Analysis of phosphorylated proteins and inhibition of kinase activity during Giardia intestinalis excystation.
The parasite Giardia intestinalis undergoes a differentiation process that allows it to infect its mammal host. That process is excystation. We examined the importance of protein phosphorylation during the passage from cyst to trophozoite. Cysts obtained from patients with giardiasis were excysted in vitro and the soluble cytoplasmic proteins were analyzed during the three phases of the process, using a specific staining for phosphoproteins. We found two phosphorylated proteins and identified them with MALDI-TOF as 14-3-3 and Hsp70. Modifications were detected in both proteins, which could indicate a role in differentiation of the parasite. In addition, the inhibition of serine-threonine kinases during excystation specifically affected the cytokinesis of the excyzoite, thus inhibiting the completion of trophozoite formation.
Laboratorio de Investigaciones Básicas en Bioquímica, Departamento de Química, Universidad Nacional de Colombia, Bogotá calle 44 No 45-67 Bloque 10 nivel 4 Unidad Camilo Torres, Colombia.
Magda E
ME
Alvarado
Moisés
M
Wasserman
D048948:14-3-3 Proteins / Q000378:metabolism*; D000818:Animals; D016829:Giardia lamblia / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism; D005873:Giardiasis / Q000469:parasitology; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D015800:Protozoan Proteins / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053058:Trophozoites / Q000378:metabolism
D048948:14-3-3 Proteins; D018840:HSP70 Heat-Shock Proteins; D015800:Protozoan Proteins; D017346:Protein Serine-Threonine Kinases