A putative pyruvate dehydrogenase α subunit gene fromTrypanosoma cruzi

Buscaglia, Carlos A.; Pollevick, Guido D.; Veloso, Cecilia; Lorca, Myriam; Frasch, Alberto C.C.; Sánchez, Daniel O.

doi:10.1016/s0167-4781(96)00140-6

Cited by 12 publications

(14 citation statements)

References 22 publications

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“…Although none of the dehydrogenases (PDHs) stimulated by Ca 2+ in vertebrates have been studied in detail in trypanosomatids 17 , the PDH E1α subunit seems to possess phosphorylation sites with similarity to those of the mammalian enzyme 33 , suggesting that, as the mammalian enzyme, it could be activated by Ca 2+ -stimulated dephosphorylation. Generation of acetyl-CoA by the pyruvate dehydrogenase is required for the formation of mitochondrial acetate, which translocates to the cytosol and is used for fatty acid synthesis 34 , a process that is required for efficient mouse infections by BSF trypanosomes 35 .…”

Section: Resultsmentioning

confidence: 99%

Essential regulation of cell bioenergetics in Trypanosoma brucei by the mitochondrial calcium uniporter

2013

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Mechanisms of regulation of mitochondrial metabolism in trypanosomes are not completely understood. Here we present evidence that the Trypanosoma brucei mitochondrial calcium uniporter (TbMCU) is essential for regulation of mitochondrial bioenergetics, autophagy, and cell death, even in the bloodstream forms that are devoid of a functional respiratory chain and oxidative phosphorylation. Localization studies reveal its co-localization with MitoTracker staining. TbMCU overexpression increases mitochondrial Ca2+ accumulation in intact and permeabilized trypanosomes, generates excessive mitochondrial reactive oxygen species (ROS), and sensitizes them to apoptotic stimuli. Ablation of TbMCU in RNAi or conditional knockout trypanosomes reduces mitochondrial Ca2+ uptake without affecting their membrane potential, increases the AMP/ATP ratio, stimulates autophagosome formation, and produces marked defects in growth in vitro and infectivity in mice, revealing its essentiality in these parasites. The requirement of TbMCU for proline and pyruvate metabolism in procyclic and bloodstream forms, respectively, reveals its role in regulation of mitochondrial bioenergetics.

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Section: Resultsmentioning

confidence: 99%

Essential regulation of cell bioenergetics in Trypanosoma brucei by the mitochondrial calcium uniporter

2013

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“…The single copy Pvdh gene [41] was included as internal reference to standardize the number of haploid genome copies in the test. Primers that amplify the region containing the single nucleotide polymorphism (SNP) that determines the loss of enzymatic activity were used together with two probes that differ in only one base (T/C transition) and comprise the Tyr codon (to hybridize aTS genes) or His codon (complementary to the sequence of iTS genes), respectively.…”

Section: Resultsmentioning

confidence: 99%

“…In the same reaction, a pair of fluorescent-labeled probes specific for the two possible sequences at the mutation position (5′-AATTCCGCC T ACAGCT-3′ coupled to FAM to detect aTS and 5′-AAAATTCCGCC C ACAGCT-3′ coupled to VIC which binds to iTS ) allowed the quantification of both genes. The analysis was normalized by quantification of the T. cruzi pyruvate dehydrogenase (PVDH)-encoding gene present as a single copy per haploid genome [41]. This reaction included a set of primers (5'-CGGCGTACCAGCCTGAGAT-3' and 5'-ACCTGAAGGCCCGGAATG-3') and a labeled probe (5'-TACCGTCGTGGCGACT-3') that hybridizes the pvdh gene.…”

Section: Methodsmentioning

confidence: 99%

Differential Distribution of Genes Encoding the Virulence Factor Trans-Sialidase along Trypanosoma cruzi Discrete Typing Units

et al. 2013

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Trypanosoma cruzi the agent of Chagas disease is a monophyletic but heterogeneous group conformed by several Discrete Typing Units (DTUs) named TcI to TcVI characterized by genetic markers. The trans-sialidase (TS) is a virulence factor involved in cell invasion and pathogenesis that is differentially expressed in aggressive and less virulent parasite stocks. Genes encoding TS-related proteins are included in a large family divided in several groups but only one of them contains TS genes. Two closely related genes differing in a T/C transition encode the enzymatically active TS (aTS) and a lectin-like TS (iTS). We quantified the aTS/iTS genes from TcII and TcVI aggressive and TcI low virulent strains and found variable aTS number (1–32) per haploid genome. In spite of being low TS enzyme-expressers, TcI strains carry 28–32 aTS gene copies. The intriguing absence of iTS genes in TcI strains together with the presence of aTS/iTS in TcII and TcVI strains (virulent) were observed. Moreover, after sequencing aTS/iTS from 38 isolates collected along the Americas encompassing all DTUs, the persistent absence of the iTS gene in TcI, TcIII and TcIV was found. In addition, the sequence clustering together with T/C transition analysis correlated to DTUs of T. cruzi. The consistence of TS results with both evolutionary genome models proposed for T. cruzi, namely the “Two Hybridization” and the “Three Ancestor” was discussed and reviewed to fit present findings. Parasite stocks to attempt genetic KO or to assay the involvement of iTS in parasite biology and virulence are finally available.

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“…In contrast, under glucose-rich conditions usually present in regular culture medium mitochondrial Ca 2+ could be stimulating the PDH phosphatase thereby activating pyruvate oxidation. In this regard, the PDH E1α subunit of trypanosomes seems to possess phosphorylation sites with similarity to those of the mammalian enzyme [99], suggesting that, as the mammalian enzyme, trypanosome PDH could be activated by Ca 2+ -stimulated dephosphorylation. The mitochondrial PDH is important for the generation of acetyl-coenzyme A (acetyl-CoA) that is required for the formation of acetate, which translocates to the cytosol and is used for fatty-acid synthesis [100].…”

Section: Role Of Mitochondrial Ca2+ Uptake In Trypanosomesmentioning

confidence: 99%

Mitochondrial calcium transport in trypanosomes

Docampo

Vercesi

Huang

2014

Molecular and Biochemical Parasitology

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The biochemical peculiarities of trypanosomes were fundamental for the recent molecular identification of the long-sought channel involved in mitochondrial Ca2+ uptake, the mitochondrial Ca2+ uniporter or MCU. This discovery led to the finding of numerous regulators of the channel, which form a high molecular weight complex with MCU. Some of these regulators have been bioinformatically identified in trypanosomes, which are the first eukaryotic organisms described for which MCU is essential. In trypanosomes MCU is important for buffering cytosolic Ca2+ changes and for activation of the bioenergetics of the cells. Future work on this pathway in trypanosomes promises further insight into the biology of these fascinating eukaryotes, as well as the potential for novel target discovery.

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A putative pyruvate dehydrogenase α subunit gene fromTrypanosoma cruzi

Cited by 12 publications

References 22 publications

Essential regulation of cell bioenergetics in Trypanosoma brucei by the mitochondrial calcium uniporter

Essential regulation of cell bioenergetics in Trypanosoma brucei by the mitochondrial calcium uniporter

Differential Distribution of Genes Encoding the Virulence Factor Trans-Sialidase along Trypanosoma cruzi Discrete Typing Units

Mitochondrial calcium transport in trypanosomes

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