Affinage · Toxoplasma gondii

STX19

putative transmembrane protein · UniProt S8FF39

Annotated
2026-09-08
1 papers in source corpus 1 papers cited in narrative 2 extracted findings

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

In Toxoplasma gondii, STX19 (TgStx19) is a novel Qc-SNARE that resides in the endoplasmic reticulum and functions in vesicular trafficking through the secretory system (PMID:34340555). It acts as a binding partner of TgStx18, substituting for the canonical Use1 partner found in other eukaryotes (PMID:34340555). Conditional ablation of TgStx19 causes severe defects in the secretory system, establishing its functional requirement for ER-based trafficking (PMID:34340555). Beyond these findings, no further mechanistic detail on TgStx19 has been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 2 steps
  1. 2021 Medium

    It was unknown how the ER SNARE machinery is organized in Toxoplasma; imaging and conditional knockout established that TgStx19 is an ER-localized Qc-SNARE that partners with TgStx18 in place of the canonical Use1, defining a divergent SNARE architecture in this parasite.

    Evidence Fluorescence localization and conditional knockout with phenotypic analysis in Toxoplasma gondii

    PMID:34340555

    Open questions at the time
    • Direct biochemical demonstration of the TgStx19-TgStx18 SNARE complex and its full R-SNARE/Qa/Qb composition is not established
    • The specific trafficking step and cargoes dependent on TgStx19 are not defined
  2. 2021 Medium

    Whether TgStx19 is functionally required was unknown; conditional ablation producing severe secretory-system defects established that TgStx19 is necessary for vesicular trafficking through the ER.

    Evidence Conditional knockout with phenotypic analysis of secretory pathway defects in Toxoplasma gondii

    PMID:34340555

    Open questions at the time
    • The molecular basis linking loss of TgStx19 to the secretory defect (fusion failure, mislocalization of partners) is not resolved
    • Impact on parasite viability, invasion, or virulence is not delineated in this corpus

Open questions

Synthesis pass · forward-looking unresolved questions
  • The structural basis of TgStx19 SNARE-complex assembly, its complete set of interacting SNAREs, and the precise trafficking step it mediates remain undetermined.
  • No structural or reconstituted-fusion characterization of the TgStx19 complex
  • No mapping of the exact ER trafficking substep or cargo dependence

Mechanism profile

Synthesis pass · controlled-vocabulary classification
Partners
TGSTX18
Complex memberships
TgStx19-TgStx18 SNARE complex

Evidence

Reading pass · 2 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2021 TgStx19 is a novel Qc-SNARE localized to the endoplasmic reticulum (ER) in Toxoplasma gondii, where it acts as a binding partner of TgStx18, replacing the canonical Use1 partner found in other eukaryotes. Fluorescence localization experiments and conditional ablation (conditional knockout) with phenotypic analysis of secretory system defects mBio Medium 34340555
2021 Conditional ablation of TgStx19 (an ER-residing SNARE) caused severe defects in the secretory system, establishing its functional requirement for vesicular trafficking through the ER in Toxoplasma gondii. Conditional knockout with phenotypic analysis of secretory pathway defects mBio Medium 34340555

Source papers

Stage 0 corpus · 1 paper · ranked by NIH iCite citations
Year Title Journal Citations PMID
2021 The Dissection of SNAREs Reveals Key Factors for Vesicular Trafficking to the Endosome-like Compartment and Apicoplast via the Secretory System in Toxoplasma gondii. mBio 20 34340555