Affinage · Toxoplasma gondii

ISC4

IMC sutures component ISC4 · UniProt A0A125YFD7

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

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

ISC4 is a component of the inner membrane complex (IMC) sutures of Toxoplasma gondii, localizing to both the transverse and longitudinal sutures (PMID:27696623). Deployed as a BioID bait, ISC4 defined the suture proteome, driving identification of two additional ISC proteins and five transverse suture-specific proteins (TSCs) (PMID:27696623). Beyond this structural suture occupancy, no molecular function for ISC4 has been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 1 step
  1. 2016 Medium

    Establishing where an uncharacterized IMC-associated protein resides and what it neighbors was needed to place it in the parasite cytoskeletal architecture; using ISC4 as a BioID bait localized it to both transverse and longitudinal sutures and mapped its proximal proteome.

    Evidence Proximity-dependent biotin identification (BioID) with ISC4 as bait plus fluorescence microscopy validation in Toxoplasma gondii

    PMID:27696623

    Open questions at the time
    • The molecular function of ISC4 beyond structural suture occupancy is not established
    • Whether ISC4 is required for suture integrity, parasite viability, or division is not tested
    • Direct binding partners versus mere proximity-labeled neighbors are not distinguished

Open questions

Synthesis pass · forward-looking unresolved questions
  • The biochemical activity of ISC4 and its functional contribution to suture assembly or parasite fitness remain unknown.
  • No enzymatic or structural activity assigned
  • No loss-of-function phenotype characterized
  • No direct interaction partners validated

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
FIVE TRANSVERSE SUTURE-SPECIFIC PROTEINS (TSCS, BIOID-PROXIMAL)TWO ISC PROTEINS (BIOID-PROXIMAL)

Evidence

Reading pass · 1 per-paper finding extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2016 ISC4 was used as bait for proximity-dependent biotin identification (BioID) at the IMC sutures, demonstrating biotin-dependent labeling of the sutures and identifying two new ISC proteins and five transverse suture-specific proteins (TSCs), establishing ISC4 as a component of the IMC sutures that localizes to both transverse and longitudinal sutures. Proximity-dependent biotin identification (BioID) using ISC4 as bait, followed by fluorescence microscopy validation Cellular microbiology Medium 27696623

Source papers

Stage 0 corpus · 9 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2016 Novel insights into the composition and function of the Toxoplasma IMC sutures. Cellular microbiology 59 27696623
2016 Virus-Like Nanoparticle Vaccine Confers Protection against Toxoplasma gondii. PloS one 33 27548677
2011 Subcellular antigen location influences T-cell activation during acute infection with Toxoplasma gondii. PloS one 33 21829561
2014 Identification and characterization of Toxoplasma SIP, a conserved apicomplexan cytoskeleton protein involved in maintaining the shape, motility and virulence of the parasite. Cellular microbiology 28 25088010
2016 Cross-protection induced by Toxoplasma gondii virus-like particle vaccine upon intraperitoneal route challenge. Acta tropica 15 27586039
2021 A Novel Toxoplasma Inner Membrane Complex Suture-Associated Protein Regulates Suture Protein Targeting and Colocalizes with Membrane Trafficking Machinery. mBio 12 34634933
2025 Co-dependent formation of the Toxoplasma gondii subpellicular microtubules and inner membrane skeleton. mBio 11 40801525
2009 Toxoplasma gondii: further studies on the subpellicular network. Memorias do Instituto Oswaldo Cruz 11 19820829
2024 Apical annuli are specialised sites of post-invasion secretion of dense granules in Toxoplasma. eLife 10 38270431