Affinage · Toxoplasma gondii

AAP3

apical annuli protein AAP3 · UniProt S8ERD7

Annotated
2026-09-10
1 papers in source corpus 1 papers cited in narrative 3 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

AAP3 is a component of the apical annuli of Toxoplasma gondii, structures embedded within the sutures of the inner membrane complex (IMC), where it resides together with AAP1, AAP2, AAP4, AAP5, Centrin2, and an apical annuli methyltransferase as identified by reciprocal proximity biotinylation (BioID) and validated by super-resolution microscopy (PMID:31470470). Within this compartment, the apical annuli complex is organized as a concentric four-ring, pore-like structure of 200–400 nm diameter (PMID:31470470). Beyond its identification as an apical annuli complex member and its localization, no further mechanistic detail about AAP3 has been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 3 steps
  1. 2019 Medium

    Establishing that the apical annuli of Toxoplasma have a defined protein composition answered what molecules build these IMC-suture structures, placing AAP3 within a discrete multi-protein complex.

    Evidence Reciprocal BioID proximity biotinylation proteome mapping with super-resolution microscopy validation in Toxoplasma gondii

    PMID:31470470

    Open questions at the time
    • No mutagenesis or knockout to establish AAP3's functional role
    • Direct binding partners of AAP3 within the complex not resolved
    • No in vitro reconstitution of the complex
  2. 2019 Medium

    Super-resolution imaging resolved the architecture of the AAP3-containing apical annuli as a concentric four-ring pore-like structure, defining its spatial organization.

    Evidence Super-resolution microscopy of Toxoplasma gondii apical annuli

    PMID:31470470

    Open questions at the time
    • Position of AAP3 within the four-ring architecture not resolved
    • Functional consequence of the ring geometry unknown
  3. 2019 Low

    Comparative and domain analysis linked AAPs, including AAP3, to centrosomal-type coiled-coil/signalling domains and to coccidian parasites replicating by internal budding, hinting at a role tied to that replication mode.

    Evidence Phylogenetic and domain signature analysis of the apical annuli proteins

    PMID:31470470

    Open questions at the time
    • Inference is computational only, with no direct functional experiment for AAP3
    • The proposed link to internal budding replication is untested
    • Signalling activity of the predicted domains not demonstrated

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
AAP1AAP2AAP4AAP5APICAL ANNULI METHYLTRANSFERASECENTRIN2
Complex memberships
Apical annuli complex (AAP1, AAP2, AAP3, AAP4, AAP5, Centrin2, apical annuli methyltransferase)

Evidence

Reading pass · 3 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2019 AAP3 (along with AAP1, AAP2, AAP4, AAP5, Centrin2, and an apical annuli methyltransferase) was identified as a component of the apical annuli of Toxoplasma gondii, structures embedded within the inner membrane complex (IMC) sutures, validated by reciprocal proximity biotinylation (BioID). Reciprocal BioID proximity biotinylation proteome mapping; super-resolution microscopy Cellular microbiology Medium 31470470
2019 The apical annuli complex, of which AAP3 is a member, is organized in a concentric four-ring structure with diameters ranging from 200 to 400 nm, as revealed by super-resolution microscopy. Super-resolution microscopy Cellular microbiology Medium 31470470
2019 AAP3, as part of the apical annuli proteins, carries domain signatures shared with centrosomal proteins (coiled-coil and signalling domains), and phylogenetic analysis showed that the AAPs are conserved narrowly in coccidian apicomplexan parasites that multiply by internal budding, suggesting a role linked to internal budding replication. Phylogenetic analysis; domain signature analysis Cellular microbiology Low 31470470

Source papers

Stage 0 corpus · 1 paper · ranked by NIH iCite citations
Year Title Journal Citations PMID
2019 The apical annuli of Toxoplasma gondii are composed of coiled-coil and signalling proteins embedded in the inner membrane complex sutures. Cellular microbiology 38 31470470