Modeling of ATP–ADP steady‐state exchange rate mediated by the adenine nucleotide translocase in isolated mitochondria

Metelkin, Eugeniy; Demin, Oleg; Kovács, Zsuzsanna; Chinopoulos, Christos

doi:10.1111/j.1742-4658.2009.07394.x

Cited by 51 publications

(69 citation statements)

References 65 publications

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“…Increasing the level of ATP beyond this point tended to suppress transcription at HSP1 while preserving HSP2 transcription. The levels at which a decline in HSP1 transcription is seen are within the range of expected matrix ATP concentration, suggesting the relevance of this process to physiological regulation (27). The loss of HSP1 expression at ATP concentrations greater than 1 mM has been previously observed in transcription driven by HeLa cell mitochondrial extract (12).…”

Section: Discussionmentioning

confidence: 74%

Transcriptional requirements of the distal heavy-strand promoter of mtDNA

Zollo

Tiranti

Sondheimer

2012

Proc. Natl. Acad. Sci. U.S.A.

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The heavy strand of mtDNA contains two promoters with nonoverlapping functions. The role of the minor heavy-strand promoter (HSP2) is controversial, because the promoter has been difficult to activate in an in vitro system. We have isolated HSP2 by excluding its interaction with the more powerful HSP1 promoter, and we find that it is transcribed efficiently by recombinant mtRNA polymerase and mitochondrial transcription factor B2. The mitochondrial transcription factor A is not required for initiation, but it has the ability to alternatively activate and repress the HSP2 transcriptional unit depending on the ratio between mitochondrial transcription factor A and other transcription factors. The positioning of transcriptional initiation agrees with our current understanding of HSP2 activity in vivo. Serial deletion of HSP2 shows that only proximal sequences are required. Several mutations, including the disruption of a polycytosine track upstream of the HSP2 initiation site, influence transcriptional activity. Transcription from HSP2 is also observed when HeLa cell mitochondrial extract is used as the source of mitochondrial polymerase, and this transcription is maintained when HSP2 is provided in proper spacing and context to the HSP1 promoter. Studies of the linked heavy-strand promoters show that they are differentially regulated by ATP dosage. We conclude that HSP2 is transcribed and has features that allow it to regulate mitochondrial mRNA synthesis.mitochondrial biology | organelle T he mitochondrial genome (mtDNA) encodes 13 proteins that are constituents of the electron transport chain and ATP synthase. Transcription of mtDNA proceeds bidirectionally, radiating out from the noncoding D-loop. The light-strand promoter (LSP) is required for the synthesis of ND6 mRNA and eight of the mitochondrial tRNAs (1). Transcription from LSP also primes the origin of heavy-strand replication, which is the first step in the synthesis of mtDNA (2).The heavy strand encodes 12 mRNAs, both mitochondrial rRNAs and the remaining tRNAs. Intracellular levels of mature rRNAs are in great excess to the mRNAs (3). Although it was initially proposed that this imbalance was caused by the existence of a single initiation site, with most primary transcripts terminating before reaching the protein coding region, later studies used a combination of ribonucleotide incorporation assays and capping of precursor transcripts to suggest the existence of two distinct heavy-strand initiation sites in close proximity (4-6). The first heavy-strand promoter (HSP1), which lies fully within the Dloop, is responsible for the synthesis of a transcript composed of the 12S and 16S rRNAs and intervening tRNAs (Fig. 1A). The minor or distal heavy-strand promoter (HSP2) initiates within the sequence of the mitochondrial tRNA for phenylalanine. HSP2-initiated transcription produces the remaining mitochondrial mRNAs by processing nearly the full length of the mtDNA.Studies of HSP2 promoter function are complicated by its unusual position, both within a tRNA-...

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Section: Discussionmentioning

confidence: 74%

Transcriptional requirements of the distal heavy-strand promoter of mtDNA

Zollo

Tiranti

Sondheimer

2012

Proc. Natl. Acad. Sci. U.S.A.

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“…The effectiveness of PS10 as a PDK inhibitor in vivo is established by higher PDC activity in most tissues from PS10-treated over vehicle-treated DIO mice. The stimulation of PDC activity in the liver and heart is compelling, given that PS10 is competitive with ATP, which is usually present at 1-10 mM in the mitochondrial matrix (44,45). The results may be explained by the accumulation of PS10 in the mitochondrial matrix.…”

Section: Discussionmentioning

confidence: 99%

Structure-guided Development of Specific Pyruvate Dehydrogenase Kinase Inhibitors Targeting the ATP-binding Pocket

Tso¹,

Gui

et al. 2014

Journal of Biological Chemistry

105

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Background: Up-regulated pyruvate dehydrogenase kinase isoforms (PDKs) are associated with impaired glucose homeostasis in diabetes. Results: Novel PDK inhibitors were developed using structure-based design, which improves glucose tolerance with reduced hepatic steatosis in diet-induced obese mice. Conclusion: Obesity phenotypes are effectively treated by chemical intervention with PDK inhibitors. Significance: PDKs are potential drug targets for obesity and type 2 diabetes.

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“…To determine the adenine nucleotide content of the extracts, a modified HPLC-based method was used (Metelkin et al 2009). The HPLC system (DIONEX, Sunnyvale, USA; P680 HPLC Pump, ASI-100 Automated Sample Injector, Thermostatted Column Compartment TCC-100, PDA-100 Photodiode Array) was used with a C18-reversedphase column (ACE 5 C18; 250 × 4.6 mm; particle size 5 µm, Advanced Chromatography Technologies, Aberdeen, Scotland) equilibrated with 215 mM KH 2 PO 4 , 0.4 % KOH, 2 % acetonitrile, 4.6 mM tetrabutylammoniumhydroxide at a flow rate of 1 ml/min.…”

Section: Analytical Proceduresmentioning

confidence: 99%

A low phosphorylation potential in the acetogen Acetobacterium woodii reflects its lifestyle at the thermodynamic edge of life

2015

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The anaerobic, acetogenic bacterium Acetobacterium woodii grows on hydrogen and carbon dioxide and uses the Wood-Ljungdahl pathway to fix carbon but also to synthesize ATP. The free energy change of acetogenesis from H2 + CO2 allows for synthesis of only a fraction of an ATP under environmental conditions, and A. woodii is clearly a paradigm for microbial life under extreme energy limitation. However, it was unknown how much energy is required to make ATP under these conditions. In the present study, we determined the phosphorylation potential in cells metabolizing three different acetogenic substrates. It accounts to 37.9 ± 1.3 kJ/mol ATP during acetogenesis from fructose, 32.1 ± 0.3 kJ/mol ATP during acetogenesis from H2 + CO2 and 30.2 ± 0.9 kJ/mol ATP during acetogenesis from CO, the lowest phosphorylation potential ever described. The physiological consequences in terms of energy conservation under extreme energy limitation are discussed.

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Modeling of ATP–ADP steady‐state exchange rate mediated by the adenine nucleotide translocase in isolated mitochondria

Cited by 51 publications

References 65 publications

Transcriptional requirements of the distal heavy-strand promoter of mtDNA

Transcriptional requirements of the distal heavy-strand promoter of mtDNA

Structure-guided Development of Specific Pyruvate Dehydrogenase Kinase Inhibitors Targeting the ATP-binding Pocket

A low phosphorylation potential in the acetogen Acetobacterium woodii reflects its lifestyle at the thermodynamic edge of life

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