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Auswahl der wissenschaftlichen Literatur zum Thema „Myosine-X“
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Zeitschriftenartikel zum Thema "Myosine-X"
1
Berg, J. S., B. H. Derfler, C. M. Pennisi, D. P. Corey und R. E. Cheney. „Myosin-X, a novel myosin with pleckstrin homology domains, associates with regions of dynamic actin“. Journal of Cell Science 113, Nr. 19 (01.10.2000): 3439–51. http://dx.doi.org/10.1242/jcs.113.19.3439.
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Myosin-X is the founding member of a novel class of unconventional myosins characterized by a tail domain containing multiple pleckstrin homology domains. We report here the full-length cDNA sequences of human and bovine myosin-X as well as the first characterization of this protein's distribution and biochemical properties. The 235 kDa myosin-X contains a head domain with <45% protein sequence identity to other myosins, three IQ motifs, and a predicted stalk of coiled coil. Like several other unconventional myosins and a plant kinesin, myosin-X contains both a myosin tail homology 4 (MyTH4) domain and a FERM (band 4.1/ezrin/radixin/moesin) domain. The unique tail domain also includes three pleckstrin homology domains, which have been implicated in phosphatidylinositol phospholipid signaling, and three PEST sites, which may allow cleavage of the myosin tail. Most intriguingly, myosin-X in cultured cells is present at the edges of lamellipodia, membrane ruffles, and the tips of filopodial actin bundles. The tail domain structure, biochemical features, and localization of myosin-X suggest that this novel unconventional myosin plays a role in regions of dynamic actin.
2
Novakovic, Valerie A., und Gary E. Gilbert. „Procoagulant activities of skeletal and cardiac muscle myosin depend on contaminating phospholipid“. Blood 136, Nr. 21 (19.11.2020): 2469–72. http://dx.doi.org/10.1182/blood.2020005930.
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Abstract Recent reports indicate that suspended skeletal and cardiac myosin, such as might be released during injury, can act as procoagulants by providing membrane-like support for factors Xa and Va in the prothrombinase complex. Further, skeletal myosin provides membrane-like support for activated protein C. This raises the question of whether purified muscle myosins retain procoagulant phospholipid through purification. We found that lactadherin, a phosphatidyl-l-serine–binding protein, blocked >99% of prothrombinase activity supported by rabbit skeletal and by bovine cardiac myosin. Similarly, annexin A5 and phospholipase A2 blocked >95% of myosin-supported activity, confirming that contaminating phospholipid is required to support myosin-related prothrombinase activity. We asked whether contaminating phospholipid in myosin preparations may also contain tissue factor (TF). Skeletal myosin supported factor VIIa cleavage of factor X equivalent to contamination by ∼1:100 000 TF/myosin, whereas cardiac myosin had TF-like activity >10-fold higher. TF pathway inhibitor inhibited the TF-like activity similar to control TF. These results indicate that purified skeletal muscle and cardiac myosins support the prothrombinase complex indirectly through contaminating phospholipid and also support factor X activation through TF-like activity. Our findings suggest a previously unstudied affinity of skeletal and cardiac myosin for phospholipid membranes.
3
Rogers, Michael S., und Emanuel E. Strehler. „The Tumor-sensitive Calmodulin-like Protein Is a Specific Light Chain of Human Unconventional Myosin X“. Journal of Biological Chemistry 276, Nr. 15 (22.01.2001): 12182–89. http://dx.doi.org/10.1074/jbc.m010056200.
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Human calmodulin-like protein (CLP) is an epithelial-specific Ca2+-binding protein whose expression is strongly down-regulated in cancers. Like calmodulin, CLP is thought to regulate cellular processes via Ca2+-dependent interactions with specific target proteins. Using gel overlays, we identified a ∼210-kDa protein binding specifically and in a Ca2+-dependent manner to CLP, but not to calmodulin. Yeast two-hybrid screening yielded a CLP-interacting clone encoding the three light chain binding IQ motifs of human “unconventional” myosin X. Pull-down experiments showed CLP binding to the IQ domain to be direct and Ca2+-dependent. CLP interacted strongly with IQ motif 3 (Kd∼0.5 nm) as determined by surface plasmon resonance. Epitope-tagged myosin X was localized preferentially at the cell periphery in MCF-7 cells, and CLP colocalized with myosin X in these cells. Myosin X was able to coprecipitate CLP and, to a lesser extent, calmodulin from transfected COS-1 cells, indicating that CLP is a specific light chain of myosin Xin vivo. Because unconventional myosins participate in cellular processes ranging from membrane trafficking to signaling and cell motility, myosin X is an attractive CLP target. Altered myosin X regulation in (tumor) cells lacking CLP may have as yet unknown consequences for cell growth and differentiation.
