Aurora kinase family in Trypanosoma cruzi.

ALONSO, G.D.; BIRNBAUMER, L; FLAWIÁ, M.M.; TORRES, H.N.

Rosario. Santa Fe, Argentina.

Congreso; XLII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular.; 2006

SAIB

The chromosomal passenger protein aurora kinases have been implicated in regulating chromosome segregation and cell division. Three chromosome passenger proteins, aurora A, B, and C, were identified in mammals. Consistent with their localizations, aurora A regulates spindle assembly, aurora B controls chromosome segregation and cytokinesis initiation and aurora C was found in testis and certain tumor cell lines and localized to spindle poles during late mitosis. This work describes three aurora kinase homologues (TcAUK1, 2 and 3) in Trypanosoma cruzi. The protein products were obtained by expression in E. coli and evaluated for enzymatic activity by using H2AS Histone mix from Sigma, and Myelin Basic Protein as substrates. It is know that human aurora-B is phosphorylated at Thr-232 through interaction with the inner centromere protein (INCENP) in vivo. The phosphorylation of Thr-232 occurs by means of an autophosphorylation mechanism, which is indispensable for the aurora-B kinase activity. According to this observation we explored the TcAUKs looking for the modification site and interestingly the phosphorylable Thr was present in all of them. To study the effect of the putative phosphorylation we changed Thr x (Asp or Glu) by site-direct mutagenesis and expressed the mutated enzymes in E. coli. In addition we expressed TcAUK1 in mammalian cells and kinase activity was measured.