ICMAP2

ICMAP2 is an intraconoidal microtubule-associated protein in Toxoplasma gondii required to maintain the integrity of the intraconoidal microtubules (ICMTs) and their attachment to the conoid (PMID:38191574). Conditional depletion of ICMAP2 causes the ICMTs to dissociate and detach from the conoid, with concomitant dispersion of microtubule-associated vesicles and rhoptries, establishing that ICMAP2 scaffolds the positioning of these organelles for sustained, iterative rhoptry discharge during invasion (PMID:38191574). Beyond this single loss-of-function characterization, no further molecular detail — including direct binding partners, structural basis of ICMT association, or biochemical activity — has been characterized in the available corpus.

1. 2024 High

   It was unknown what maintains intraconoidal microtubule cohesion and anchors them to the conoid; conditional depletion showed ICMAP2 is required for ICMT integrity and for scaffolding the positioning of microtubule-associated vesicles and rhoptries, establishing its role in enabling iterative rhoptry discharge.

   Evidence Conditional knockdown of ICMAP2 with ultrastructural and fluorescence imaging of ICMT organization, conoid attachment, and rhoptry/MV localization in Toxoplasma gondii

   PMID:38191574

   Open questions at the time

   • No direct binding partners or molecular basis of ICMAP2-ICMT association identified
   • No structural model of how ICMAP2 tethers ICMTs to the conoid
   • Mechanism linking ICMT integrity to rhoptry discharge not resolved biochemically

• The molecular partners, structural basis of microtubule binding, and biochemical activity of ICMAP2 remain undefined.
• No interactome or reciprocal binding validation for ICMAP2
• No domain-level or structural characterization
• No mechanism for how ICMAP2 loss propagates to rhoptry mispositioning