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

BOUVIER, LEÓN ALBERTO; MIRANDA, MARIANA; CANEPA, GASPAR; PEREIRA, CLAUDIO

Caxambú, Brazil

Congreso; XXX Annual Meeting in Basic Research in Chagas Disease. XX, Annual Meeting of The Brazilian Society of Protozoology; 2004

Maintenance of cellular energy homeostasis is a crucial cellular process. Cellular energy transfer by difusional exchange of ATP is kinetically and thermodynamically ineficient 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 main taining energy balance are adenylate kinase (phosphotransferase with a phosphate group as acceptor) and arginine kinase (phosphotransferase with a nitrogenous group as accep tor). 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 by a comparative genomic analysis of the arginine kinase gene loci in different protozoan parasites. In order to analyse the role of these enzymes we determined the effect of silencing the expression of all three isoform genes in procyclic Trypanosoma brucei by RNA interference. Finally, we identified seven distinct adenylate kinases in Trypanosoma cruzi, more than reported for any other organism, and we characterized two of these isoforms.