The glutamine synthetase of Trypanosoma cruzi is required for its resistance to ammonium accumulation and evasion of the parasitophorous vacuole during host-cell infection

Author(s):Show less -

Crispim, Marcell ^[1] ; Damasceno, Flavia Silva ^[1] ; Hernandez, Agustino ^[1] ; Barison, Maria Julia ^[1] ; Sauter, Ismael Pretto ^[2] ; Pavani, Raphael Souza ^[3] ; Moura, Alexandre Santos ^[1] ; Furusho Pral, Elizabeth Mieko ^[1] ; Cortez, Mauro ^[2] ; Elias, Maria Carolina ^[3] ; Silber, Ariel Mariano ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Parasitol, Lab Biochem Tryps LaBTryps, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Biomed Sci, Dept Parasitol, Immunobiol Leishmania Macrophage Interact Lab, Sao Paulo - Brazil

^[3] Butantan Inst, Ctr Toxins Immunol & Cell Signalling, Special Lab Cell Cycle, Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: PLoS Neglected Tropical Diseases; v. 12, n. 1 JAN 2018.
• Web of Science Citations: 5

Abstract

Trypanosoma cruzi, the etiological agent of Chagas disease, consumes glucose and amino acids depending on the environmental availability of each nutrient during its complex life cycle. For example, amino acids are the major energy and carbon sources in the intracellular stages of the T. cruzi parasite, but their consumption produces an accumulation of NH4+ in the environment, which is toxic. These parasites do not have a functional urea cycle to secrete excess nitrogen as low-toxicity waste. Glutamine synthetase (GS) plays a central role in regulating the carbon/nitrogen balance in the metabolism of most living organisms. We show here that the gene TcGS from T. cruzi encodes a functional glutamine synthetase; it can complement a defect in the GLN1 gene from Saccharomyces cerevisiae and utilizes ATP, glutamate and ammonium to yield glutamine in vitro. Overall, its kinetic characteristics are similar to other eukaryotic enzymes, and it is dependent on divalent cations. Its cytosolic/ mitochondrial localization was confirmed by immunofluorescence. Inhibition by Methionine sulfoximine revealed that GS activity is indispensable under excess ammonium conditions. Coincidently, its expression levels are maximal in the amastigote stage of the life cycle, when amino acids are preferably consumed, and NH4+ production is predictable. During host-cell invasion, TcGS is required for the parasite to escape from the parasitophorous vacuole, a process sine qua non for the parasite to replicate and establish infection in host cells. These results are the first to establish a link between the activity of a metabolic enzyme and the ability of a parasite to reach its intracellular niche to replicate and establish host-cell infection. (AU)

• FAPESP's process: 13/07467-1 - CeTICS - Center of Toxins, Immune-Response and Cell Signaling
• Grantee: Hugo Aguirre Armelin
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 16/06034-2 - The biological role of amino acids and their metabolites in Trypanosoma cruzi
• Grantee: Ariel Mariano Silber
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 15/10580-0 - Characterization of intra-S checkpoint in Trypanosoma cells
• Grantee: Maria Carolina Quartim Barbosa Elias Sabbaga
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/10443-0 - Mechanisms and consequences of intracellular traffic impairment by 8- and 14-dehydrosterols in fungal parasite models
• Grantee: Agustín Hernández López
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 16/50050-2 - How do common and diverged features of the replicative stress response shape the biology of TriTryp parasites?
• Grantee: Maria Carolina Quartim Barbosa Elias Sabbaga
• Support Opportunities: Research Projects - Thematic Grants