistasis/temporal ordering by sequential blocking |
The Journal of biological chemistry |
Medium |
20228060
|
| 2011 |
P. falciparum RON2 is inserted as an integral membrane protein in the host cell membrane during invasion. Using native and recombinant protein interaction assays, the extracellular region of RON2 that binds AMA1 was defined, and invasion inhibition assays confirmed that the RON2-AMA1 interaction is required for P. falciparum merozoite entry into erythrocytes. |
Integral membrane protein insertion assay, native and recombinant protein interaction assays, invasion inhibition assays |
PLoS pathogens |
High |
21347343
|
| 2011 |
The RON2 peptide binding site on AMA1 is its hydrophobic pocket. Two conserved, disulfide-linked cysteines in the RON2 peptide are critical residues required for binding to the AMA1 hydrophobic pocket. RON2-AMA1 binding triggers junction formation and commits P. falciparum merozoites to RBC invasion. The RON2 peptide blocked junction formation but, unlike AMA1-specific antibodies targeting the pocket, did not block parasitophorous vacuole formation, indicating junction formation and vacuole formation are molecularly distinct steps. |
Antibody blocking assays, AMA1 pocket mutants, RON2 peptide competition assays, live microscopy of junction and vacuole formation |
Proceedings of the National Academy of Sciences of the United States of America |
High |
21788485
|
| 2011 |
The C-terminal cysteine-rich domain of PfRON2 binds host erythrocytes (as shown by COS-7 surface rosetting assay), and both the C-terminal and central cysteine-rich domains of PfRON2 interact with PfAMA1; this binding can be inhibited by mAb 4G2 targeting the AMA1 hydrophobic groove, indicating the hydrophobic groove of PfAMA1 is the binding site for PfRON2. |
COS-7 surface expression rosetting assay, binding inhibition with monoclonal antibody |
Parasitology research |
Medium |
22033736
|
| 2011 |
PfRON2 also forms a complex with PfRON3 and PfRON4 (without PfAMA1), as shown by co-immunoprecipitation, constituting a novel RON complex (PfRON2/3/4) distinct from the moving junction complex (PfRON2/4/5/AMA1). |
Co-immunoprecipitation |
Parasitology international |
Low |
21237287
|
| 2012 |
Crystal structure of PfAMA1 in complex with a peptide derived from the extracellular region of PfRON2 was determined. The receptor-binding site of PfAMA1 comprises the hydrophobic groove and a region exposed by displacement of the flexible Domain II loop. Mutations of key contact residues in PfRON2 and PfAMA1 abrogate binding between the recombinant proteins. The PfRON2 peptide inhibits P. falciparum erythrocyte invasion, and this inhibitory potency is not affected by AMA1 polymorphisms. The R1 inhibitory peptide mimics the PfRON2 peptide structurally in binding to PfAMA1. |
X-ray crystallography, site-directed mutagenesis, binding assays, invasion inhibition assay |
PLoS pathogens |
High |
22737069
|
| 2012 |
In P. falciparum merozoites, RON2 (Rhoptry Neck Protein 2) is released early during invasion, following the junction, as determined by high-definition imaging of endogenously tagged proteins, supporting the model that RON2 is among the first rhoptry neck proteins secreted during invasion. |
Endogenous gene tagging, high-definition live and fixed fluorescence imaging |
PloS one |
Medium |
23049965
|
| 2013 |
A small molecule identified by high-throughput screening inhibits P. falciparum merozoite invasion by binding to AMA1 and blocking formation of the AMA1-RON2 complex; electron microscopy confirmed this inhibitor prevents tight junction formation, directly linking AMA1-RON2 complex formation to junction formation during invasion. |
High-throughput compound screening, binding assay, electron microscopy, invasion inhibition assay |
Nature communications |
High |
23907321
|
| 2015 |
Live cell imaging with systematic blocking of receptor-ligand interactions established the temporal sequence of invasion: the AMA1-RON2 interaction mediates tight junction formation, which acts as an anchor point for parasite internalization, occurring after the PfRh5-basigin binding step. |
Live cell imaging, genetic deletion, enzymatic receptor cleavage, inhibitory antibodies and peptides |
PLoS pathogens |
High |
25723550
|
| 2016 |
The Domain II (DII) loop of PfAMA1 kinetically stabilizes the PfAMA1-RON2 complex by lengthening the complex half-life 18-fold (from ~48 s to ~900 s at 25°C) by slowing the dissociation rate, as determined by fluorescence anisotropy kinetic and thermodynamic measurements comparing wild-type PfAMA1 and a ΔDII-loop engineered construct. |
Fluorescence anisotropy kinetics, isothermal titration calorimetry, engineered deletion mutant |
PloS one |
High |
26731670
|
| 2009 |
In P. berghei, RON2 (PBRON2) localizes to the rhoptries in merozoites and is also expressed in sporozoites with the same timing and apical rhoptry location as the known rhoptry protein RAP2/3, establishing RON2 rhoptry localization across both invasion stages. |
GFP/MYC epitope tagging, fluorescence microscopy, cross-lifecycle expression analysis |
Molecular and biochemical parasitology |
Medium |
19428669
|
| 2014 |
In P. yoelii sporozoites, RON2 and RON4 are lost following rhoptry discharge during entry into host cells (analogous to merozoite entry), and rhoptry discharge of RON2/RON4 in sporozoites requires the host membrane protein CD81, as sporozoites failed to discharge rhoptries in CD81-negative conditions. |
Transgenic P. yoelii expressing fluorescent RON2/RON4/RAP2-3, fluorescence microscopy, CD81-dependent entry assay |
Cellular microbiology |
Medium |
