A NEW MEMBER OF YER057C FAMILY IN TRYPANOSOMA-CRUZI IS ADJACENT TO ANABC-TRANSPORTER

Tcp17 is a Trypanosoma cruzi gene located contiguous to the ABC-transp orter tcpgp2. The protein contains 160 amino acid residues with a pred icted molecular mass of 16.5 kDa. Western blot analysis using a polycl onal antiserum against recombinant TCP17 revealed that the protein is only expressed in the epimastigote form of the parasite; we did not de tect the protein either in the amastigote or trypomastigote forms. A s equence comparison of TCP17 showed a remarkable homology with a conser ved family of prokaryotic and eukaryotic proteins called YER057c whose function has not yet been characterized. Here, we propose a new signa ture of this family considering the N-terminal: [IV]-X(4)-[AV]-[AP]-X- [AP]-X(3)-Y-X(9)-[LIVF]-X (2)-[SA]-G-[QS], and the C-terminal: 2)-[IVF Y]-X-[VC]-X(2)-L-P-X(4)-[LIVM]-E-[IVM]-[DE] motifs. Immunofluorescence and immunoelectron microscopy studies suggest that the protein has a wide distribution in the cell, with a higher concentration in the exte rnal side of the plasma membrane, on the Golgi complex and on cytoplas mic vacuoles. Although the physiological function of TCP17 is unknown, its conservation in evolution suggests biological relevance in the pa rasite. (C) 1998 Elsevier Science B.V. All rights reserved.