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

---

Query: EC:1.9.3.1 (cytochrome oxidase)
8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The yeast PET1402/OXA1 gene encoding a 44.8-kDa protein is required for mitochondrial biogenesis. Substitution of Leu240 to serine in the protein results in an accumulation of the precursor form of the mitochondrially encoded subunit 2 of cytochrome oxidase (Cox2) and temperature-sensitive respiration. This temperature sensitivity can be suppressed by a mutation in the cox2 gene changing Ala189 of the Cox2 protein to proline. In the cox2-ts1402 double mutant respiration is restored without removal of the Cox2 pre-sequence. The suppression suggests an interaction of the Pet1402 protein with the cytochrome oxidase complex. Antibodies raised against the predicted C-terminus and the tagged N-terminus of the Pet1402 protein reacted with a 37-kDa polypeptide. This protein, present in the mitochondrial fraction, is localized within the inner membrane. The difference in size can be explained by the removal of the predicted mitochondrial-targeting sequence from the Pet1402 protein. The mitochondrial localization of the protein points to a direct interaction with the cytochrome oxidase complex.
...
PMID:A mutation in cytochrome oxidase subunit 2 restores respiration of the mutant pet ts1402. 916 11

In contrast to homologous genes in other fungal mitochondrial genomes, the gene encoding subunit 2 of cytochrome oxidase (cox2) in several Schizosaccharomyces pombe strains contains a large group II intron. Its 2436 nucleotides can be folded into a typical group II intron secondary structure, possessing all the expected sequence motifs for subgroup IIA1 (Michel et al., 1989). This intron is remarkable for the following reasons: (i) Five nucleotide changes were observed compared with the continuous form of the cox2 gene in the reference strain 50 at the 3'-exon sequence, but not in the 5'-exon. (ii) One of these changes occurred at the splice point leading to a serine instead of a threonine residue in the deduced cox2 polypeptide. In all cases, the alterations resulted in the replacement of more frequently used codons by rare ones. (iii) Although the intron is able to undergo splicing, the sequence motifs thought to be necessary for interaction between the 5'-exon and the intron during the splicing process (the EBS1/IBS1 as well as the EBS2/IBS2 pairings) are unusual. (iv) The intron is inserted at the same location in the cox2 gene as the otherwise unrelated intron from higher plants.
...
PMID:Mosaic structure of the cox2 gene in the petite negative yeast Schizosaccharomyces pombe: a group II intron is inserted at the same location as the otherwise unrelated group II introns in the mitochondria of higher plants. 965 94

We report the unique case of a 28-year-old man who, in spite of having a varicocele and a sperm concentration of 5 million/mL, of which 10% were motile and 20% had normal forms (oligoasthenoteratozoospermia [OAT]), was fertile. This was confirmed by paternity testing using 16 autosomal and 6 Y-chromosomal short tandem repeat (STR) loci. An analysis of mitochondrial genes that included cytochrome oxidase I (COI), cytochrome oxidase II (COII), adenosine triphosphate synthase6 (ATPase6), ATPase8, transfer ribonucleic acid (tRNA) serine I, tRNA lysine, and NADH dehydrogenase3 (ND3) revealed, for the first time, 9 missense and 27 silent mutations in the sperm's mitochondrial DNA (mtDNA) but not in the DNA from the blood cells. There was a 2-nucleotide deletion in the mitochondrial COII genes, introducing a stop codon, which might be responsible for low sperm motility.
...
PMID:Sperm mitochondrial mutations as a cause of low sperm motility. 1272 Dec 15

Fourteen-day-old Phaseolus vulgaris L. cv. Top Crop (bush bean) plants were sprayed with the plant growth stimulant, potassium naphthenate (20 mm). Seven days after treatment the contents of glutamic acid dehydrogenase, glutamic-oxaloacetic transaminase, nitrate reductase, glutamine synthetase, and cytochrome oxidase in the trifoliate leaf blades of treated plants were significantly larger, and the specific activity of the last four was significantly greater. Potassium nephthenate (1 mum) in the assay solutions did not significantly alter the activity of these enzymes in the cell-free extracts of untreated plants. Leaf discs from treated plants did not incorporate (14)C-leucine into protein more actively. The protein content of leaves of treated plants was 15.3% greater, and the percentages of 16 individual amino acids in the hydrolysates of the proteins of control and treated plants showed numerous differences. The major changes were greater percentages of glutamic acid, glycine, and proline, and smaller values of arginine, lysine, tyrosine, and leucine in protein of treated plants. The content of ethanol-soluble (free) amino acids was greater by 7.5%. The principal changes in content of these acids were larger percentages of arginine and lysine, and smaller values for glutamic acid, serine, and proline in the leaves of potassium naphthenate-treated plants. The content of DNA, measured 1, 2, and 3 weeks after a foliar application of potassium naphthenate, was not significantly different from that of untreated plants, but the amount of RNA was significantly greater at all three times of measurement. The number and weight of green pods per plant 30 days after potassium naphthenate application were significantly larger, suggesting that the stimulative action of potassium naphthenate was in progress at the times of the assays. A mechanism, involving a genetic and a metabolic phase, is suggested for the stimulation of plant growth by naphthenate.
...
PMID:Mechanism of plant growth stimulation by naphthenic Acid: effects on nitrogen metabolism of phaseolus vulgaris L. 1665 19

