Please use this identifier to cite or link to this item: https://www.arca.fiocruz.br/handle/icict/13532
Title: Identification and functional characterization of a novel arginine/ornithine transporter, a member of a cationic amino acid transporter subfamily in the Trypanosoma cruzi genome
Authors: Henriques, Cristina
Miller, Megan P.
Catanho, Marcos
Carvalho, Técia Maria Ulisses de
Krieger, Marco Aurélio
Probst, Christian M.
Souza, Wanderley de
Degrave, Wim
Amara, Susan Gaye
Affilliation: Fundação Oswaldo Cruz. Campo Grande, MS, Brasil / Universidade Federal do Rio de Janeiro. Centro de Ciências da Saúde. Instituto de Biofísica Carlos Chagas Filho. Laboratório de Ultraestrutura Celular Hertha Meyer. Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. CENABIO. Núcleo de Biologia Estrutural e Bioimagem. Rio de Janeiro, RJ, Brasil.
University of Pittsburgh. School of Medicine. Department of Neurobiology. Pittsburgh, PA, USA.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Genômica Funcional e Bioinformática. Rio de Janeiro, RJ, Brasil.
Universidade Federal do Rio de Janeiro. Centro de Ciências da Saúde. Instituto de Biofísica Carlos Chagas Filho. Laboratório de Ultraestrutura Celular Hertha Meyer. Rio de Janeiro, RJ, Brasil
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.
Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.
Universidade Federal do Rio de Janeiro. Centro de Ciências da Saúde. Instituto de Biofísica Carlos Chagas Filho. Laboratório de Ultraestrutura Celular Hertha Meyer. Rio de Janeiro, RJ, Brasil / Universidade Federal do Rio de Janeiro. CENABIO. Núcleo de Biologia Estrutural e Bioimagem. Rio de Janeiro, RJ, Brasil / Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Biomagens - INBEB. Rio de Janeiro, RJ, Brasil.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Genômica Funcional e Bioinformática. Rio de Janeiro, RJ, Brasil.
National Institute of Mental Health. Bethesda, MD, USA / University of Pittsburgh. School of Medicine. Departmento of Neurobiology. Pittsburg, PA, USA.
Abstract: Background: Trypanosoma cruzi, the etiological agent of Chagas disease, is auxotrophic for arginine. It obtains this amino acid from the host through transporters expressed on the plasma membrane and on the membranes of intracellular compartments. A few cationic amino acid transporters have been characterized at the molecular level, such as the novel intracellular arginine/ornithine transporter, TcCAT1.1, a member of the TcCAT subfamily that is composed of four almost identical open reading frames in the T. cruzi genome. Methods: The functional characterization of the TcCAT1.1 isoform was performed in two heterologous expression systems. TcCAT subfamily expression was evaluated by real-time PCR in polysomal RNA fractions, and the cellular localization of TcCAT1.1 fused to EGFP was performed by confocal and immunoelectron microscopy. Results: In the S. cerevisiae expression system, TcCAT1.1 showed high affinity for arginine (Km = 0.085 ± 0.04 mM) and low affinity for ornithine (Km = 1.7 ± 0.2 mM). Xenopus laevis oocytes expressing TcCAT1.1 showed a 7-fold increase in arginine uptake when they were pre-loaded with arginine, indicating that transport is enhanced by substrates on the trans side of the membrane (trans-stimulation). Oocytes that were pre-loaded with [3 H]-arginine displayed a 16-fold higher efflux of [3 H]-arginine compared with that of the control. Analysis of polysomal RNA fractions demonstrated that the expression of members of the arginine transporter TcCAT subfamily is upregulated under nutritional stress and that this upregulation precedes metacyclogenesis. To investigate the cellular localization of the transporter, EGFP was fused to TcCAT1.1, and fluorescence microscopy and immunocytochemistry revealed the intracellular labeling of vesicles in the anterior region, in a network of tubules and vesicles. Conclusions: TcCAT1.1 is a novel arginine/ornithine transporter, an exchanger expressed in intracellular compartments that is physiologically involved in arginine homeostasis throughout the T. cruzi life cycle. The properties and estimated kinetic parameters of TcCAT1.1 can be extended to other members of the TcCAT subfamily.
Keywords: Arginine
Ornithine
Transporter
Protozoan
Trypanosomatids
T. cruzi
Parasite
Keywords in spanish: Transportador
DeCS: Arginina
Ornitina
Protozoários
Trypanosoma cruzi
Parasitos
Issue Date: 2015
Publisher: BioMed Central
Citation: HENRIQUES, Cristina et al. Identification and functional characterization of a novel arginine/ornithine transporter, a member of a cationic amino acid transporter subfamily in the Trypanosoma cruzi genome. Parasites & Vectors, v. 8, n. 346, p. 1-18, 2015.
DOI: 10.1186/s13071-015-0950-y
ISSN: 1756-3305
Copyright: open access
Appears in Collections:PR - ICC - Artigos de Periódicos
MS - Artigos de Periódicos
IOC - Artigos de Periódicos

Files in This Item:
File Description SizeFormat 
marcos_catanho_etal_IOC_2015.pdf2.86 MBAdobe PDFView/Open


FacebookTwitterDeliciousLinkedInGoogle BookmarksBibTex Format mendeley Endnote DiggMySpace

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.