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)

Among several bioactive substances known as coupling factors, transforming growth factor-beta (TGF-beta), interleukin-1 (IL-1), and prostaglandin (PG) E1 and E2 increased not only the activity of alkaline phosphatase but also the rate of incorporation of 45Ca2+ into ROS 17/2.8 during a 3-day culture: the former two factors are known to be formed at the site where bone is resorbed, while PG's are known as one of the factors involved in bone resorption. Parathyroid hormone, another hormone that affects bone metabolism, elevated the incorporation of 45Ca2+ by and decreased the alkaline phosphatase activity of the cells. The facts indicate the possibility that the osteoblastic cells are involved in the transport of calcium ions when bones are being resorbed. On the other hand, when these osteosarcoma cells were cultured in DMEM containing ascorbate and beta-glycerophosphate, followed by staining with silver nitrate by the procedure of von Kossa, there appeared many groups of cells that were positively stained as dark brown spots. Cells were then cultured under the same conditions in the presence of radioactive calcium, and the radioactivity accumulated was measured. The result showed that the presence of both ascorbate and beta-glycerophosphate in the culture medium dramatically increased the accumulation of 45Ca2+. It appears from these facts that ROS 17/2.8 cells are capable of incorporating and/or accumulating calcium ion if they are cultured under appropriate conditions. These cells will probably be able to produce a calcified matrix in vitro.
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PMID:[Effects of L-ascorbic acid and bone metabolism factors on alkaline phosphatase activity of and 45Ca2+ incorporation by ROS 17/2.8 cells]. 213 81

The effects of interleukin 1, transforming growth factor-beta (coupling factors), prostaglandin E1, and prostaglandin E2 on incorporation of 45Ca2+ and on alkaline phosphatase activity were studied using cultured ROS 17/2.8 cells, one of cell lines derived from rat osteosarcoma. We found that all these factors stimulate both the incorporation of 45Ca2+ and alkaline phosphatase activity of these cells. On the other hand, one of the bone resorption hormones, parathyroid hormone (PTH), suppressed the proliferation of cells and decreased the alkaline phosphatase activity at considerably low concentrations (1 X 10(-12)-1 X 10(-11) M). However, the hormone stimulated the incorporation of 45Ca2+ by these cells in a dose-dependent manner; the maximum stimulation on day 3 was observed at 1 X 10(-7) M and it was approximately 3 times the control value. The data suggest therefore, that the osteoblasts incorporated calcium ions and transported them while bone resorption was occurring. Thus the ROS 17/2.8 cell line appears to be an advantageous experimental system for the study of calcium metabolism of osteoblasts in vitro.
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PMID:[Effects of various factors involved in bone metabolism on 45Ca2+ incorporation and alkaline phosphatase activity of ROS 17/2.8 cells]. 260 4

The energetic consequences of strict oxyconformity in the intertidal worm S. nudus were studied by characterizing the Po2 dependence of respiration in mitochondria isolated from the body wall tissue. Mitochondrial respiration rose in a Po2 range between 2.8 and 31.3 kPa from a mean of 56.5 to 223.9 nmol O mg protein(-1) h(-1). Respiration was sensitive to both salicylhydroxamic acid (SHAM) and KCN. Po2 dependence remained unchanged with saturating and non-saturating substrate levels (malate, glutamate and ADP). A concomitant decrease of the ATP/O ratio revealed a lower ATP yield of aerobic metabolism at elevated Po2. Obviously, oxyconforming respiration implies progressive uncoupling of mitochondria. The decrease in ATP/O ratios at higher Po2 was completely reversible. Addition of 90.9 micromol H2O2 l(-1) did not inhibit ATP synthesis. Both observations suggest that oxidative injury did not contribute to oxyconformity. The contribution of the rates of mitochondrial ROS production and proton leakiness to mitochondrial oxygen consumption and uncoupling was investigated by using oligomycin as a specific inhibitor of the ATP synthase. The maximum contribution of oligomycin independent respiration to state 3 respiration remained below 6% and showed a minor, insignificant increase at elevated Po2, at a slope significantly lower than the increment of state 3 respiration. Therefore, Po2 dependent mitochondrial proton leakage or ROS production cannot explain oxyconformity. In conclusion Po2 dependent state 3 respiration likely relates to the progressive contribution of an alternative oxidase (cytochrome o), which is characterized by a low affinity to oxygen and an ATP/O ratio similar to the branched respiratory system of bacteria. The molecular nature of the alternative oxidase in lower invertebrates is still obscure.
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PMID:Oxyconformity in the intertidal worm Sipunculus nudus: the mitochondrial background and energetic consequences. 1133 54

