IMC24

IMC24 is a cytoskeletal component of the inner membrane complex (IMC) of Toxoplasma gondii, contributing to the structural organization of the parasite pellicle (PMID:25691595). It was first identified by BioID proximity labeling as a novel IMC protein localizing to the alveolar/cytoskeletal network subcompartment (PMID:25691595). Mechanistically, IMC24 directly binds IMT1, a bridging protein that tethers the IMC cytoskeleton to the underlying subpellicular microtubules, placing IMC24 at the interface between these two structural elements of the pellicle (PMID:40768331). Beyond this tethering interaction, no further functional detail for IMC24 has been characterized in the available corpus.

1. 2015 Medium

   Establishing which proteins constitute the Toxoplasma IMC was needed to define the parasite's cytoskeletal architecture; IMC24 was newly assigned to the IMC as a component of the alveolar/cytoskeletal network.

   Evidence BioID proximity-dependent biotin identification in T. gondii

   PMID:25691595

   Open questions at the time

   • No individual functional characterization of IMC24 was performed
   • The precise binding partners and molecular role were not defined
   • Contribution to parasite viability or morphology not tested
2. 2025 Medium

   How the IMC cytoskeleton connects to subpellicular microtubules was unresolved; IMC24 was shown to directly bind the tethering protein IMT1, positioning it at the IMC–microtubule interface.

   Evidence Reciprocal BioID of IMT1 interactors combined with deletion and mutagenesis analyses in T. gondii, identifying IMC24 as a direct IMT1 binding partner alongside IMC1 and IMC18

   PMID:40768331

   Open questions at the time

   • The binding interface/domain of IMC24 mediating IMT1 contact is not mapped
   • The functional consequence of disrupting the IMC24–IMT1 interaction is not established
   • Single-lab study without independent reciprocal validation of the direct binding

• The functional requirement of IMC24 for pellicle integrity, parasite replication, and its structural mechanism at the IMC–microtubule interface remain to be determined.
• No loss-of-function phenotype for IMC24 reported
• No structural model of IMC24 or its IMT1-binding region
• Timing of IMC24 recruitment during pellicle biogenesis is unknown