Bromodomain factor 1 of Trypanosoma cruzi is localized in the glycosomes, targeted by an N-terminal sequence

CARLA RITAGLIATI; GABRIELA VANINA VILLANOVA; VICTORIA LUCIA ALONSO; PAMELA CRIBB; ESTEBAN SERRA

Mendoza

Congreso; XLVIII Reunion Anual de la Sociedad Argentina de Investigaciones en Bioquimica y Biologia Molecular; 2012

The bromodomain is the only known protein domain involved in the recognition of acetylated lysines. Acetylation is an ubiquitous and abundant posttranslational modification. Widespread acetylation of metabolic enzymes suggests a modification that is as important as protein phosphorylation in controlling cell function. TcBDF1 contains a bromodomain in its N-terminal half. WB analysis of T. cruzi lysates with antiTcBDF1, immunofluorescence microscopy of the different life cycle stages and immunoelectron microscopy of epimastigotes confirm TcBDF1´s non-nuclear localization. Colocalization assays with several markers suggest a glicosomal location. The amino acids sequence of TcBDF1 was analyzed with the PeroxisomeDB server, which recognized in its N-terminus a peroxisome-targeting signal type 2, one of the signals that direct glycosomal proteins into the matrix. To determine if the first 27 amino acids present in TcBDF1 are responsible of its import to the glycosome, we transiently transfected epimastigotes with constructs coding the whole protein, a truncated version which lacks the first 27 amino acids or only the N-terminus targeting signal, fused to the Red Fluorescent Protein. The intracellular localization of the different fusion proteins was determined by fluorescence microscopy. Our results confirm that BDF1 possesses a PTS2, responsible of directing the protein to the glycosomes