CLIP

CLIP (CLAMP-linked invasion protein) is a microneme protein of Toxoplasma gondii that acts in the host-cell invasion machinery by forming a distinct trimeric complex with CLAMP and SPATR (PMID:37886905). Conditional knockdown of CLIP disrupts rhoptry discharge following host-cell contact, establishing the complex as essential for invasion (PMID:37886905). Beyond its role in linking complex integrity to rhoptry exocytosis, no additional biochemical or structural mechanism for CLIP has been characterized in the available corpus.

1. 2023 High

   Whether an uncharacterized microneme factor coordinated with rhoptry discharge existed was unknown; identifying CLIP as an obligate partner of CLAMP and SPATR whose loss blocks rhoptry discharge established a defined complex required for invasion.

   Evidence Reciprocal co-immunoprecipitation/complex identification with conditional knockdown scored by a rhoptry discharge assay in Toxoplasma gondii

   PMID:37886905

   Open questions at the time

   • Stoichiometry, architecture, and direct binding interfaces of the CLIP-CLAMP-SPATR complex not resolved
   • Molecular step by which the complex triggers or licenses rhoptry discharge not defined
   • Individual contribution of CLIP versus CLAMP and SPATR not separately dissected