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Lukman S, Robinson RC, Wales D, Verma CS. Conformational dynamics of capping protein and interaction partners: Simulation studies. Proteins 2012; 80:1066-77. [DOI: 10.1002/prot.24008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 11/11/2011] [Accepted: 11/18/2011] [Indexed: 11/09/2022]
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Harvey AJ, Kind KL, Thompson JG. Regulation of gene expression in bovine blastocysts in response to oxygen and the iron chelator desferrioxamine. Biol Reprod 2007; 77:93-101. [PMID: 17329595 DOI: 10.1095/biolreprod.106.058826] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Low (2%) oxygen conditions during postcompaction culture of bovine blastocysts improve embryo quality and are associated with small increases in the expression of glucose transporter 1 (SLC2A1), anaphase promoting complex (ANAPC1), and myotrophin (MTPN), suggesting a role for oxygen in the regulation of embryo development, mediated through oxygen-sensitive gene expression. However, bovine embryos, to at least the blastocyst stage, lack detectable levels of the key regulator of oxygen-sensitive gene expression, hypoxia-inducible 1 alpha (HIF1A), while the less well-characterized HIF2 alpha protein is readily detectable. Here we report that other key HIF1 regulated genes are not significantly altered in their expression pattern in bovine blastocysts in response to reduced oxygen concentrations postcompaction-with the exception of lactate dehydrogenase A (LDHA), which was significantly increased following 2% oxygen culture. Antioxidant enzymes have been suggested as potential HIF2 target genes, but their expression was not altered following low-oxygen culture in the bovine blastocyst. The addition of desferrioxamine (an iron chelator and inducer of HIF-regulated gene expression) during postcompaction stages significantly increased SLC2A1, LDHA, inducible nitric oxide synthase (NOS2A), and MTPN gene expression in bovine blastocysts, although development to the blastocyst stage was not significantly affected. These results further suggest that expression of genes, known to be regulated by oxygen via HIF-1 in somatic cells, is not influenced by oxygen during preimplantation postcompaction bovine embryo development. Oxygen-regulated expression of LDHA and SLC2A1 in bovine blastocysts suggests that regulation of these genes may be mediated by HIF2. Furthermore, the effect of a reduced-oxygen environment on gene expression can be mimicked in vitro through the use of desferrioxamine. These results further support our data that the bovine blastocyst stage embryo is unique in its responsiveness to oxygen compared with somatic cells, in that the lack of HIF1-mediated gene expression reduces the overall response to low (physiological) oxygen environments, which appear to favor development.
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Affiliation(s)
- A J Harvey
- Research Centre for Reproductive Health, Discipline of Obstetrics and Gynecology, Medical School, The University of Adelaide, Adelaide, South Australia 5005, Australia.
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Harvey AJ, Navarrete Santos A, Kirstein M, Kind KL, Fischer B, Thompson JG. Differential expression of oxygen-regulated genes in bovine blastocysts. Mol Reprod Dev 2007; 74:290-9. [PMID: 16998843 DOI: 10.1002/mrd.20617] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Low oxygen conditions (2%) during post-compaction culture of bovine blastocysts improve embryo quality, which is associated with a small yet significant increase in the expression of glucose transporter 1 (GLUT-1), suggesting a role of oxygen in embryo development mediated through oxygen-sensitive gene expression. However, bovine embryos to at least the blastocyst stage lack a key regulator of oxygen-sensitive gene expression, hypoxia-inducible factor 1alpha (HIF1alpha). A second, less well-characterized protein (HIF2alpha) is, however, detectable from the 8-cell stage of development. Here we use differential display to determine additional gene targets in bovine embryos in response to low oxygen conditions. While development to the blastocyst stage was unaffected by the oxygen concentration used during post-compaction culture, differential display identified oxygen-regulation of myotrophin and anaphase promoting complex 1 expression, with significantly lower levels observed following culture under 20% oxygen than 2% oxygen. These results further support the hypothesis that the level of gene expression of specific transcripts by bovine embryos alters in response to changes in the oxygen environment post-compaction. Specifically, we have identified two oxygen-sensitive genes that are potentially regulated by HIF2 in the bovine blastocyst.
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Affiliation(s)
- A J Harvey
- Research Centre for Reproductive Health, Department of Obstetrics and Gynaecology, The University of Adelaide, The Queen Elizabeth Hospital, Woodville, South Australia, Australia.
