Biochemistry (Moscow) (v.75, #12)
Estrogen receptors, antiestrogens, and non-small cell lung cancer by T. A. Bogush; E. A. Dudko; A. A. Beme; E. A. Bogush; A. I. Kim; B. E. Polotsky; S. A. Tjuljandin; M. I. Davydov (1421-1427).
This review considers data on expression of different types of estrogen receptors (ERα and ERβ) in in vitro cultured cells of non-small cell lung cancer and also in human and animal lung tumors. Estrogens are shown to play an important role in genesis and development of non-small cell lung cancer because the estrogen-stimulated cell proliferation as well as antiestrogen-caused inhibition of proliferation occurred only in the cells expressing different types of estrogen receptors. In general, the situation is similar to that observed in breast cancer, but in the cells of non-small cell lung cancer not ERα are expressed in more than half of cases but ERβ. Just estrogen receptors β play the crucial role in inducing cell proliferation in response to estrogens, and ERβ is a prognostic marker of a favorable course of non-small cell lung cancer. Data on the interactions between ER and EGFR signaling pathways, as well as on the additive antitumor effect of antiestrogens (tamoxifen and fulvestrant) combined with tyrosine kinase inhibitors (gefitinib, erlotinib, and vandetanib) are considered. The review also includes data on the influence of estrogens on genesis and development of lung cancer in humans and animals and the frequency of ERα and ERβ expression in non-small cell lung cancer in tissues from patients of the two sexes. Problems of quantitative determination of α and β estrogen receptors in the tumor cells are also discussed.
Keywords: estrogen receptors; non-small cell lung cancer; antiestrogens
The Wnt/Frizzled GPCR signaling pathway by V. L. Katanaev (1428-1434).
G protein-coupled receptors (GPCRs) represent the biggest transmembrane receptor family. The Frizzled group of GPCRs is evolutionarily conserved and serves to transduce signals from the Wnt-type lipoglycoprotein growth factors. The Wnt/Frizzled signaling cascades are repeatedly used during animal development and are mostly silent in the adult. Improper activation of these cascades, e.g. through somatic mutation, underlies cancer development in various tissues. Our research over the past years has identified the trimeric G proteins as crucial transducers of the Wnt/Frizzled cascades in insect and mammalian cells. The current mini-review summarizes our findings on the role of G proteins in Wnt/Frizzled signaling, as well as on identification of other signaling intermediates in this physiologically and pathologically important type of intracellular signal transduction.
Keywords: Wnt; Frizzled; G protein-coupled receptor; trimeric G proteins; development; carcinogenesis; morphogen
Cloning and characterization of indolepyruvate decarboxylase from Methylobacterium extorquens AM1 by D. N. Fedorov; N. V. Doronina; Yu. A. Trotsenko (1435-1443).
For the first time for methylotrophic bacteria an enzyme of phytohormone indole-3-acetic acid (IAA) biosynthesis, indole-3-pyruvate decarboxylase (EC 18.104.22.168), has been found. An open reading frame (ORF) was identified in the genome of facultative methylotroph Methylobacterium extorquens AM1 using BLAST. This ORF encodes thiamine diphosphate-dependent 2-keto acid decarboxylase and has similarity with indole-3-pyruvate decarboxylases, which are key enzymes of IAA biosynthesis. The ORF of the gene, named ipdC, was cloned into overexpression vector pET-22b(+). Recombinant enzyme IpdC was purified from Escherichia coli BL21(DE3) and characterized. The enzyme showed the highest k cat value for benzoylformate, albeit the indolepyruvate was decarboxylated with the highest catalytic efficiency (k cat/K m). The molecular mass of the holoenzyme determined using gel-permeation chromatography corresponds to a 245-kDa homotetramer. An ipdC-knockout mutant of M. extorquens grown in the presence of tryptophan had decreased IAA level (46% of wild type strain). Complementation of the mutation resulted in 6.3-fold increase of IAA concentration in the culture medium compared to that of the mutant strain. Thus involvement of IpdC in IAA biosynthesis in M. extorquens was shown.
