Mitochondrial carrier family inventory of Trypanosoma brucei brucei: Identification, expression and subcellular localisation

Colasante, Claudia; Peña-Diaz, Priscila; Clayton, Christine; Voncken, Frank

doi:10.1016/j.molbiopara.2009.05.004

Cited by 54 publications

(85 citation statements)

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“…An obvious candidate for such an activity would be a homolog of the ATP-Mg/P i transporter, a protein that is responsible for the electroneutral exchange between ATP-Mg 2Ϫ and HPO 4 2Ϫ , which can supplement the mt ATP pool in cells using the hydrolytic activity of F o F 1 -ATPase to maintain the ⌬m (68). However, a putative T. brucei homolog of the ATP-Mg/P i transporter (Tb927.4.1660, MCP6) was shown to be inactive for ATP and ADP transport (25,69). Thus, besides TbAAC, any additional carrier(s) responsible for ATP influx into the mitochondria of this excavate protist remains to be elucidated.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, specific antibodies raised against T. brucei antigens were utilized: anti-enolase PAb (1:1,000) (36), anti-mt Hsp70 MAb (1:2,000) (37), anti-apocytochrome c PAb (1:1,000) (38), anti-COVI PAb (1:1,000) (33), anti-ATPaseTb2 PAb (1:1,000) (39), anti-␤ PAb (1:2,000), and p18 PAb (1:1,000). Additional T. brucei antibodies against TbVDAC (1:1000), putative TbP i C (Tb927.9.10310; 1:1,000) (25), TbAAC (1:1,000), and complex III subunit Rieske (1:1,000) were prepared commercially (Davids Biotechnology) by administering antigen-specific oligopeptides (TbVDAC, VDK SLK PGV LIT HS; TbP i C, SHP ADM LVS ARG KAS NVG KS; TbAAC, VDA LKP IYV EWR RSN; and complex III subunit Rieske, LSA LKH PET DEA RFP DHR E) to rabbits following a standard immunization protocol.…”

Section: Methodsmentioning

confidence: 99%

“…8.1310 and TbAAC, with the latter being represented by three identical and consecutively arranged genes (Tb927.10.14820, -30, and -40) and showing significant amino acid sequence similarity to functionally characterized AACs from other eukaryotes (25). Importantly, TbAAC exhibits biochemical properties and ADP/ATP exchange kinetics similar to the main yeast carrier, AAC2, while Tb927.8.1310 lacks the canonical sequence features required for ADP/ATP exchange activity (26).…”

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The ADP/ATP Carrier and Its Relationship to Oxidative Phosphorylation in Ancestral Protist Trypanosoma brucei

et al. 2015

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The highly conserved ADP/ATP carrier (AAC) is a key energetic link between the mitochondrial (mt) and cytosolic compartments of all aerobic eukaryotic cells, as it exchanges the ATP generated inside the organelle for the cytosolic ADP. Trypanosoma brucei, a parasitic protist of medical and veterinary importance, possesses a single functional AAC protein (TbAAC) that is related to the human and yeast ADP/ATP carriers. However, unlike previous studies performed with these model organisms, this study showed that TbAAC is most likely not a stable component of either the respiratory supercomplex III؉IV or the ATP synthasome but rather functions as a physically separate entity in this highly diverged eukaryote. Therefore, TbAAC RNA interference (RNAi) ablation in the insect stage of T. brucei does not impair the activity or arrangement of the respiratory chain complexes. Nevertheless, RNAi silencing of TbAAC caused a severe growth defect that coincides with a significant reduction of mt ATP synthesis by both substrate and oxidative phosphorylation. Furthermore, TbAAC downregulation resulted in a decreased level of cytosolic ATP, a higher mt membrane potential, an elevated amount of reactive oxygen species, and a reduced consumption of oxygen in the mitochondria. Interestingly, while TbAAC has previously been demonstrated to serve as the sole ADP/ATP carrier for ADP influx into the mitochondria, our data suggest that a second carrier for ATP influx may be present and active in the T. brucei mitochondrion. Overall, this study provides more insight into the delicate balance of the functional relationship between TbAAC and the oxidative phosphorylation (OXPHOS) pathway in an early diverged eukaryote. The origination event of an ADP/ATP carrier (AAC) was crucial in the evolution of the present-day mitochondrion that enabled it to become the powerhouse of the eukaryotic cell. Due to the activity of AAC, the energy-producing mitochondria can supply the cytosol with ATP molecules, which fuel most cellular reactions. AAC belongs to the well-defined family of mitochondrial (mt) carrier proteins that are located in the inner mt membrane and are involved in the transport of a wide range of metabolites (1). Under physiological aerobic conditions, AAC is responsible for the 1:1 counterexchange of mt ATP for cytosolic ADP (2). mt ATP is produced mainly by the evolutionarily conserved biochemical pathway of oxidative phosphorylation (OXPHOS), which employs respiratory complexes I through IV to convert the redox energy of various mt substrates into an electrochemical proton gradient (⌬m) across the mt inner membrane. Respiratory complexes I (NADH-ubiquinone oxidoreductase) and II (succinate-ubiquinone oxidoreductase) are responsible for the oxidation of reduced NADH and FADH 2 , respectively. The electrons derived from these biochemical processes continue along the electron transport chain as they are sequentially passed to coenzyme Q, complex III (ubiquinol-cytochrome c oxidoreductase), cytochrome c, complex IV (cytochrome c-O 2 oxid...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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The ADP/ATP Carrier and Its Relationship to Oxidative Phosphorylation in Ancestral Protist Trypanosoma brucei

et al. 2015

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“…MCF proteins are also responsible for AdoMet transport in yeast (13) and human mitochondria (14). Interestingly, Leishmania also encodes MCF proteins, one of which appears to be an orthologue of the mitochondrial AdoMet transporter (55). Disruption of the Arabidopsis SAMT1 gene led to a severe growth defect, but because the plants remained viable, it was suggested that other proteins could be implicated in AdoMet transport (15).…”