24798694
|
| 2018 |
In P. berghei, RON2 is localized to rhoptries in sporozoites. Sporozoite stage-specific knockdown of ron2 (by promoter swapping to restrict transcription to intraerythrocytic stages) severely impaired sporozoite invasion of mosquito salivary glands by decreasing attachment capacity, and also reduced infectivity to hepatocytes, demonstrating a functional role for RON2 in sporozoite invasion distinct from its role in merozoite invasion. |
Promoter swapping strategy for stage-specific knockdown, salivary gland invasion assay, hepatocyte infection assay, immunofluorescence |
Cellular microbiology |
High |
30307699
|
| 2019 |
In P. berghei sporozoites, RON2 localizes to rhoptries (confirmed by immuno-electron microscopy). Unlike merozoites where RON2 and RON4 are neck-restricted, most rhoptry neck proteins including RON2 localize throughout the rhoptries in sporozoites, indicating stage-specific differences in subcompartmentalization. |
Immuno-electron microscopy, immunofluorescence assay |
Frontiers in cellular and infection microbiology |
Medium |
31552198
|
| 2020 |
In P. berghei sporozoites, RON2, RON4, and RON5 form a complex (as demonstrated by co-immunoprecipitation from oocyst-derived sporozoite extracts). Stage-specific knockdown revealed that RON2 and RON4 reciprocally affect each other's trafficking to rhoptries in developing sporozoites, while RON5 is independently transported. RON4 and RON5 knockdown reduced sporozoite attachment and salivary gland invasion. |
Co-immunoprecipitation from sporozoite extracts, sporozoite stage-specific gene knockdown, salivary gland invasion assay, fluorescence microscopy |
mSphere |
High |
32817376
|
| 2022 |
In P. berghei, conditional DiCre-mediated deletion of RON2 (or RON4) in sporozoites impairs colonization of mosquito salivary glands and invasion of mammalian hepatocytes without affecting transcellular migration. 3D electron microscopy showed that absence of a functional AMA1-RON complex led to altered morphology of the entry junction, associated with epithelial cell damage, establishing that RON2 is required for forming a proper invasion junction in sporozoites. |
DiCre-mediated conditional gene deletion, mosquito salivary gland invasion assay, hepatocyte invasion assay, 3D electron microscopy |
PLoS pathogens |
High |
35731833
|
| 2021 |
In P. yoelii merozoites, PyRON2 was already present on the merozoite surface immediately after egress (prior to erythrocyte encounter), and its secretion was not affected by PKAc disruption, in contrast to AMA1. This is inconsistent with the model that RON2 is injected exclusively into the erythrocyte cytosol from within the host, suggesting RON2 may be exposed on the merozoite surface before invasion. |
DiCre-loxP inducible knockout of PKAc, immunofluorescence microscopy for RON2 localization at egress, erythrocyte invasion assay |
Parasitology international |
Medium |
34390881
|
| 2026 |
Cryo-EM structure of the endogenous P. falciparum moving junction purified from invasion-stalled parasites revealed a 1:1:1:1 assembly of PfAMA1 with PfRON2, PfRON4, and PfRON5. PfRON2 contains two transmembrane helices that anchor the complex in the red blood cell membrane and display an extracellular handle for PfAMA1 binding. PfAMA1 directly contacts the RBC membrane. PfRON2/4/5 form a large basic platform inside the RBC that electrostatically engages the RBC membrane and embeds amphipathic helices into the bilayer, suggesting RON2 participates in host membrane remodeling during invasion. |
Cryo-EM structural determination of endogenous complex purified from invasion-stalled P. falciparum, computational protein design of binder |
Cell |
High |
42379167
|
| 2025 |
Computational simulation of DII loop dynamics in the PfAMA1-PfRON2 complex identified key residues in the PfRON2 helix essential for the post-binding lock conformation. Experimental mutagenesis of these residues validated their functional importance in complex stabilization. |
Molecular dynamics simulation, mutagenesis with experimental binding validation |
Chembiochem : a European journal of chemical biology |
Medium |
40067319
|
| 2019 |
For P. vivax RON2, the disulfide bond between C2051 and C2063 in the cyclic form of the PvRON2 peptide is essential for interaction with PvAMA1; the linear peptide lacking this bond showed no detectable interaction by SPR or ITC, establishing that the RON2 disulfide-constrained structure is required for AMA1 binding. |
Surface plasmon resonance, isothermal titration calorimetry, far western blot, circular dichroism, SAXS |
Malaria journal |
High |
30683104
|
| 2017 |
Crystal structure of the complex formed between PvAMA1 and PvRON2sp1 peptide was determined. Binding studies showed PvRON2sp1 has strong cross-reactivity with PfAMA1, but PfRON2sp1 has no detectable interaction with PvAMA1; the species asymmetry was largely attributable to PvRON2-Thr2055 versus PfRON2-Arg2041. |
X-ray crystallography, surface plasmon resonance binding assays |
PloS one |
High |
28817634
|
| 2023 |
Specific residues in the β-hairpin loop of RON2 and specific residues in AMA1 Loop1E determine species-specific binding between AMA1 and RON2 in P. falciparum and P. vivax. Mutation of specific amino acids in AMA1 Loop1E in P. falciparum ablated RON2 binding without impacting erythrocyte invasion, demonstrating that the AMA1-RON2-loop interaction is NOT essential for invasion and that additional AMA1 interactions are involved. |
Site-directed mutagenesis of AMA1 and RON2, erythrocyte invasion assay, binding assays |
Cellular and molecular life sciences : CMLS |
High |
36847896
|