Keywords: Methylobacterium extorquens ; indole-3-pyruvate decarboxylase; heterologous expression; kinetic properties; mutants
Novel inhibitors of glyceraldehyde-3-phosphate dehydrogenase: Covalent modification of NAD-binding site by aromatic thiols by K. A. Chernorizov; J. L. Elkina; P. I. Semenyuk; V. K. Švedas; V. I. Muronetz (1444-1449).
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 22.214.171.124) is a glycolytic enzyme catalyzing the formation of 1,3-diphosphoglycerate from glyceraldehyde-3-phosphate and inorganic phosphate. In cooperation with E3 ubiquitin-kinase Siah1, GAPDH directly participates in the apoptotic death of neurons in Parkinson’s disease. Potential GAPDH inhibitors were screened in silico, and three compounds with high affinity to the NAD-binding site and theoretically capable of forming a disulfide bond with amino acid residue Cys149 were found among cysteine and glutathione derivatives. The inhibitory effect of these compounds was tested on GAPDH from rabbit muscles using isothermal calorimetry and kinetic methods. As a result of experimental screening, we selected two compounds that inhibit GAPDH by forming disulfide bonds with the Cys149 residue in the enzyme active site. Since Cys149 is the key residue not only for the catalyzed reaction, but also for interaction with Siah1, the compounds can be assumed to inhibit the formation of the proapoptotic complex GAPDH-Siah1 and therefore have potential effect against Parkinson’s disease.
Keywords: glyceraldehyde-3-phosphate dehydrogenase; covalent inhibition; cysteine and glutathione derivatives; NAD-binding domain; apoptosis; Parkinson’s disease
Glycosylation of purified buffalo heart galectin-1 plays crucial role in maintaining its structural and functional integrity by G. M. Ashraf; N. Bilal; N. Suhail; S. Hasan; N. Banu (1450-1457).
A buffalo heart galectin-1 purified by gel filtration chromatography revealed the presence of 3.55% carbohydrate content, thus it is the first mammalian heart galectin found to be glycosylated in nature and emphasizes the need to perform deglycosylation studies. Physicochemical comparative analysis between the properties of the native and deglycosylated proteins was carried out to understand the significance of glycosylation. The deglycosylated protein exhibited lesser thermal and pH stability compared to the native galectin. When exposed to thiol blocking reagents, denaturants, and detergents, remarkable differences were observed in the properties of the native and deglycosylated protein. Compared to the native glycosylated protein, the deglycosylated galectin showed enhanced fluorescence quenching when exposed to various agents. CD and FTIR analysis showed that deglycosylation of the purified galectin and its exposure to different chemicals resulted in significant deviations from regular secondary structure of the protein, thus emphasizing the significance of glycosylation for maintaining the active conformation of the protein. The remarkable differences observed in the properties of the native and deglycosylated galectin add an important dimension to the significance of protein glycosylation and its associated biological and clinical relevance.
Keywords: buffalo heart galectin-1 (BfHG-1); glycosylation; deglycosylation; deglycosylated BfHG-1 (dBfHG-1); oxidation
Novel mutants of human tumor necrosis factor with dominant-negative properties by L. N. Shingarova; E. F. Boldyreva; S. A. Yakimov; S. V. Guryanova; D. A. Dolgikh; S. A. Nedospasov; M. P. Kirpichnikov (1458-1463).
