Affinage · Toxoplasma gondii

IMC18

inner membrane complex protein IMC18 · UniProt A0A125YNR8

Annotated
2026-09-08
2 papers in source corpus 2 papers cited in narrative 2 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

IMC18 is a cytoskeletal component of the Toxoplasma gondii inner membrane complex (IMC) (PMID:25691595). It contributes to the structural linkage between the IMC cytoskeleton and the underlying subpellicular microtubules by directly binding the microtubule-tethering protein IMT1, positioning IMC18 within a protein bridge that connects the two cytoskeletal systems (PMID:40768331). Beyond its identification as an IMC network component and its direct interaction with IMT1, no further mechanistic detail has been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 2 steps
  1. 2015 Medium

    Establishing which proteins make up the IMC cytoskeletal network was needed to map the pellicle architecture; BioID from known IMC baits identified IMC18 as a novel resident of this compartment.

    Evidence Proximity-dependent biotin identification (BioID) with known IMC proteins as bait plus localization studies in T. gondii

    PMID:25691595

    Open questions at the time
    • Single lab, single-method identification for IMC18 specifically
    • No functional role or binding partners defined at this stage
    • No knockout/phenotype data
  2. 2025 Medium

    Whether IMC18 physically couples the IMC to the subpellicular microtubules was unresolved; deletion and mutagenesis analyses showed it binds the microtubule-tethering protein IMT1 directly, placing it in a bridge between the IMC cytoskeleton and the SPMTs.

    Evidence Proximity labeling, deletion analyses, mutagenesis and direct binding assays in T. gondii

    PMID:40768331

    Open questions at the time
    • Single lab characterization of the IMC18–IMT1 interaction
    • Functional consequence of disrupting the bridge for parasite morphology or motility not established here
    • Structural basis of the direct binding not resolved

Open questions

Synthesis pass · forward-looking unresolved questions
  • The functional requirement of IMC18 for pellicle integrity, cell division, or parasite viability, and the structural details of the IMC18–IMT1 bridge, remain unknown.
  • No loss-of-function phenotype reported
  • No structural model of the IMC18–IMT1 interface
  • Broader interactome of IMC18 within the IMC not defined

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
IMT1
Complex memberships
IMC-to-microtubule bridging complex (IMC18–IMT1)

Evidence

Reading pass · 2 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2015 IMC18 was identified as a novel component of the Toxoplasma inner membrane complex (IMC) cytoskeletal network using proximity-dependent biotin identification (BioID) with known IMC proteins as bait, localizing it to the IMC suborganellar compartment. BioID (proximity-dependent biotin identification) in T. gondii, followed by localization studies mBio Medium 25691595
2025 IMC18 directly binds the microtubule-tethering protein IMT1, as demonstrated by deletion analyses and mutagenesis, placing IMC18 as part of a protein bridge connecting the IMC cytoskeleton to the subpellicular microtubules (SPMTs). Proximity labeling, deletion analyses, mutagenesis, direct binding assays (Co-IP/pulldown implied by 'binds directly') Molecular biology of the cell Medium 40768331

Source papers

Stage 0 corpus · 2 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2015 Novel components of the Toxoplasma inner membrane complex revealed by BioID. mBio 148 25691595
2025 Function and interactions of a protein bridge between the inner membrane complex and subpellicular microtubules in Toxoplasma gondii. Molecular biology of the cell 2 40768331