Section: Discussionmentioning

confidence: 99%

High Affinity S-Adenosylmethionine Plasma Membrane Transporter of Leishmania Is a Member of the Folate Biopterin Transporter (FBT) Family

Dridi¹,

Ouameur²,

Ouellette

2010

Journal of Biological Chemistry

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S-Adenosylmethionine (AdoMet) is an important methyl group donor that plays a central role in many essential biochemical processes. The parasite Leishmania can both synthesize and transport AdoMet. Leishmania cells resistant to the antifolate methotrexate due to a rearrangement in folate biopterin transporter (FBT) genes were cross-resistant to sinefungin, an AdoMet analogue. FBT gene rearrangements were also observed in Leishmania major cells selected for sinefungin resistance. One of the rearranged FBT genes corresponded to the main AdoMet transporter (AdoMetT1) of Leishmania as determined by gene transfection and gene inactivation experiments. AdoMetT1 was determined to be a high affinity plasma membrane transporter expressed constitutively throughout the growth phases of the parasite. Leishmania cells selected for resistance or naturally insensitive to sinefungin had lower expression of AdoMetT1. A new function in one carbon metabolism, also a pathway of interest for chemotherapeutic interventions, is described for a novel class of membrane proteins found in diverse organisms.The parasite Leishmania is distributed globally and causes a variety of clinical symptoms ranging from self-healing cutaneous lesions to visceral infections that are usually fatal if left untreated (1, 2). Current first-line chemotherapy against leishmaniasis relies on a rather limited arsenal of drugs, including pentavalent antimonials, liposomal amphotericin B, or miltefosine (2). These drugs are associated with side effects, high costs, and drug resistance, and therefore, the search for new drugs and targets to control this parasite is warranted (3, 4).S-Adenosylmethionine (AdoMet or SAM) 5 is an important biological sulfonium compound recognized as the universal methyl donor for methylation of lipids, proteins, nucleic acids, and xenobiotics in living cells (5). AdoMet is also a donor of propylamine groups for the synthesis of polyamines and participates in the reverse trans-sulfuration pathway where AdoMet is converted into cysteine and glutathione and in Leishmania in the spermidine-glutathione conjugate trypanothione (6, 7). AdoMet is also used as a source of methylene groups, amino groups, and ribosyl groups in the synthesis of fatty acids, biotin, and the modified nucleoside epoxyqueusine of tRNAs (reviewed in Ref. 8).Most cells are capable of synthesizing AdoMet from L-methionine and ATP, in a process requiring the enzyme methionine adenosyltransferase (MAT). The gene coding for this enzyme is present in most sequenced organisms (reviewed in Ref. 9). However, in some Rickettsia strains, the MAT gene is inactivated by a mutation (10), and in the fungus Pneumocystis carinii, no MAT activity has been detected (11). These organisms have the rare distinction of meeting their AdoMet needs by importing it (12). The Rickettsia transporter is part of the drug/ metabolite transporter superfamily (10), and the identity of the Pneumocystis transporter is not known. Transport of AdoMet across the plasma membrane does not occur to a signifi...

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“…ADP/ATP carriers have been extensively and predominantly studied in a wide range of higher eukaryotes (14,16), whereas virtually nothing is known about their homologues from earlier branching eukaryotes, such as the Kinetoplastida. We previously reported that the genome of T. brucei codes for 24 different MCF proteins (17). Two of the identified MCF proteins, TbMCP5 and TbMCP15, showed significant sequence similarity to functionally characterized ADP/ATP carriers from other eukaryotes (17).…”

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confidence: 99%

Functional Characterization of TbMCP5, a Conserved and Essential ADP/ATP Carrier Present in the Mitochondrion of the Human Pathogen Trypanosoma brucei

Peña-Diaz

Pélosi

Ebikeme

et al. 2012

Journal of Biological Chemistry

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Background:TbMCP5 was predicted to function as a mitochondrial ADP/ATP carrier. Results: TbMCP5 functionally complemented ANC-deficient S. cerevisae, has biochemical properties comparable with those of ScAnc2p, and is essential for mitochondrial ADP/ATP exchange in T. brucei. Conclusion: TbMCP5 is a conserved and essential mitochondrial ADP/ATP carrier in T. brucei. Significance: TbMCP5 is the first functionally characterized mitochondrial ADP/ATP carrier from a kinetoplastid parasite.

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Mitochondrial carrier family inventory of Trypanosoma brucei brucei: Identification, expression and subcellular localisation

Cited by 54 publications

References 74 publications

The ADP/ATP Carrier and Its Relationship to Oxidative Phosphorylation in Ancestral Protist Trypanosoma brucei

The ADP/ATP Carrier and Its Relationship to Oxidative Phosphorylation in Ancestral Protist Trypanosoma brucei

High Affinity S-Adenosylmethionine Plasma Membrane Transporter of Leishmania Is a Member of the Folate Biopterin Transporter (FBT) Family

Functional Characterization of TbMCP5, a Conserved and Essential ADP/ATP Carrier Present in the Mitochondrion of the Human Pathogen Trypanosoma brucei

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