Tumor necrosis factor (TNF) is a polyfunctional cytokine, one of the key mediators of inflammation and innate immunity. On the other hand, systemic or local TNF overexpression is typical of such pathological states as rheumatoid arthritis, psoriasis, Crohn’s disease, septic shock, and multiple sclerosis. Neutralization of TNF activity has a marked curative effect for some diseases; therefore, the search for various TNF blockers is a promising field of protein engineering and biotechnology. According to the previously developed concept concerning the possibility of designing dominant-negative mutants, the following TNF variants have been studied: TNFY87H + A145R, TNFY87H + A96S + A145R, and TNFV91N + A145R. All of these form inactive TNF heterotrimers with the native protein. The ability of mutants to neutralize the effect of TNF was investigated. The addition of mutants to the native protein was shown to provide a concentration-dependent suppression of TNF cytotoxicity against the mouse fibroblast cell line L929. Thus, novel inhibitors of human TNF can be engineered on the basis of these muteins.
Keywords: tumor necrosis factor (TNF); mutants; TNF inhibitors
Interaction of ceruloplasmin and 5-lipoxygenase by A. V. Sokolov; E. A. Golenkina; V. A. Kostevich; V. B. Vasilyev; G. F. Sud’ina (1464-1469).
The interaction between ceruloplasmin (CP), the multicopper oxidase of human plasma, and 5-lipoxygenase (5-LO), the key enzyme of leukotriene synthesis, is shown for the first time. By Western-blotting and mass spectrometry of tryptic fragments, it is shown that 5-LO from protein extract of human leukocytes binds with immobilized CP. Dose-dependent influence of intact CP on leukotrienes synthesis is found: CP reduced leukotrienes synthesis in leukocytes in a dose above 50 μg/ml (normal CP concentration in plasma is about 300–400 μg/ml). Proteolyzed CP and apo-form of CP is unable to inhibit activity of 5-LO. CP increased activity of 5-LO at low doses (5–10 μg/ml). On the whole, the influence of CP on phagocytosis index of leukocytes coordinates with influence on activity of 5-LO: the index increased in the range of 2–10 μg/ml CP and decreased at doses of CP above 40 μg/ml. The dual role of CP in regulation of cellular response of leukocytes is discussed.
Keywords: protein-protein interaction; inflammation; leukotrienes; 5-lipoxygenase; ceruloplasmin
Proteome analysis of chloroplasts from the moss Physcomitrella patens (Hedw.) B.S.G. by N. B. Polyakov; D. K. Slizhikova; M. Yu. Izmalkova; N. I. Cherepanova; V. S. Kazakov; M. A. Rogova; N. A. Zhukova; D. G. Alexeev; N. A. Bazaleev; A. Yu. Skripnikov; V. M. Govorun (1470-1483).
Intact chloroplasts were prepared from protoplasts of the moss Physcomitrella patens according to an especially developed method. They were additionally separated into stroma and thylakoid fractions. The proteomes of intact plastids, stroma, and thylakoids were analyzed by 1D-electrophoresis under denaturing conditions followed by protein digestion and nano-LC-ESI-MS/MS of tryptic peptides from gel bands. A total of 624 unique proteins were identified, 434 of which were annotated as chloroplast resident proteins. The majority of proteins belonged to a photosynthetic group (21.3%) and to the group of proteins implicated in protein degradation, posttranslational modification, folding, and import (20.6%). Among proteins assigned to chloroplasts, the following groups are prominent combining proteins implicated in metabolism of: amino acids (6.9%), nucleotides (2.5%), lipids (2.2%), carbohydrates (2.4%), hormones (1.5%), isoprenoids (1.25%), vitamins and cofactors (1%), sulfur (1.25%), and nitrogen (1%); as well as proteins involved in the pentose-phosphate cycle (1.75%), tetrapyrrole synthesis (3.7%), and redox processes (3.6%). The data can be used in physiological and photobiological studies as well as in further studies of P. patens chloroplast proteome including structural and functional specifics of plant protein localization in organelles.
Keywords: proteome; chloroplast; Physcomitrella patens ; photosynthesis; subcellular localization
Recombinant DNA-methyltransferase M1.BspACI from Bacillus psychrodurans AC: Purification and properties by M. V. Tarasova; V. V. Kuznetsov; N. A. Netesova; D. A. Gonchar; S. Kh. Degtyarev (1484-1490).
