GRA54

GRA54 is a dense granule protein of Toxoplasma gondii that localizes to the parasitophorous vacuole and physically associates with the effector-translocation component MYR1 (PMID:32075880). Beyond this interaction and localization, GRA54 has no established functional role: it was not required for GRA16 translocation or host c-Myc/cyclin E1 upregulation in the study that identified it, and no further mechanistic detail has been characterized in the available corpus (PMID:32075880).

1. 2020 Medium

   To map the machinery driving effector export across the parasitophorous vacuole membrane, the MYR1 interactome was defined, placing GRA54 within the MYR1-associated protein network at the PV.

   Evidence Affinity purification/co-immunoprecipitation of MYR1 with mass spectrometry identification and imaging-based localization in Toxoplasma gondii

   PMID:32075880

   Open questions at the time

   • GRA54 was not tested as required for GRA16 translocation or host c-Myc/cyclin E1 upregulation, unlike GRA44, GRA45, and MYR4
   • the MYR1 interaction was detected by affinity purification without reciprocal or direct binding validation
   • no molecular activity, substrate, or specific role in translocation established

• Whether GRA54 contributes functionally to MYR1-dependent effector translocation, and by what mechanism, remains unresolved.
• no functional or genetic test of GRA54 requirement for effector export
• no defined molecular activity
• no structural or interaction interface data