4
Naydenov, Nayden, Susana Lechuga, Emina Huang und Andrei Ivanov. „Myosin Motors: Novel Regulators and Therapeutic Targets in Colorectal Cancer“. Cancers 13, Nr. 4 (11.02.2021): 741. http://dx.doi.org/10.3390/cancers13040741.
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Colorectal cancer (CRC) remains the third most common cause of cancer and the second most common cause of cancer deaths worldwide. Clinicians are largely faced with advanced and metastatic disease for which few interventions are available. One poorly understood aspect of CRC involves altered organization of the actin cytoskeleton, especially at the metastatic stage of the disease. Myosin motors are crucial regulators of actin cytoskeletal architecture and remodeling. They act as mechanosensors of the tumor environments and control key cellular processes linked to oncogenesis, including cell division, extracellular matrix adhesion and tissue invasion. Different myosins play either oncogenic or tumor suppressor roles in breast, lung and prostate cancer; however, little is known about their functions in CRC. This review focuses on the functional roles of myosins in colon cancer development. We discuss the most studied class of myosins, class II (conventional) myosins, as well as several classes (I, V, VI, X and XVIII) of unconventional myosins that have been linked to CRC development. Altered expression and mutations of these motors in clinical tumor samples and their roles in CRC growth and metastasis are described. We also evaluate the potential of using small molecular modulators of myosin activity to develop novel anticancer therapies.
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Brown, Lisa D., und Marie E. Cantino. „Immunocytochemical Localization of Myosin Light Chains in the Abdominal Superficial Flexor Muscles of the American Lobster, Homarus Americanus“. Microscopy and Microanalysis 4, S2 (Juli 1998): 1118–19. http://dx.doi.org/10.1017/s143192760002571x.
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Myosin is composed of two high-molecular weight heavy chains and four low-molecular weight hght chains. In both vertebrate and invertebrate skeletal muscle, each myosin heavy chain is associated with two myosin light chains. In skeletal muscle myosins studied by X-ray diffraction, each myosin heavy chain binds one of each of two distinct classes of hght chains. Thus, while isoform distributions may vary within and between fibers, the spatial distribution of each class of light chain should be uniform within the A band and between sarcomeres and fibers. Since no such study exists for crustacean myosin, we investigated the spatial distribution of the hght chains within the superficial flexor muscle (SFM) of the lobster, Homarus americanus, using immunoelectron microscopy. The SFM contains two classes of myosin hght chains, termed “alpha” (Mr = 21,000 to 23,500) and “beta” (Mr = 18,000 to 18,500). Immunocytochemical electron microscopic results suggest that the alpha light chains are not uniformly distributed at the subsarcomere level.
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Squire, John. „Special Issue: The Actin-Myosin Interaction in Muscle: Background and Overview“. International Journal of Molecular Sciences 20, Nr. 22 (14.11.2019): 5715. http://dx.doi.org/10.3390/ijms20225715.
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Muscular contraction is a fundamental phenomenon in all animals; without it life as we know it would be impossible. The basic mechanism in muscle, including heart muscle, involves the interaction of the protein filaments myosin and actin. Motility in all cells is also partly based on similar interactions of actin filaments with non-muscle myosins. Early studies of muscle contraction have informed later studies of these cellular actin-myosin systems. In muscles, projections on the myosin filaments, the so-called myosin heads or cross-bridges, interact with the nearby actin filaments and, in a mechanism powered by ATP-hydrolysis, they move the actin filaments past them in a kind of cyclic rowing action to produce the macroscopic muscular movements of which we are all aware. In this special issue the papers and reviews address different aspects of the actin-myosin interaction in muscle as studied by a plethora of complementary techniques. The present overview provides a brief and elementary introduction to muscle structure and function and the techniques used to study it. It goes on to give more detailed descriptions of what is known about muscle components and the cross-bridge cycle using structural biology techniques, particularly protein crystallography, electron microscopy and X-ray diffraction. It then has a quick look at muscle mechanics and it summarises what can be learnt about how muscle works based on the other studies covered in the different papers in the special issue. A picture emerges of the main molecular steps involved in the force-producing process; steps that are also likely to be seen in non-muscle myosin interactions with cellular actin filaments. Finally, the remarkable advances made in studying the effects of mutations in the contractile assembly in causing specific muscle diseases, particularly those in heart muscle, are outlined and discussed.
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Courson, David S., und Richard E. Cheney. „Myosin-X and disease“. Experimental Cell Research 334, Nr. 1 (Mai 2015): 10–15. http://dx.doi.org/10.1016/j.yexcr.2015.03.014.
