These typical cytosolic patterns clearly differed from those corresponding to mitochondrial proteins

(Fig. 2a–c and g–i). By contrast, TbME1 and TcME1 showed a fluorescence pattern canonically assigned to a mitochondrial localization. The green signal corresponding to the primary antibody perfectly colocalized with the red signal corresponding to the organelle-specific marker, Mitotracker™, rendering the expected yellow fluorescence when both images were superimposed selleck chemicals llc (Fig. 2d–f and j–l). Our findings showed that in T. brucei and T. cruzi the cytosolic and mitochondrial isozymes are expressed throughout the life cycle of both pathogens (Fig. 3). However, in T. brucei, both MEs appeared to be more abundant in the insect stage (Fig. 3a). By contrast, in T. cruzi the mitochondrial ME seemed to be more abundant in the intracellular amastigotes, and the highest expression levels of the cytosolic isoform were immunodetected in the metacyclic selleckchem trypomastigotes (Fig. 3b). In mammals,

MEs are represented by three isoforms, the cytosolic and mitochondrial NADP-dependent enzymes, and the mitochondrial NAD-linked isozyme. The former enzymes, together with glucose 6-phosphate dehydrogenase, have attracted much attention because they play essential roles in lipogenesis by providing the reduced coenzyme. The results we report herein demonstrate that, unlike the mammalian MEs, the trypanosomal isozymes are exclusively specific for NADP+. The N-terminal extension of TbME1 (Tb11.02.3130), TcME1a (Tc00.1047053505183.20) and TcME1b (Tc00.1047053508647.270) could represent Alanine-glyoxylate transaminase the mitochondrial targeting sequence for these enzymes. Accordingly, our subcellular localization studies confirmed that TbME1 and TcME1 (Tb11.02.3130 and Tc00.1047053505183.20) encoded functional mitochondrial

isoforms, whereas TbME2 and TcME2 (Tb11.02.3120 and Tc00.1047053508647.280) corresponded to the cytosolic isozymes. Although the MEs from trypanosomes share similar but not identical kinetic properties, they have equivalent catalytic efficiencies for the generation of NADPH. The major distinguishing kinetic feature is the particularly high Km value of the T. cruzi cytosolic isozyme towards malate (5–10-fold) and its remarkable allosteric activation by l-aspartate. The expression of MEs is developmentally regulated in T. cruzi and T. brucei. In these pathogens, the MEs may play pivotal roles in those stages that have adapted to grow in environments where glucose is very low or absent, and the production of NADPH through pentose phosphate pathway is arrested. This is particularly the case with T. cruzi amastigotes, which are unable to uptake glucose because the expression of hexose transporters is notably repressed in this intracellular stage. Therefore, these forms are expected to depend on amino acids to sustain their essential metabolic processes (Silber et al., 2009). The insect stage of T. brucei, but not that of T.