A restriction-modification system from Bacillus psychrodurans AC (recognition sequence 5′-CCGC-3′) comprises two DNA methyltransferases: M1.BspACI and M2.BspACI. The bspACIM1 gene was cloned in the pJW2 vector and expressed in Escherichia coli cells. High-purity M1.BspACI preparation has been obtained by chromatography on different carriers. M1.BspACI has a temperature optimum of 30°C and demonstrates maximum activity at pH 8.0. M1.BspACI modifies the first cytosine in the recognition sequence 5′-CCGC-3′. The kinetic parameters of M1.BspACI DNA methylation are as follows: K m for phage λ DNA is 0.053 μM and K m for S-adenosyl-L-methionine is 5.1 μM. The catalytic constant (k cat) is 0.095 min−1.
Keywords: DNA methyltransferase; Bacillus psychrodurans ; enzyme kinetics
Dietary supplementation of old rats with hydrogenated peanut oil restores activities of mitochondrial respiratory complexes in skeletal muscles by G. E. Bronnikov; T. P. Kulagina; A. V. Aripovsky (1491-1497).
The effect of dietary supplementation of old rats (26–33 months) with hydrogenated peanut oil on the activity of mitochondrial enzymes in skeletal muscles has been studied. The activities of NADH-coenzyme Q1 oxidoreductase, cytochrome c oxidase, and citrate synthase were determined spectrophotometrically in muscle homogenates. The activities of respiratory complexes I and IV were shown to significantly decrease with the age compared to the activity of the same enzymes in young animals, while the activity of citrate synthase was virtually unchanged. The fatty acid composition of muscle homogenates of old rats differed from that of young animals by a reduced content of myristic, oleic, linoleic, and α-linolenic acids and enhanced content of dihomo-γ-linolenic, arachidonic, and docosahexaenoic acids. Per oral supple-mentation of the old rats with hydrogenated peanut oil completely restored the activity of complex IV and increased the activity of complex I to 80% of the value observed in muscles of young animals, reducing the content of stearic, dihomo-γ-linolenic, arachidonic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids relative to that in the groups of old and young rats. The content of oleic and linoleic acids increased relatively to that in the group of the old rats, as well as young animals. The possible mechanisms of the restoration of the activity of the respiratory enzymes under the administration of hydrogenated peanut oil are discussed.
Keywords: mitochondrial respiratory chain; oxidative stress; aging; fatty acid composition of lipids; skeletal muscles; vegetable oil
Discovery of a photosynthesizing animal that can survive for months in a light-dependent manner by V. P. Skulachev (1498-1499).
Recently M. E. Rumpho and coworkers (USA) established that the marine slug Elysia chlorotica, a gastropod mollusk that feeds on the eukaryotic filamentous yellow-green alga Vaucheria litorea, recruits chloroplasts from the alga and transports them from the digestive apparatus into a special organ of the slug that resembles a green leaf and is an approximately 100-fold increased parapodium—an outgrowth of the slug’s body. The chloroplasts survive inside the slug for up to 10 months and perform active photosynthesis accompanied by assimilation of CO2. Under conditions of starvation, this photosynthesis becomes for the animal the only source of energy and fixed carbon. For functioning, chloroplasts have to constantly import some short-lived proteins that are encoded in the nucleus of the photosynthesizing organism. Therefore, the authors supposed that a transfer of the corresponding genes must have occurred between the algal and mollusk nuclei. This hypothesis was experimentally confirmed for two genes encoding proteins of the photosynthesizing apparatus. The questions arise of what mechanism was responsible for the transfer of these genes and how the slug created its photosynthesizing organ resembling the leaf of a higher plant rather than the primitive filamentous algal structure which was the source of the acquired chloroplasts and the photosynthesis genes.
Keywords: photosynthesis; animal; mollusk; chloroplast