Post genomic analysis of adenylate and arginine kinases: phosphotransfer processes in Trypanosomes.

MIRANDA, MARIANA; BOUVIER, LEON; CANEPA, GASPAR; PEREIRA, CA

Caxambu

Congreso; XX Annual Meeting of The Brazilian; 2004

Maintenance of cellular energy homeostasis is a crucial cellular process. Cellular energy transfer by diffusional exchange of ATP is kinetically and thermodynamically inefficient since it requires a significant 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 buffer 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, a comparative genomic analysis of the arginine kinase gene loci in different protozoan parasites. The effect of silencing the expression of all three isoform genes in procyclic Trypanosoma brucei by RNA interference in order to analyse the role of these enzymes in vivo. At last, the identification of seven distinct adenylate kinases in Trypanosoma cruzi, more than reported for any other organism, and the characterization of two of these isoforms.