Biochemical Characterization of Branched Chain Amino Acids Uptake in Trypanosoma cruzi.
Trypanosoma cruzi is the etiological agent of Chagas disease. During its life cycle, it alternates among vertebrate and invertebrate hosts. Metabolic flexibility is a main biochemical characteristic of this parasite, which is able to obtain energy by oxidizing a variety of nutrients that can be transported from the extracellular medium. Moreover, several of these metabolites, more specifically amino acids, have a variety of functions beyond being sources of energy. Branched chain amino acids (BCAA), beyond their role in ATP production, are involved in sterol biosynthesis; for example, leucine is involved as a negative regulator of the parasite differentiation process occurring in the insect midgut. BCAA are essential metabolites in most nonphotosynthetic eukaryotes, including trypanosomes. In view of this, the metabolism of BCAA in T. cruzi depends mainly on their transport into the cell. In this work, we kinetically characterized the BCAA transport in T. cruzi epimastigotes. Our data point to BCAA as being transported by a single saturable transport system able to recognize leucine, isoleucine and valine. In view of this, we used leucine to further characterize this system. The transport increased linearly with temperature from 10 to 45 °C, allowing the calculation of an activation energy of 51.30 kJ/mol. Leucine uptake was an active process depending on ATP production and a H(+) gradient, but not on a Na(+) or K(+) gradient at the cytoplasmic membrane level.
LaBTryps, Instituto de Ciencias Biomedicas II, Universidade de São Paulo, Av. Lineu Prestes 1374, Cidade Universitária Butanta, São Paulo, CEP 05508-900, Brazil.
Nubia C
NC
Manchola
LaBTryps, Instituto de Ciencias Biomedicas II, Universidade de São Paulo, Av. Lineu Prestes 1374, Cidade Universitária Butanta, São Paulo, CEP 05508-900, Brazil.
Ludmila N
LN
Rapado
LaBTryps, Instituto de Ciencias Biomedicas II, Universidade de São Paulo, Av. Lineu Prestes 1374, Cidade Universitária Butanta, São Paulo, CEP 05508-900, Brazil.
María J
MJ
Barisón
LaBTryps, Instituto de Ciencias Biomedicas II, Universidade de São Paulo, Av. Lineu Prestes 1374, Cidade Universitária Butanta, São Paulo, CEP 05508-900, Brazil.
Ariel M
AM
Silber
D000255:Adenosine Triphosphate / Q000378:metabolism; D026905:Amino Acid Transport Systems; D000597:Amino Acids, Branched-Chain / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D014355:Chagas Disease / Q000469:parasitology; D007532:Isoleucine / Q000378:metabolism / Q000494:pharmacology; D007700:Kinetics; D007930:Leucine / Q000378:metabolism / Q000494:pharmacology; D013696:Temperature; D014349:Trypanosoma cruzi / Q000187:drug effects / Q000378:metabolism*; D014633:Valine / Q000378:metabolism / Q000494:pharmacology
D026905:Amino Acid Transport Systems; D000597:Amino Acids, Branched-Chain; D007532:Isoleucine; D000255:Adenosine Triphosphate; D007930:Leucine; D014633:Valine
Amino acid transport; Chagas disease; isoleucine; leucine; valine