Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A protein phosphatase was purified from the stroma of Pea (Pisum sativum L.) chloroplasts that is capable of dephosphorylating synthetic phosphopeptides. Following chromatographic purification of greater than 400-fold, two-dimensional electrophoresis indicated that the stromal protein phosphatase is a 29-kD protein. A similar molecular size was determined for the protein-phosphatase activity using gel-permeation chromatography, indicating that the stromal protein phosphatase is probably a monomer. The purified enzyme was able to dephosphorylate synthetic phosphopeptides, which mimic the thylakoid light-harvesting complex II (LHC-II) N terminus, as well as LHC-II in thylakoid membranes, but did not dephosphorylate the major 64-kD phosphoprotein in the stroma. The stromal protein phosphatase did not discriminate between dephosphorylation of phosphothreonine and phosphoserine residues in synthetic peptide substrates, providing further evidence that this enzyme is distinct from the protein phosphatase localized in thylakoid membranes. The exact physiological role of the stromal protein phosphatase has yet to be determined, but it may function in the dephosphorylation of LHC-II.
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PMID:Purification of a protein phosphatase from chloroplast stroma capable of dephosphorylating the light-harvesting complex-II. 906 87

Huntington's disease (HD) is a genetic neurodegenerative disorder characterized by motor abnormalities and cognitive impairment. The irreversible succinate dehydrogenase (SD) inhibitor 3-nitropropionic acid (3NP) causes neurodegeration in the striatum resembling HD when administered to rodents or primates. Using corticostriatal brain slice preparations, we analyzed the pattern of gene expression following 3NP application utilizing cDNA microarrays. Acute 3NP treatment modulates the expression of several genes involved in dopaminergic and glutamatergic signaling in corticostriatal brain slices, and unbalances the downstream serine/threonine protein kinase and phosphatase network affecting the dopamine- and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32). Our data provide new information about the molecular events possibly underlying neurodegeneration induced by this mitochondrial toxin.
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PMID:Inhibition of mitochondrial complex II alters striatal expression of genes involved in glutamatergic and dopaminergic signaling: possible implications for Huntington's disease. 1500 11

We have raised monoclonal antibodies capable of immunocapturing all five complexes involved in oxidative phosphorylation for evaluating their post-translational modifications. Complex I (NADH dehydrogenase), complex II (succinate dehydrogenase), complex III (cytochrome c reductase), complex IV (cytochrome c oxidase), and complex V (F1F0 ATP synthase) from bovine heart mitochondria were obtained in good yield from small amounts of tissue in more than 90% purity in one step. The composition and purity of the complexes was evaluated by Western blotting using monoclonal antibodies against individual subunits of the five complexes. In this first study, the phosphorylation state of the proteins without inducing phosphorylation or dephosphorylation was identified by using the novel Pro-Q Diamond phosphoprotein gel stain. The major phosphorylated components were the same as described before in sucrose gradient enriched complexes. In addition a few additional potential phosphoproteins were observed. Since the described monoclonal antibodies show cross reactivity to human proteins, this procedure will be a fast and efficient way of studying post-translational modifications in control and patient samples using only small amounts of tissue.
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PMID:Focused proteomics: monoclonal antibody-based isolation of the oxidative phosphorylation machinery and detection of phosphoproteins using a fluorescent phosphoprotein gel stain. 1530 Jul 71

Phosphorylated thylakoid proteins of spinach (Spinacia oleracea L.) and pea (Pisum sativum L.) were solubilized, fractionated by sucrose density gradient centrifugation, and analyzed by gel electrophoresis and crossed immunoelectrophoresis to identify the phosphoproteins. It was found that in addition to intense phosphorylation of light-harvesting chlorophyll complex II, four photosystem II components, CP43 apoprotein, D1, D2, and a 10 to 11 kilodalton protein, are substantially phosphorylated in the light. Furthermore, the CP43 apoprotein, D1 and D2 can be resolved into two electrophoretic subspecies, only one of which is phosphorylated. This indicates that only a fraction of the PSII polypeptides is phosphorylated. Finally, analysis of detergent procedures suggests that the 10 to 11 kilodalton phosphoprotein is a peripheral component of the O(2)-evolving PSII reaction center complex.
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PMID:Phosphorylation of Photosystem II Components, CP43 Apoprotein, D1, D2, and 10 to 11 Kilodalton Protein in Chloroplast Thylakoids of Higher Plants. 1666 52

Thylakoid-soluble phosphoprotein of 9 kDa, TSP9, is an intrinsically unstructured plant-specific protein [Song, J., et al. (2006) Biochemistry 45, 15633-15643] with unknown function but established associations with light-harvesting proteins and peripheries of both photosystems [Hansson, M., et al. (2007) J. Biol. Chem. 282, 16214-16222]. To investigate the function of this protein, we used a combination of reverse genetics and biochemical and fluorescence measurement methods in Arabidopsis thaliana. Differential gene expression analysis of plants with a T-DNA insertion in the TSP9 gene using an array of 24000 Arabidopsis genes revealed disappearance of high light-dependent induction of a specific set of mostly signaling and unknown proteins. TSP9-deficient plants had reduced levels of in vivo phosphorylation of light-harvesting complex II polypeptides. Recombinant TSP9 was phosphorylated in light by thylakoid membranes isolated from the wild-type and mutant plants lacking STN8 protein kinase but not by the thylakoids deficient in STN7 kinase, essential for photosynthetic state transitions. TSP9-lacking mutant and RNAi plants with downregulation of TSP9 showed reduced ability to perform state transitions. The nonphotochemical quenching of chlorophyll fluorescence at high light intensities was also less efficient in the mutant compared to wild-type plants. Blue native electrophoresis of thylakoid membrane protein complexes revealed that TSP9 deficiency increased relative stability of photosystem II dimers and supercomplexes. It is concluded that TSP9 regulates plant light harvesting acting as a membrane-binding protein facilitating dissociation of light-harvesting proteins from photosystem II.
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PMID:Intrinsically unstructured phosphoprotein TSP9 regulates light harvesting in Arabidopsis thaliana. 1911 38

The mycotoxin 3-nitropropionic acid (3NP) is an irreversible inhibitor that induces neuronal damage by inhibiting mitochondrial complex II. Neurodegeneration induced by 3NP, which is preferentially induced in the striatum, is caused by an excess influx and accumulation of calcium in mitochondria. Osteopontin (OPN) is a glycosylated phosphoprotein and plays a role in the regulation of calcium precipitation in the injured brain. The present study was designed to examine whether induction of OPN protein is implicated in the pathogenesis of 3NP-induced striatal neurodegeneration. We observed overlapping regional expression of OPN, the neurodegeneration marker Fluoro-Jade B, and the microglial marker ionized calcium-binding adaptor molecule 1 (Iba1) in the 3NP-lesioned striatum. OPN expression was closely associated with the mitochondrial marker NADH dehydrogenase (ubiquinone) flavoprotein 2 in the damaged striatum. In addition, immunoelectron microscopy demonstrated that OPN protein was specifically localized to the inner membrane and matrix of the mitochondria in degenerating striatal neurons, and cell fragments containing OPN-labeled mitochondria were also present within activated brain macrophages. Thus, our study revealed that OPN expression is associated with mitochondrial dysfunction produced by 3NP-induced alteration of mitochondrial calcium homeostasis, suggesting that OPN is involved in the pathogenesis of striatal degeneration by 3NP administration.
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PMID:Increased Expression of Osteopontin in the Degenerating Striatum of Rats Treated with Mitochondrial Toxin 3-Nitropropionic Acid: A Light and Electron Microscopy Study. 2663 5