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Bhattacharya N, Ghosh S, Sept D, Cooper JA. Binding of myotrophin/V-1 to actin-capping protein: implications for how capping protein binds to the filament barbed end. J Biol Chem 2006; 281:31021-30. [PMID: 16895918 PMCID: PMC2277501 DOI: 10.1074/jbc.m606278200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The heterodimeric actin-capping protein (CP) regulates actin assembly and cell motility by binding tightly to the barbed end of the actin filament. Here we demonstrate that myotrophin/V-1 binds directly to CP in a 1:1 molar ratio with a Kd of 10-50 nm. V-1 binding inhibited the ability of CP to cap the barbed ends of actin filaments. The actin-binding COOH-terminal region, the "tentacle," of the CP beta subunit was important for binding V-1, with lesser contributions from the alpha subunit COOH-terminal region and the body of the protein. V-1 appears to be unable to bind to CP that is on the barbed end, based on the observations that V-1 had no activity in an uncapping assay and that the V-1.CP complex had no capping activity. Two loops of V-1, which extend out from the alpha-helical backbone of this ankyrin repeat protein, were necessary for V-1 to bind CP. Parallel computational studies determined a bound conformation of the beta tentacle with V-1 that is consistent with these findings, and they offered insight into experimentally observed differences between the alpha1 and alpha2 isoforms as well as the mutant lacking the alpha tentacle. These results support and extend our "wobble" model for CP binding to the actin filament, in which the two COOH-terminal regions of CP bind independently to the actin filament, and bound CP is able to wobble when attached only via its mobile beta-subunit tentacle. This model is also supported by molecular dynamics simulations of CP reported here. The existence of the wobble state may be important for actin dynamics in cells.
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Affiliation(s)
- Nandini Bhattacharya
- Department of Cell Biology and Physiology, Washington University, St. Louis, Missouri 63110
| | - Shatadal Ghosh
- Department of Biomedical Engineering and Center for Computational Biology, Washington University, St. Louis, Missouri 63110
| | - David Sept
- Department of Biomedical Engineering and Center for Computational Biology, Washington University, St. Louis, Missouri 63110
| | - John A. Cooper
- Department of Cell Biology and Physiology, Washington University, St. Louis, Missouri 63110
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Kitazawa M, Yamakuni T, Song SY, Kato C, Tsuchiya R, Ishida M, Suzuki N, Adachi E, Iwashita S, Ueno S, Yanagihara N, Taoka M, Isobe T, Ohizumi Y. Intracellular cAMP controls a physical association of V-1 with CapZ in cultured mammalian endocrine cells. Biochem Biophys Res Commun 2005; 331:181-6. [PMID: 15845376 DOI: 10.1016/j.bbrc.2005.03.127] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2005] [Indexed: 10/25/2022]
Abstract
V-1, an ankyrin repeat protein with the activity to control tyrosine hydroxylase (TH) gene expression and transmitter release in PC12D cells, associates with CapZ, an actin capping protein, and thereby regulates actin polymerization in vitro. In this study, immunoprecipitation and Western blot analysis showed that V-1 was physically associated with CapZ-beta in PC12D transfectants overexpressing V-1. These proteins were co-localized in the soma of Purkinje cells of rat cerebellum as assayed by immunohistochemistry. Furthermore, in the V-1 transfectants, the amount of CapZ which physically associated with V-1 was steeply reduced at 2h after treatment with forskolin, but was thereafter increased to reach its initial level at 12h after forskolin-treatment. These results suggest that the association of V-1 with CapZ is controlled by a cAMP-dependent signalling pathway probably to play a functional role in the regulatory mechanism of actin dynamics in the endocrine system and the central nervous system.
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Affiliation(s)
- Masashi Kitazawa
- Department of Pharmaceutical Molecular Biology, Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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Yamakuni T, Hashimoto M, Sakagami H, Yamamoto T, Kobayashi M, Fujii Y, Yamamoto H, Rohra DK, Hiwatashi Y, Honma T, Kondo H, Shido O, Ohizumi Y. Expression of V-1, a novel catecholamine biosynthesis regulatory protein, is enhanced by hypertension in atrial myocytes of Dahl salt-sensitive rats. Biochem Biophys Res Commun 2002; 298:793-7. [PMID: 12419325 DOI: 10.1016/s0006-291x(02)02529-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
V-1 positively controls catecholamine synthetic gene transcription to promote catecholamine production in PC12D cells. In this study, immunohistochemical analysis revealed that in Wistar rats, V-1 immunoreactivity was localized not only in sympathetic axons but also in the cytoplasm of cardiomyocytes, and that the immunoreactivity in atrial myocytes was more intense than that in ventricular myocytes. Western blot analysis also showed that V-1 expression level in the atrium was higher than that in the ventricle of Wistar rat hearts. When Dahl salt-sensitive (DS) rats were fed an 8% NaCl diet after the age of 6 weeks, blood pressure was raised 230mm Hg at 18 weeks. V-1 expression was shown to be increased in the atrial myocytes of these DS rats, but not in the sympathetic axons, when assayed by immunohistochemistry. These results suggest that in normotensive rats, V-1 is preferentially expressed in the cytoplasm of cardiomyocytes in the atrium rather than in the ventricle. It is also suggested that V-1 expression is increased by hypertension in DS rat atrium.
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Affiliation(s)
- Tohru Yamakuni
- Department of Pharmaceutical Molecular Biology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan.