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Dillmann, W. H. „Methyl palmoxirate increases Ca2+-myosin ATPase activity and changes myosin isoenzyme distribution in the diabetic rat heart“. American Journal of Physiology-Endocrinology and Metabolism 248, Nr. 5 (01.05.1985): E602—E606. http://dx.doi.org/10.1152/ajpendo.1985.248.5.e602.
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Previous studies have shown that in rats diabetes mellitus leads to a decrease in cardiac ventricle myosin V1 and an increase in myosin V3 levels. Insulin administration reverts myosin isoenzyme distribution to normal levels. It is currently unclear whether the effects of insulin on myosin isoenzyme distribution are a direct effect of the hormone or are mediated through insulin-induced alterations in cardiac metabolism. To gain further insight into this question diabetic rats received methyl palmoxirate, a potent inhibitor of long-chain fatty acid oxidation. Administration of 25 mg methyl palmoxirate X kg body wt-1 X day-1 to diabetic rats for 4 wk leads to a partial reversal of the effects of diabetes. Myosin V1 predominance is re-established and Ca2+-activated myosin ATPase activity increases by 60% (Ca2+-myosin ATPase normal rats 1.067 +/- 0.13 mumol Pi X mg protein-1 X min-1, diabetic rats 0.609 +/- 0.05 mumol Pi X mg protein-1 X min-1, diabetic + methyl palmoxirate rats 0.912 +/- 0.06 mumol Pi X mg protein-1 X min-1). The methyl palmoxirate-induced increase in myosin V1 levels and Ca2+-activated myosin ATPase activity occurred in the absence of changes in insulin and thyroid hormone levels. Methyl palmoxirate may have acted through its known inhibitory effect on cardiac beta-oxidation and/or the resultant stimulatory effect on glycolytic flux. Our findings may indicate that changes in cardiac substrate consumption can influence myosin isoenzyme predominance.
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Almagro, Sébastien, Claire Durmort, Adeline Chervin-Pétinot, Stephanie Heyraud, Mathilde Dubois, Olivier Lambert, Camille Maillefaud et al. „The Motor Protein Myosin-X Transports VE-Cadherin along Filopodia To Allow the Formation of Early Endothelial Cell-Cell Contacts“. Molecular and Cellular Biology 30, Nr. 7 (01.02.2010): 1703–17. http://dx.doi.org/10.1128/mcb.01226-09.
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ABSTRACT Vascular endothelium (VE), the monolayer of endothelial cells that lines the vascular tree, undergoes damage at the basis of some vascular diseases. Its integrity is maintained by VE-cadherin, an adhesive receptor localized at cell-cell junctions. Here, we show that VE-cadherin is also located at the tip and along filopodia in sparse or subconfluent endothelial cells. We observed that VE-cadherin navigates along intrafilopodial actin filaments. We found that the actin motor protein myosin-X is colocalized and moves synchronously with filopodial VE-cadherin. Immunoprecipitation and pulldown assays confirmed that myosin-X is directly associated with the VE-cadherin complex. Furthermore, expression of a dominant-negative mutant of myosin-X revealed that myosin-X is required for VE-cadherin export to cell edges and filopodia. These features indicate that myosin-X establishes a link between the actin cytoskeleton and VE-cadherin, thereby allowing VE-cadherin transportation along intrafilopodial actin cables. In conclusion, we propose that VE-cadherin trafficking along filopodia using myosin-X motor protein is a prerequisite for cell-cell junction formation. This mechanism may have functional consequences for endothelium repair in pathological settings.
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Ikebe, Mitsuo, Osamu Sato und Tsuyoshi Sakai. „Myosin X and Cytoskeletal Reorganization“. Applied Microscopy 48, Nr. 2 (30.06.2018): 33–42. http://dx.doi.org/10.9729/am.2018.48.2.33.
Der volle Inhalt der QuelleDissertationen zum Thema "Myosine-X"
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Crozet, Flora. „Somatic cells enhance the oocyte developmental potential through cytoplasmic protrusions“. Electronic Thesis or Diss., Sorbonne université, 2021. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2021SORUS166.pdf.
