RPS2

TgRPS2 is a ribosomal protein S2 homolog of Toxoplasma gondii identified as a circulating antigen during acute infection (PMID:33537014). In RH-strain tachyzoites it localizes to the apical end and is secreted, being detectable in the serum of infected mice (PMID:33537014). Beyond this localization and its recognition as a circulating antigen (PMID:33537014), no molecular mechanism or functional role has been characterized in the available corpus.

1. 2021 Low

   Establishing where TgRPS2 resides in the parasite and whether it reaches host circulation addressed whether a ribosomal protein could serve as an accessible infection marker; the work showed apical localization and secretion into serum, establishing TgRPS2 as a circulating antigen of acute toxoplasmosis.

   Evidence Immunofluorescence for localization, immunoprecipitation-LC-MS/MS for antigen identification, and Western blotting for serum detection in T. gondii RH-infected mice

   PMID:33537014

   Open questions at the time

   • Single lab, localization by IFA without functional follow-up or reciprocal validation
   • No mechanistic pathway placement or defined molecular function beyond antigen recognition
   • Mechanism of apical targeting and secretion of a ribosomal protein is unresolved

• The molecular function of TgRPS2 beyond its identity as a secreted antigen, and how a ribosomal protein comes to localize apically and enter host circulation, remain unknown.
• No functional characterization or knockout phenotype
• No binding partners or pathway placement established
• Secretion mechanism uncharacterized