Thyroid hormone plays an important role in bone development and metabolism. We used a polymerase chain reaction (PCR)-based mRNA differential display (DD) analysis to obtain a profile of thyroid hormone-responsive genes in osteoblast-like cells (ROS 17/2.8). ROS 17/2.8 cells were treated with 10(-8) M triiodothyronine (T(3)) for 2 and 24 hours. Total RNA was isolated, reverse-transcribed, and amplified using a total of 72 combinations (2 hours) and 240 combinations (24 hours) of 5' and 3' primers. At the 2-hour time point, 1 true-positive novel clone was identified and shown to be the mitochondrial gene, subunit 6 of ATP synthase (ATPase-6). At the 24-hour time point, 3 differentially expressed (DE) mRNAs were confirmed as true-positives including; nonmuscle alkali myosin light chain (NM aMLC), ATPase-6, and one novel clone. T(3)-induction of ATPase-6 mRNA in ROS 17/2.8 cells was seen at 2 and 4 hours, but was maximal at 24 hours (2.1-fold). T(3) induction of ATPase-6 mRNA was increased to fourfold in ROS 17/2.8 cells cultured at a low density. NM aMLC mRNA was modestly upregulated by T(3) in ROS 17/2.8 cells by 1.4-fold, and induction was augmented at low cell density to 1.7-fold. T(3) action on NM aMLC and on the mitochondrial gene ATPase 6, represent novel targets and potential mediators of thyroid hormone action on bone. Cell type, and the extent of cell differentiation, influences T(3) regulation of genes in osteoblast-derived cells.
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PMID:Thyroid hormone gene targets in ROS 17/2.8 osteoblast-like cells identified by differential display analysis. 1222 34

Primary disorders of mitochondrial ATP synthase belong to the most severe mitochondrial diseases. They can be caused by heteroplasmic mtDNA mutations in ATP6 gene that affect ability of enzyme to synthesise ATP, or by mutations in nuclear genes encoding factors essential for biosynthesis and assembly of the catalytic F1-part of the enzyme. In the latter case the cellular content of the enzyme decreases to < or = 30%. In both types of defects low production of ATP appears to be associated with increased mitochondrial ROS production related to elevated levels of mitochondrial membrane potential.
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PMID:[Hereditary disorders of mitochondrial ATP synthase]. 1544 54

Isolated defects of mitochondrial ATPase due to diminished biosynthesis of the enzyme represent new class of severe mitochondrial diseases of nuclear origin. The primary cause of decreased cellular content of ATPase appears to be a problem in assembly of the F1 catalytic part of the enzyme. With the aim to elucidate how the low ATPase content affects mitochondrial energy provision and ROS production, we have investigated fibroblasts from patients with ATPase decrease to 10-30%. Measurements of cellular respiration showed pronounced decrease in ATPase capacity for basal respiration, mitochondrial ATP synthesis was decreased to 26-33%. Cytofluorometric analysis using TMRM revealed altered discharge of mitochondrial membrane potential (DeltaPsim) in patient cells, which was 20 mV increased at state 3-ADP. Analysis of ROS production by CM-H2DCFDA demonstrated 2-fold increase in ROS production in patient cells compared to controls. ROS production rate was sensitive to uncoupler (FCCP) and thus apparently related to increased DeltaPsim. Our studies clearly demonstrate that low ATPase content and decreased mitochondrial ATP production lead to high values of DeltaPsim and are associated with activation of ROS generation by the mitochondrial respiratory chain. In conclusion, both the energetic deprivation and increased oxidative stress are important components of the pathogenic mechanism of ATPase disorders.
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PMID:Two components in pathogenic mechanism of mitochondrial ATPase deficiency: energy deprivation and ROS production. 1658 Dec 17

