Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.3.14 (ATP synthase)
7,042 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Different mitochondrial mutants have been isolated that affect mitochondrial ribosome function. These mutants were used to establish most of the known methods and principles of mitochondrial genetics in yeast. Another class of mitochondrial mutants have been shown to affect mitochondrial ATPase and, more specifically, the "membrane factor" of mitochondrial ATPase. These mutants might be very useful in studying the energy-conserving function, and the interaction between the hydrophobic and hydrophylic parts, of the ATPase complex. New types of mitochondrial point mutations, concerning cytochrome a-a3 or b, will soon open up new fields of investigation. The biochemical and genetic analysis of numerous mutants belonging to that category and recently obtained [31] is being currently pursued in Tzagoloff's and Slonimski's laboratories.
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PMID:Genetic analysis of mitochondrial biogenesis and function in Saccharomyces cerevisiae. 13 34

The mitochondrial phosphate carrier is inhibited by the SH reagents p-(hydroxymercuri)benzoate and N-ethylmaleimide. Based on an analysis utilizing dodecyl sulfate-polyacrylamide gels, an SH-containing 32 000-dalton protein has been identified as a component of the phosphate carrier system. Two other N-[3H]ethylmaleimide-labeled proteins of the inner mitochondrial membrane have been eliminated from this role [Wholrab, H., & Greaney, J., Jr. (1978) Biochim. Biophys. Acta 503, 425] on the basis that band IV (45,000 daltons) is absent from heart sonic submitochondrial particles and band VII (6 500 daltons) does not react with p-(hydroxymercuri)benzoate. The mobility of the 32 000-dalton protein (0.43) is lower than that of the gamma subunit of the mitochondrial ATPase (0.46) and the carboxyatractyloside binding protein (0.48) on 12.5% dodecyl sulfate-polyacrylamide gels. In these flight muscle mitochondria, 0.87 nmol of N-[3H]ethylmaleimide per nmol of cytochrome a is bound to the 32,000-dalton protein.
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PMID:Identification of the N-ethylmaleimide reactive protein of the mitochondrial phosphate transporter. 43 69

Preparations enriched in Chlamydomonas reinhardtii thylakoids have proven useful in the study of photosynthesis. Many of their polypeptides however remain unidentified. We report here on three of those, h1 (34 kDa), h2 (11 kDa), and P3 (63 kDa). h1, h2, and P3 are present in all tested mutants of C. reinhardtii lacking either one or several of the photosynthetic chain complexes or depleted in thylakoid membranes. h2 is an ascorbate-reducible, soluble c550-type cytochrome encoded in the nucleus. It cross-reacts immunologically with mitochondrial cytochromes c from various sources and contains a hexapeptide encoded in C. reinhardtii cytochrome c cDNA. P3, a nuclear-encoded peripheral protein, cross-reacts with various ATP synthase beta subunits. Its N-terminal sequence is encoded in C. reinhardtii mitochondrial beta subunit cDNA. h1 behaves as an integral hemoprotein; it is absent in a mitochondrial mutant that carries a deletion in apocytochrome b gene. We conclude that C. reinhardtii mitochondrial membranes copurify with thylakoid membranes. h1 is part of the cytochrome bc1 complex, h2 is cytochrome c, and P3 is the beta subunit of mitochondrial ATP synthase.
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PMID:Identification of mitochondrial proteins in membrane preparations from Chlamydomonas reinhardtii. 130 33

Thyroid hormone is one of the few known physiological regulators of mammalian mitochondrial biogenesis. Although it exerts a global effect on biogenesis, it does so by regulating the expression of a limited number of unidentified mitochondrial proteins. We have investigated these hormone-regulated proteins in rat liver. Hormone injection induced a 30-fold increase in the levels of cytochrome-c1 mRNA after 3 d. In addition, the mRNA for the growth-activated adenine-nucleotide translocator, ANT2, was increased 13-fold and that for the ATPase N,N'-dicyclohexylcarbodiimide-binding protein increased 4-5-fold. Mitochondrial transcripts of cytochrome-oxidase subunit I also increased. No changes were found in the mRNA levels for the F1-ATPase beta-subunit or cytochrome oxidase IV. A single low dose of triiodothyronine induces rapid increases in cytochrome-c1 and ANT2 mRNA species which parallel changes in the activity of the hormone-responsive malic enzyme, but are earlier than other mitochondrial biogenetic events. These data strengthen the view that thyroid hormone regulates synthesis of specific components within each respiratory-chain complex and that these products apparently play key roles in inner-membrane biogenesis and assembly. The significance of ANT2 induction is also discussed with respect to the rapid respiratory response induced by thyroid hormone.
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PMID:Transcript levels for nuclear-encoded mammalian mitochondrial respiratory-chain components are regulated by thyroid hormone in an uncoordinated fashion. 132 Oct 44