We have utilized an in situ rat coronary ligation model to establish a PKC-epsilon cytochrome oxidase subunit IV (COIV) coimmunoprecipitation in myocardium exposed to ischemic preconditioning (PC). Ischemia-reperfusion (I/R) damage and PC protection were confirmed using tetrazolium-based staining methods and serum levels of cardiac troponin I. Homogenates prepared from the regions at risk (RAR) and not at risk (RNAR) for I/R injury were fractionated into cell-soluble (S), 600 g low-speed centrifugation (L), Percoll/Optiprep density gradient-purified mitochondrial (M), and 100,000 g particulate (P) fractions. COIV immunoreactivity and cytochrome-c oxidase activity measurements estimated the percentages of cellular mitochondria in S, L, M, and P fractions to be 0, 55, 29, and 16%, respectively. We observed 18, 3, and 3% of PKC-delta, -epsilon, and -zeta isozymes in the M fraction under basal conditions. Following PC, we observed a 61% increase in PKC-epsilon levels in the RAR M fraction compared with the RNAR M fraction. In RAR mitochondria, we also observed a 2.8-fold increase in PKC-epsilon serine 729 phosphoimmunoreactivity (autophosphorylation), indicating the presence of activated PKC-epsilon in mitochondria following PC. PC administered before prolonged I/R induced a 1.9-fold increase in the coimmunoprecipitation of COIV, with anti-PKC-epsilon antisera and a twofold enhancement of cytochrome-c oxidase activity. Our results suggest that PKC-epsilon may interact with COIV as a component of the cardioprotection in PC. Induction of this interaction may provide a novel therapeutic target for protecting the heart from I/R damage.
...
PMID:Protein kinase C-epsilon coimmunoprecipitates with cytochrome oxidase subunit IV and is associated with improved cytochrome-c oxidase activity and cardioprotection. 1766 Mar 87

In the brain, ischemic preconditioning (IPC) diminishes mitochondrial dysfunction after ischemia and confers neuroprotection. Activation of epsilon protein kinase C (epsilonPKC) has been proposed to be a key neuroprotective pathway during IPC. We tested the hypothesis that IPC increases the levels of epsilonPKC in synaptosomes from rat hippocampus, resulting in improved synaptic mitochondrial respiration. Preconditioning significantly increased the level of hippocampal synaptosomal epsilonPKC to 152% of sham-operated animals at 2 d of reperfusion, the time of peak neuroprotection. We tested the effect of epsilonPKC activation on hippocampal synaptic mitochondrial respiration 2 d after preconditioning. Treatment with the specific epsilonPKC activating peptide, tat-psiepsilonRACK (tat-psiepsilon-receptor for activated C kinase), increased the rate of oxygen consumption in the presence of substrates for complexes I, II, and IV to 157, 153, and 131% of control (tat peptide alone). In parallel, we found that epsilonPKC activation in synaptosomes from preconditioned animals resulted in altered levels of phosphorylated mitochondrial respiratory chain proteins: increased serine and tyrosine phosphorylation of 18 kDa subunit of complex I, decreased serine phosphorylation of FeS protein in complex III, increased threonine phosphorylation of COX IV (cytochrome oxidase IV), increased mitochondrial membrane potential, and decreased H2O2 production. In brief, ischemic preconditioning promoted significant increases in the level of synaptosomal epsilonPKC. Activation of epsilonPKC increased synaptosomal mitochondrial respiration and phosphorylation of mitochondrial respiratory chain proteins. We propose that, at 48 h of reperfusion after ischemic preconditioning, epsilonPKC is poised at synaptic mitochondria to respond to ischemia either by direct phosphorylation or activation of the epsilonPKC signaling pathway.
...
PMID:Ischemic preconditioning targets the respiration of synaptic mitochondria via protein kinase C epsilon. 1841 96

