INVESTIGADORES
ANGEL Sergio Oscar
congresos y reuniones científicas
Título:
Characterization of Hip and P23 Toxoplasma gondii Hsp90 co-chaperones
Autor/es:
PABLO CRISTIAN ECHEVERRIA; MARIA JULIA LOPEZ; NATALIA DE MIGUEL; MARIANA MATRAJT; JEAN F. DUBREMETZ; SERGIO OSCAR ANGEL
Lugar:
Montana Estados Unidos
Reunión:
Congreso; 9th International Congress on Toxoplasmosis; 2007
Institución organizadora:
Congress on Toxoplasmosis
Resumen:
Toxoplasma gondii is among the most successful parasites, with nearly half of the human population chronically infected. Asexual replication of T. gondii in humans and intermediate hosts is characterized by two stages: rapidly growing ‘tachyzoites’ and latent ‘bradyzoite’ tissue cysts. Recently a link between nuclear localization of T. gondii Hsp90 and parasite development was observed. The stage conversion was blocked using Hsp90 inhibitors as geldanamycin, highlighting the role of Hsp90 in parasite development. Hip is an Hsp70 interacting co-chaperone that is also found in early Hsp90-heterocomplexes. P23 is an Hsp90 co-chaperone, which is associated to mature Hsp90-heterocomplex. Toxoplasma gondii P23 and Hip were identified by searching the Toxoplasma- database (www.toxodb.org). Their identity was confirmed by domain structure and blast analysis. Antibodies against these co-chaperones were obtained by immunization with recombinant Hip and P23 proteins. Complex formation was studied by co-immunoprecipitation analysis (co-IP). Studies of co-immunoprecipitation identified a complex comprising at least Hip-Hsp70-Hsp90 and another complex comprising at least P23-Hsp90. The subcellular localization in intracellular PK (cystogenic strain) parasites grown in tachyzoites and bradyzoites conditions in vitro was examined by indirect immunofluorescence assay. Hip showed a cytoplasmic subcellular localization both in tachyzoites and bradyzoites. Concerning P23, a cytoplasmic localization was observed in tachyzoite stage whereas both, nuclear and cytosolic labeling were found in bradyzoites, colocalizing with the Hsp90. These results suggest that the T. gondii Hsp90-heterocomplex cycle is similar to what is proposed for higher eukaryotes, and that Hsp90-heterocomplex components could be implicated in parasite development.