Mitochondrial protein, cytochrome-c-oxidase and mitochondrial ATPase activities, which can participate in brown adipose tissue thermogenesis, were measured in the present study in order to evaluate mitochondrial activity, oxidative capacity and ATP synthesis in dietary obese rats compared to control rats. Cafeteria-diet induced increase of cytochrome-c-oxidase and ATPase activities of 54% and 37% respectively, but mitochondrial protein content remained unchanged. Fasting induced active mitochondrial protein degradation (about 50%) only in control rats, but in both cafeteria fed and post-cafeteria obese rats fasting-induced loss of mitochondrial protein was impaired. It was concluded that cafeteria diet is able to induce specifically both the oxidative capacity and the ATP synthesis in adult rat brown adipose tissue without affecting the mitochondrial protein. Furthermore, during fasting the obese (or overweight) status 'per se' regulates the overall mitochondrial protein degradation which was impaired or inactivated in overweight dietary rats compared with controls.
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PMID:Dietary regulation of fasting-induced mitochondrial protein degradation in adult rat brown adipose tissue. 133 18

Biogenesis of mammalian mitochondria requires the participation of both nuclear and mitochondrial genes. In order to study the expression and coordination of these two sets of genes, serum-deprived, quiescent NIH 3T3 cells were activated by serum addition. The steady-state levels of the transcripts for two growth-response genes (the mitochondrial adenine-nucleotide translocator and non-mitochondrial beta-actin), one nuclear-encoded respiratory-chain component (F1-ATPase beta-subunit) and the mitochondrial-encoded subunit I of cytochrome oxidase decreased significantly in quiescent cells and were rapidly restored with similar kinetics after addition of serum. The transcripts for two additional nuclear-encoded mitochondrial genes (cytochrome c1 and cytochrome oxidase subunit IV) did not respond to serum deprivation or growth activation. These results imply that mitochondrial biogenesis is at least partially regulated through growth-dependent mechanisms. Furthermore, the expression of nuclear genes encoding mitochondrial respiratory-chain components does not appear to be tightly coordinated, suggesting the existence of multiple control circuits.
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PMID:Differential regulation of the transcript levels of some nuclear-encoded and mitochondrial-encoded respiratory-chain components in response to growth activation. 137 2

This paper reports studies of bioenergetic modifications in a TTR1 single-nuclear mutant, isolated as resistant to triethyltin, an inhibitor of mitochondrial ATPase, and effective in cAMP-dependent protein phosphorylation. This mutant appears to have lost the wild-type cell ability to respond to a decrease of oxygen concentration in the growth medium by a decrease of cytochrome concentration in the cell. ATP synthesis rate in mutant cells in both the prestationary and stationary phase of growth appeared increased in comparison to wild-type cells, as too was respiration rate. A comparative study of mitochondria extracted from wild-type and from TTR1 mutant cells showed an increase in respiration rate, an increase in ATP synthesis rate, and an increase in TPP+ uptake in mutant mitochondria. The specific ATPase activity, as well as its sensitivity to TET, appears to be similar for mitochondria extracted from both strains. It was proposed that the modification of mitochondrial biogenesis in the TTR1 mutant may be due to a response of the cell to an increase in ATP hydrolysis caused by the mutation. It is also possible that the modification in cAMP-dependent protein kinase regulation which appeared to occur in this mutant affects protein(s) involved in mitochondrial biogenesis.
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PMID:Mitochondrial modifications in a single nuclear mutant of Saccharomyces cerevisiae affected in cAMP-dependent protein phosphorylation. 216 72