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Knuefermann P, Chen P, Misra A, Shi SP, Abdellatif M, Sivasubramanian N. Myotrophin/V-1, a protein up-regulated in the failing human heart and in postnatal cerebellum, converts NFkappa B p50-p65 heterodimers to p50-p50 and p65-p65 homodimers. J Biol Chem 2002; 277:23888-97. [PMID: 11971907 DOI: 10.1074/jbc.m202937200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myotrophin/V-1 is a cytosolic protein found at elevated levels in failing human hearts and in postnatal cerebellum. We have previously shown that it disrupts nuclear factor of kappaB (NFkappaB)-DNA complexes in vitro. In this study, we demonstrated that in HeLa cells native myotrophin/V-1 is predominantly present in the cytoplasm and translocates to the nucleus during sustained NFkappaB activation. Three-dimensional alignment studies indicate that myotrophin/V-1 resembles a truncated IkappaBalpha without the signal response domain (SRD) and PEST domains. Co-immunoprecipitation studies reveal that myotrophin/V-1 interacts with NFkappaB proteins in vitro; however, it remains physically associated only with p65 and c-Rel proteins in vivo during NFkappaB activation. In vitro studies indicate that myotrophin/V-1 can promote the formation of p50-p50 homodimers from monomeric p50 proteins and can convert the preformed p50-p65 heterodimers into p50-p50 and p65-p65 homodimers. Furthermore, adenovirus-mediated overexpression of myotrophin/V-1 resulted in elevated levels of both p50-p50 and p65-p65 homodimers exceeding the levels of p50-p65 heterodimers compared with Adbetagal-infected cells, where the levels of p50-p65 heterodimers exceeded the levels of p50-p50 and p65-p65 homodimers. Thus, overexpression of myotrophin/V-1 during NFkappaB activation resulted in a qualitative shift by quantitatively reducing the level of transactivating heterodimers while elevating the levels of repressive p50-p50 homodimers. Correspondingly, overexpression of myotrophin/V-1 resulted in significantly reduced kappaB-luciferase reporter activity. Because myotrophin/V-1 is found at elevated levels during NFkappaB activation in postnatal cerebellum and in failing human hearts, this study cumulatively suggests that myotrophin/V-1 is a regulatory protein for modulating the levels of activated NFkappaB dimers during this period.
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Affiliation(s)
- Pascal Knuefermann
- Winters Center For Heart Failure Research, Molecular Cardiology Unit, Cardiology Section of Department of Medicine, Baylor College of Medicine, Veterans Affairs Medical Center, Houston, Texas 77030, USA
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Kaji H, Tsuji T, Mawuenyega KG, Wakamiya A, Taoka M, Isobe T. Profiling of Caenorhabditis elegans proteins using two-dimensional gel electrophoresis and matrix assisted laser desorption/ionization-time of flight-mass spectrometry. Electrophoresis 2000; 21:1755-65. [PMID: 10870962 DOI: 10.1002/(sici)1522-2683(20000501)21:9<1755::aid-elps1755>3.0.co;2-s] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The nematode Caenorhabditis elegans (C. elegans) is the first animal whose whole 97 Mb genome sequence, encoding ca. 19000 open reading frames (ORF's), has been essentially determined. We tried to establish a 2-DE map of the nematode proteome by means of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). A soluble protein fraction of mixed stages of the worm, wild-type strain N2, was applied to 2-D PAGE. After Coomassie Brilliant Blue (CBB) staining, 1200 spots were detected and 140 major spots were excised from the gel and subjected to in-gel digestion with Achromobacter protease I (lysyl endopeptidase). Resulting peptides were analyzed by matrix assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) followed by peptide mass fingerprinting for protein identification. With this approach we have obtained a two-dimensional electrophoresis (2-DE) protein map in which 69 spots were localized as landmarks for comparison of expression profiles to elucidate the basis of various biological events.
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Affiliation(s)
- H Kaji
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Japan.
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Yamakuni T, Yamamoto T, Hoshino M, Song SY, Yamamoto H, Kunikata-Sumitomo M, Minegishi A, Kubota M, Ito M, Konishi S. A novel protein containing Cdc10/SWI6 motifs regulates expression of mRNA encoding catecholamine biosynthesizing enzymes. J Biol Chem 1998; 273:27051-4. [PMID: 9765218 DOI: 10.1074/jbc.273.42.27051] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Catecholaminergic (dopaminergic, noradrenergic, and adrenergic) transmitter phenotypes require the cooperative actions of four biosynthetic enzymes: tyrosine hydroxylase, aromatic L-amino acid decarboxylase, dopamine beta-hydroxylase, and phenylethanolamine N-methyltransferase. Mechanisms that control expression of these enzymes in a transmitter phenotype-specific manner, however, are poorly understood. Here, we provide evidence that overexpression of a novel cdc10/SWI6 motif-containing protein, V-1, elicits the coordinate up-regulation of tyrosine hydroxylase, aromatic L-amino acid decarboxylase, and dopamine beta-hydroxylase mRNAs in the neuronal cell line PC12D, and as a result, catecholamine levels are increased. Furthermore, V-1 is strongly expressed in the cytoplasm of rat chromaffin cells of adrenal medulla. Thus, V-1 may act as a cytoplasmic protein/protein adapter and be involved in control of the catecholaminergic phenotype expression via an intracellular pathway signaling to the nucleus.
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Affiliation(s)
- T Yamakuni
- Mitsubishi Kasei Institute of Life Sciences, 11 Minamiooya, Machida, Tokyo 194-8511, Japan.
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