Post genomic análisis of adenylate and arginine kinases: phosphotransference processes in Trypanosomes

BOUVIER LA; MIRANDA MR; CANEPA GE; PEREIRA CA

Caxambu, Brasil

Congreso; XX Annual Meeting of the Brazilian Society of Protozoology, XXXI Annual Meeting on Basic Research in Chagas` Disease; 2004

Maintenance of cellular energy homeostasis is a crucial cellular process. Cellular energy transfer by di®usional exchangeof ATP is kinetically and thermodynamically ine±cient since it requires a signicant concentration gradient. In this work we propose the existence in Trypanosoma cruzi, of an enzymatic ´phosphotransfer network´ that communicates the spatially separated intracellular ATP consumption and production processes. Two enzymes with core roles in maintaining energy balance are adenylate kinase (phosphotransferase with a phosphate group as acceptor) and arginine kinase (phosphotransferase with a nitrogenous group as acceptor). Arginine kinase activity provides a spatial and temporal energy bu®er that can be readily mobilized during cellular stress. Adenylate kinase is involved in the homeostasis of adenine nucleotides by interconversion of constituents of the adenine nucleotide pool, including ATP synthesis from ADP. Here, we discuss the biological function of arginine kinase in Trypanosoma cruzi by a comparative genomic analysis of the arginine kinase gene loci in di®erent protozoan parasites. In order to analyse the role of these enzymes we determined the e®ect of silencing the expression of all three isoform genes in procyclic Trypanosoma brucei by RNA interference. Finally, we identied seven distinct adenylate kinases in Trypanosoma cruzi, more than reported for any other organism, and we characterized two of these isoforms.