Increased nuclear protein O-linked beta-N-acetylglucosamine glycosylation (O-GlcNAcylation) mediated by high glucose treatment or the hyperglycemia of diabetes mellitus contributes to cardiac myocyte dysfunction. However, whether mitochondrial proteins in cardiac myocytes are also submitted to O-GlcNAcylation or excessive O-GlcNAcylation alters mitochondrial function is unknown. In this study, we determined if mitochondrial proteins are O-GlcNAcylated and explored if increased O-GlcNAcylation is linked to high glucose-induced mitochondrial dysfunction in neonatal rat cardiomyocytes. By immunoprecipitation, we found that several mitochondrial proteins, which are members of complexes of the respiratory chain, like subunit NDUFA9 of complex I, subunits core 1 and core 2 of complex III, and the mitochondrial DNA-encoded subunit I of complex IV (COX I) are O-GlcNAcylated. By mass spectrometry, we identified that serine 156 on NDUFA9 is O-GlcNAcylated. High glucose treatment (30 mm glucose) increases mitochondrial protein O-GlcNAcylation, including those of COX I and NDUFA9 which are reduced by expression of O-GlcNAcase (GCA). Increased mitochondrial O-GlcNAcylation is associated with impaired activity of complex I, III, and IV in addition to lower mitochondrial calcium and cellular ATP content. When the excessive O-GlcNAc modification is reduced by GCA expression, mitochondrial function improves; the activity of complex I, III, and IV increases to normal and mitochondrial calcium and cellular ATP content are returned to control levels. From these results we conclude that specific mitochondrial proteins of cardiac myocytes are O-GlcNAcylated and that exposure to high glucose increases mitochondrial protein O-GlcNAcylation, which in turn contributes to impaired mitochondrial function.
...
PMID:Increased enzymatic O-GlcNAcylation of mitochondrial proteins impairs mitochondrial function in cardiac myocytes exposed to high glucose. 1900 14

Expression of the gdh2 gene encoding the alpha-subunit of mitochondrial glutamate dehydrogenase depends on redox state of the mitochondrial electron transport chain. Treatment of Arabidopsis thaliana cell suspension with antimycin A, a respiratory chain complex III inhibitor, resulted in an increase in gdh2 transcripts within 2 h. Inhibition of complex I by rotenone did not influence the transcript level, but treatment with potassium cyanide, a complex IV inhibitor, also increased the transcript content. Thus, gdh2 gene expression obviously responds to changes in the respiratory chain segment localized between complexes I and III. Lack of activation of gene expression after treatment of a cell suspension with hydrogen peroxide and the prooxidant paraquat and results of experiments with antioxidants suggest that gdh2 gene expression is not associated with increased content of reactive oxygen species generated during inhibition of the electron transport chain. Protein phosphorylation by serine/threonine protein kinases is the essential step required for signal transduction into nucleus resulting in the induction of gdh2 expression.
...
PMID:Induction of Arabidopsis gdh2 gene expression during changes in redox state of the mitochondrial respiratory chain. 1923 48

Mitochondrial dysfunction is increasingly recognized as a key component in compromised neuroendocrine stress response and, among other etiological causes, it may also involve action of glucocorticoid hormones. In the current study we followed glucocorticoid receptor and identified its mitochondrial phosphoisophorms in hippocampus and prefrontal brain cortex of Wistar male rats subjected to acute, chronic and combined neuroendocrine stresses. In both brain structures chronic social isolation caused marked increase in mitochondrial glucocorticoid receptor that was preferentially phosphorylated at serine 232 compared to serine 246 or serine 171. This increase corresponded with the decreased expression of mitochondrially encoded cytochrome oxidase subunits 1 and 3 in hippocampus, and with their increased expression in prefrontal brain cortex. Prefrontal brain cortex appeared to be more sensitive to chronic stress, since it exibited higher levels of mitochondrial Bax and cytoplasmic Bcl2 compared to hippocampus. Chronic stress also altered the response of both brain structures to subsequent acute stress according to the studied parameters. Therefore, prolonged social isolation may cause susceptibility to mitochondria triggered proapototic signalling, which at least in part may be mediated by the glucocorticoid receptor dependent mechanism.
...
PMID:The role of phosphorylated glucocorticoid receptor in mitochondrial functions and apoptotic signalling in brain tissue of stressed Wistar rats. 1978 50

Some cases of maternally inherited isolated deafness are caused by mtDNA mutations, frequently following an exposure to aminoglycosides. Two mitochondrial genes have been clearly described as being affected by mutations responsible for this pathology: the ribosomal RNA 12S gene and the transfer RNA serine (UCN) gene. A previous study identified several candidate novel mtDNA mutations, localized in a variety of mitochondrial genes, found in patients with no previous treatment with aminoglycosides. Five of these candidate mutations are characterized in the present study. These mutations are localized in subunit ND1 of complex I of the respiratory chain (m.3388C>A [p.MT-ND1:Leu28Met]), the tRNA for Isoleucine (m.4295A>G), subunit COII of complex IV (m.8078G>A [p.MT-CO2:Val165Ile]), the tRNA of Serine 2 (AGU/C) (m.12236G>A), and Cytochrome B, subunit of complex III (m.15077G>A [p.MT-CYB:Glu111Lys]). Cybrid cell lines have been constructed for each of the studied mtDNA mutations and functional studies have been performed to assess the possible consequences of these mutations on mitochondrial bioenergetics. This study shows that a variety of mitochondrial genes, including protein-coding genes, can be responsible for nonsyndromic deafness, and that exposure to aminoglycosides is not required to develop the disease, giving new insights on the molecular bases of this pathology.
...
PMID:Novel mitochondrial DNA mutations responsible for maternally inherited nonsyndromic hearing loss. 2224 83


<< Previous 1 2 3 Next >>

---