THE INTERACTION MAP OF TRYPANOSOMA CRUZI RIBOSOMAL P PROTEIN COMPLEX

SIMONETTI L., SMULSKI C.R., LONGHI S.A., JURI AYUB M., BASILE J.N., HOEBEKE J., LEVIN M.J.

Aguas de Lindóia- SP- Brazil

Congreso; XXXV Annual Meeting on Basic Research in Chagas´Disease, XXIV Annual Meeting of the Brazilian Society of Protozoology; 2008

Sociedad Brasileña de Protozoología

The ribosomal P proteins are located on the stalk of the ribosomal large subunit and play a critical role during the elongation step of protein synthesis through interaction with elongation factor 2 (EF2). The stalk, in Trypanosoma cruzi, is composed by four proteins of about 11 KDa, TcP1a, TcP1b, TcP2a, TcP2b and a fifth TcP0 of about 30 KDa. In order to study the ribosomal P protein complex assembly, a yeast two-hybrid interaction map was generated that indicated a central role for TcP0. Using Surface Plasmon Resonance the kinetics of each interaction between the members of this protein family and with the EF2 were analyzed. The assembly of ternary complexes was also assessed and the interaction domains of TcP0 and TcP2b were mapped using truncated proteins and synthetic peptides, respectively. Results showed that TcP0 and TcP2b proteins were able to form homo dimers and also interacted with both P1 and both P2 proteins. All ribosomal P proteins interact with EF2, but the small P proteins showed a stronger affinity than TcP0. The C-terminal region of TcP2b (peptide R15) seems to be involved in the interaction with EF2, since R15 was able to inhibit the second step of the association phase. Other regions of the protein may also be involved because R15 had no effect on the first step of the association phase. Compared to other species, T. cruzi displays a specific pattern of ribosomal P protein interactions that could be targeted by selective therapeutic agents