ATP synthase is a key enzyme of mitochondrial energy conversion. In mammals, it produces most of cellular ATP. Alteration of ATP synthase biogenesis may cause two types of isolated defects: qualitative when the enzyme is structurally modified and does not function properly, and quantitative when it is present in insufficient amounts. In both cases the cellular energy provision is impaired, and diminished use of mitochondrial DeltamuH+ promotes ROS production by the mitochondrial respiratory chain. The primary genetic defects have so far been localized in mtDNA ATP6 gene and nuclear ATP12 gene, however, involvement of other nuclear genes is highly probable.
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PMID:Mitochondrial diseases and genetic defects of ATP synthase. 1673 Jun 39

Singlet oxygen is reported to have the most potent damaging effect upon the photosynthetic machinery. Usually this reactive oxygen molecule acts in concert with other ROS types under stressful conditions. To understand the specific role of singlet oxygen we took advantage of the conditional flu mutant of Arabidopsis thaliana. In flu, the negative feedback loop is abolished, which blocks chlorophyll biosynthesis in the dark. Therefore high amounts of free protochlorophyllide accumulate during darkness. If flu gets subsequently illuminated, free protochlorophyllide acts as a photosensitiser leading almost exclusively to high amounts of (1)O2. Analysing the thylakoid protein pattern by using 2D PAGE and subsequent MALDI-TOF analysis, we could show, in addition to previous described effects on photosystem II, that singlet oxygen has a massive impact on the thylakoid ATP synthase, especially on its gamma subunit. Additionally, it could be shown that the activity of the ATP synthase is reduced upon singlet oxygen exposure and that the rate of non-photochemical quenching is affected in flu mutants exposed to (1)O2.
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PMID:Singlet oxygen affects the activity of the thylakoid ATP synthase and has a strong impact on its gamma subunit. 1710 25

Analysis of the protein profile of mitochondria and its age-dependent variation is a promising approach to unravel mechanisms involved in aging and age-related diseases. Our studies focus on the mammalian mitochondrial membrane proteome, especially of the inner mitochondrial membrane with the respiratory chain complexes and other proteins possibly involved in life-span control and aging. Variations of the mitochondrial proteome during aging, with the emphasis on the abundance, composition, structure, and activity of membrane proteins, are examined in various rat tissues by native polyacrylamide gel electrophoresis techniques in combination with MALDI-TOF mass spectrometry. In rat brain, age-modulated differences in the abundance of various mitochondrial and nonmitochondrial proteins, such as Na,K-ATPase, HSP60, mitochondrial aconitase-2, V-type ATPase, MF(o)F(1) ATP synthase, and the OXPHOS complexes I-IV are detected. During aging, a decrease in the amount of intact MF(o)F(1) ATP synthase occurs in the cortex. As analytical technique, native PAGE separates not only individual proteins but also multi-subunit (membrane) proteins, (membrane) protein supercomplexes as well as interacting proteins in their native state. It reveals the occurrence and architecture of supramolecular assemblies of proteins. The age-related alterations in the oligomerization of the MF(o)F(1) ATP synthase observed by us in rat cortex might be one clue for understanding the link between respiration and longevity. Also, the abundance of OXPHOS supercomplexes, that is, the natural assemblies of the respiratory complexes I, III, and IV into supramolecular stoichiometric entities, such as I(1)III(2)IV(0-4), can differ between young and aged cortex tissue. Age-related changes in the supramolecular architecture of OXPHOS complexes might explain alterations in ROS production during aging.
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PMID:Proteome alterations in rat mitochondria caused by aging. 1746 Jan 90

Two point mutations (T>G and T>C) at the same 8993 nucleotide of mitochondrial DNA (at comparable mutant load), affecting the ATPase 6 subunit of the F1F0-ATPase, result in neurological phenotypes of variable severity in humans. We have investigated mitochondrial function in lymphocytes from individuals carrying the 8993T>C mutation: the results were compared with data from five 8993T>G NARP (Neuropathy, Ataxia and Retinitis Pigmentosa) patients. Both 8993T>G and 8993T>C mutations led to energy deprivation and ROS overproduction. However, the relative contribution of the two pathogenic components is different depending on the mutation considered. The 8993T>G change mainly induces an energy deficiency, whereas the 8993T>C favours an increased ROS production. These results possibly highlight the different pathogenic mechanism generated by the two mutations at position 8993 and provide useful information to better characterize the biochemical role of the highly conserved Leu-156 in ATPase 6 subunit of the mitochondrial ATP synthase complex.
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PMID:Biochemical phenotypes associated with the mitochondrial ATP6 gene mutations at nt8993. 1756 59


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