title: Trypanosoma cruzi: in vitro phosphorylation of tubulin by a protein kinase CK2-like enzyme.
abstract: One predominant 55-kDa polypeptide was phosphorylated in vitro in Trypanosoma cruzi homogenates prepared from three differentiation stages: epimastigotes, trypomastigotes, and spheromastigotes. Anti-alpha and anti-beta tubulin monoclonal antibodies immunoprecipitated the phosphorylated 55-kDa polypeptide from epimastigote extracts. Phosphoserine was the only residue phosphorylated in vitro in the 55-kDa polypeptide and in immunoprecipitated alpha tubulin. The phosphorylation of both the 55-kDa polypeptide and exogenously added casein was inhibited with GTP, heparin, and 2,3-bisphosphoglycerate in a dose-dependent manner, indicating the involvement of a CK2-like protein kinase. Moreover, when tubulin was isolated from an epimastigote homogenate by ultracentrifugation, followed by DEAE-Sephacel chromatography, a protein kinase that phosphorylated tubulin and casein co-purified with this cytoskeletal component. This result suggests an association between tubulin and its corresponding protein kinase in T. cruzi.
authors.affiliation: Departamento de Biología Celular, Universidad Simón Bolívar, Apartado 89.000, Caracas, Venezuela.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Casas
authors.forename: Maritza
authors.initials: M
authors.lastname: Calabokis
authors.forename: Liliana
authors.initials: L
authors.lastname: Kurz
authors.forename: José M
authors.initials: JM
authors.lastname: Galán-Caridad
authors.forename: José
authors.initials: J
authors.lastname: Bubis
authors.forename: Mary I
authors.initials: MI
authors.lastname: Gonzatti
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015153:Blotting, Western; D047390:Casein Kinase II; D002522:Chlorocebus aethiops; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D010766:Phosphorylation; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D015800:Protozoan Proteins / Q000378:metabolism; D014349:Trypanosoma cruzi / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D014404:Tubulin / Q000276:immunology / Q000378:metabolism*; D014709:Vero Cells
chemical_list: D000911:Antibodies, Monoclonal; D015800:Protozoan Proteins; D014404:Tubulin; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases