The Uptake of GABA in Trypanosoma cruzi

Author(s)

Galvez Rojas, Robert L. ^[1] ; Ahn, Il-Young ^[1] ; Mantilla, Brian Suarez ^[1] ; Sant'Anna, Celso ^[2] ; Furusho Pral, Elizabeth Mieko ^[1] ; Silber, Ariel Mariano ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Parasitol, BR-05508900 Sao Paulo, SP - Brazil

^[2] Inst Nacl Metrol INMetro, Rio De Janeiro - Brazil

• Document type: Journal article
• Source: Journal of Eukaryotic Microbiology; v. 62, n. 5, p. 629-636, SEP-OCT 2015.
• Web of Science Citations: 5

Abstract

Gamma aminobutyric acid (GABA) is widely known as a neurotransmitter and signal transduction molecule found in vertebrates, plants, and some protozoan organisms. However, the presence of GABA and its role in trypanosomatids is unknown. Here, we report the presence of intracellular GABA and the biochemical characterization of its uptake in Trypanosoma cruzi, the etiological agent of Chagas' disease. Kinetic parameters indicated that GABA is taken up by a single transport system in pathogenic and nonpathogenic forms. Temperature dependence assays showed a profile similar to glutamate transport, but the effect of extracellular cations Na+, K+, and H+ on GABA uptake differed, suggesting a different uptake mechanism. In contrast to reports for other amino acid transporters in T. cruzi, GABA uptake was Na+ dependent and increased with pH, with a maximum activity at pH 8.5. The sensitivity to oligomycin showed that GABA uptake is dependent on ATP synthesis. These data point to a secondary active Na+/GABA symporter energized by Na+-exporting ATPase. Finally, we show that GABA occurs in the parasite's cytoplasm under normal culture conditions, indicating that it is regularly taken up from the culture medium or synthesized through an still undescribed metabolic pathway. (AU)

• FAPESP's process: 13/18970-6 - Characterization of the Disulfiram effect in Trypanosoma cruzi
• Grantee: Ariel Mariano Silber
• Support Opportunities: Regular Research Grants