The yeast mitochondrial outer membrane contains a major 70 kd protein with an amino-terminal hydrophobic membrane anchor and a hydrophilic 60 kd domain exposed to the cytosol. We now show that this protein (which we term MAS70) accelerates the mitochondrial import of many (but not all) precursor proteins. Anti-MAS70 IgGs or removal of MAS70 from the mitochondria by either mild trypsin treatment or by disrupting the nuclear MAS70 gene inhibits import of the F1-ATPase beta-subunit, the ADP/ATP translocator, and of several other precursors into isolated mitochondria by up to 75%, but has little effect on the import of porin. Intact cells of a mas70 null mutant import the F1-ATPase alpha-subunit and beta-subunits, cytochrome c1 and other precursors at least several fold more slowly than wild-type cells. Removal of MAS70 from wild-type mitochondria inhibits binding of the ADP/ATP translocator to the mitochondrial surface, indicating that MAS70 mediates one of the earliest import steps. Several precursors are thus imported by a pathway in which MAS70 functions as a receptor-like component. MAS70 is not essential for import of these precursors, but only accelerates this process.
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PMID:Protein import into yeast mitochondria is accelerated by the outer membrane protein MAS70. 217 Jan 6

The system coordinating expressions of nuclear coded mitochondrial proteins was investigated by examination of the 5'-flanking region of the human mitochondrial ATP synthase beta-subunit gene. The promoter activity was measured by a transient expression of a chloramphenicol acetyltransferase (CAT) gene connected with various 5'-deletion mutants of the 5'-flanking region. In this experiment, at least two regions enhanced this promoter activity and at least one region repressed it. In one of the enhancing regions, a consensus sequence was found for the genes of other mitochondrial proteins such as those for cytochrome c1 (Suzuki, H., Hosokawa, Y., Nishikimi, M., and Ozawa, T. (1989) J. Biol. Chem. 264, 1368-1374) and the pyruvate dehydrogenase alpha-subunit (Maragos, C., Hutchison, W. M., Hayasaka, K., Brown, G. K., and Dahl, H.-H. M. (1989) J. Biol. Chem. 264, 12294-12298; Ohta, S., Endo, H., Matsuda, K., and Kagawa, Y. (1989) Ann. N. Y. Acad. Sci. 573, 458-460). The characteristics of this enhancing element were examined by introducing a synthetic oligonucleotide element into the CAT plasmid with a deleted enhancing element. The resulting plasmid showed full recovery of promoter activity, and this activity was independent of the orientation or location of the insert. Therefore, this is an enhancer that may be common to the nuclear genes of some mitochondrial proteins involved in energy transduction.
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PMID:Novel regulatory enhancer in the nuclear gene of the human mitochondrial ATP synthase beta-subunit. 218 18

1. Mitochondrial ATP synthesis (oxidative phosphorylation) is mainly regulated by the membrane potential (respiratory control) and protein synthesis (transcriptional control). 2. According to the current view, genes for enzymes of oxidative phosphorylation are classified as housekeeping genes that are transcribed constitutively. These genes have been sequenced. 3. Four complexes of oxidative phosphorylation (complexes I, III and IV, and ATP synthase) are exceptional oligomers that contain subunits encoded by mitochondrial DNA. The remaining subunits of these complexes, as well as thousands of other mammalian enzymes are encoded by nuclear DNA. 4. It is proposed that ATP synthase (F0F1) and these oligomers supplying energy to F0F1, though they are housekeeping, are under some coordinated transcriptional control. Not transcription, but translation of mitochondrial DNA is mainly regulated. 5. Recently, studies on cloned human genes for the FoF1 beta subunit and 7 enzymes related to ATP synthesis revealed coordinated transcription. Moreover, a novel common cis-element (enhancer) was discovered in the 5'-upstream region of genes for the F1 beta subunit, cytochrome c1 and pyruvate dehydrogenase E1 alpha subunit. 6. In contrast to heme control and catabolite repression of yeast via trans-acting elements such as HAP and GP, signal transduction and coordinated transcription of human oxidative phosphorylation is not directed by CP1 (a HAP homolog), but may be closely related to cell differentiation.
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PMID:Regulation of mitochondrial ATP synthesis in mammalian cells by transcriptional control. 218 63


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