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Chez les femelles mammifères, les cellules somatiques qui entourent l’ovocyte, les cellules de la granulosa, coordonnent le développement ovocytaire post-partum, la croissance ovocytaire et la maturation méiotique, en dialoguant avec l’ovocyte. Ce dialogue est principalement établi par contact intercellulaire grâce à des protrusions des cellules de la granulosa, les projections transzonales (TZPs). Les TZPs ressemblent à des filopodes, résident dans la matrice extracellulaire entourant l’ovocyte, la zone pellucide, et établissent des jonctions gap et d’adhérence avec la membrane de l’ovocyte. Durant ma thèse, j’ai étudié le rôle des TZPs dans le développement ovocytaire. En générant un knockout total de la Myosine-X chez la souris, une protéine contenue dans les TZPs et participant à la formation des filopodes, nous avons obtenu des ovocytes avec une densité de TZPs réduite. Cela n’empêche pas l’ovocyte d’atteindre une taille canonique. Cependant, cela altère l’intégrité de la zone pellucide, l’adhésion ovocyte-matrice extracellulaire, et le transcriptome de l’ovocyte en fin de croissance, les transcrits dérégulés étant majoritairement sur-exprimés. Les ovocytes dépourvus de TZPs sont enclins à arrêter leur développement en métaphase de première division méiotique, bien que présentant un fuseau de division correctement assemblé et des chromosomes bien alignés. Nous proposons que les cellules somatiques modulent la synthèse ou la stabilité d’un sous-ensemble de transcrits ovocytaires par le biais de leurs protrusions cellulaires. Cette modulation améliore la capacité de l’ovocyte à terminer la maturation méiotique, et par extension, les chances de produire un embryonIn female mammals, somatic cells surrounding the oocyte, termed granulosa cells, coordinate the critical stages of post-partum oocyte development, i.e. oocyte growth and meiotic maturation, by dialoguing with the oocyte. This dialogue is primarily mediated by cell-cell contact carried out by granulosa cell protrusions termed transzonal projections (TZPs). TZPs are analogous to filopodia in their snake-like shape, but also in their structural composition. TZPs are located in the zona pellucida, the extracellular matrix surrounding the oocyte, and their extremities establish cellular junctions with the oocyte membrane, i.e. gap and adherens junctions. In my thesis, I investigated the role of TZP-mediated interaction between granulosa cells and the oocyte in oocyte development. By generating a total knockout of Myosin-X, a molecular motor contained in TZPs and participating in filopodia formation, we obtained mouse mutant oocytes with a reduced TZP density at the end of oocyte growth. This reduction does not impede the oocyte from reaching a canonical size. However, it impairs zona pellucida integrity, oocyte-matrix adhesion, and the oocyte transcriptome at the end of oocyte growth, with a subset of transcripts mostly up-deregulated. Importantly, TZP-deprived oocytes tend to cease their development at metaphase of the first meiotic division, despite a well-assembled division spindle and properly aligned chromosomes. We propose that somatic cells modulate the synthesis or stability of a subset of oocyte transcripts through their cellular protrusions. This modulation enhances the oocyte capacity to end meiotic maturation, and by extension, the chances of producing an embryo
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Planelles, Herrero Vicente José. „Bases mécanistiques et structurales de la régulation de l'activité des myosines“. Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066465.
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Les moteurs moléculaires sont des protéines capables de produire une force : elles transforment l'énergie chimique de l'hydrolyse de l'ATP en énergie mécanique. Cette thèse se focalise sur l'étude d'une famille de moteurs moléculaires, les myosines, qui se déplacent le long des filaments d'actine et assurent d'importantes fonctions cellulaires.La myosine VI est une myosine très particulière car elle est la seule à se déplacer vers l'extrémité négative des filaments d'actine. Elle est produite dans la cellule sous forme auto-inhibée, inactive. Dans la cellule, son activité est également régulée par plusieurs protéines interagissant avec la queue C-terminale de la myosine VI. Ces protéines, présentes à des endroits précis de la cellule, recrutent la myosine VI et dictent l'action qu'elle doit effectuer. Des analyses de SAXS, de dispersion de la lumière, de microscopie, d'interaction et de mutagénèse ont permis de mieux comprendre le mécanisme régulant l'adoption de l'état auto-inhibé, ainsi que son activation par le calcium. L'interaction avec différents partenaires a été caractérisée. GIPC1, le partenaire le plus étudié, promeut de façon indirecte la dimérisation et l'activation de la myosine VI.Pendant ma thèse, j'ai également été impliqué dans deux autres projets qui s'inscrivent dans la logique du projet de thèse et qui ont mené à la publication de quatre articles. Deux chapitres, plus brefs, sont donc dédiés à ces projets. Le deuxième chapitre porte sur la régulation de l'activité de la myosine VII par ses partenaires cellulaires. Finalement, le troisième chapitre est dédié à l'étude de la modification allostérique de l'activité des myosines par des petites moléculesMolecular motors are essential agents of force production in the cells: they convert the chemical energy released by the hydrolysis of ATP into mechanical work. This thesis focuses on myosins, a family of molecular motors responsible for actin-based motility. Myosin VI is unique among all of the myosin superfamily members in that it moves in the opposite direction of all other known myosins. Previous work revealed myosin VI tail ability to fold back, constituting a potential auto-inhibited state that prevents motor activity. Several myosin VI partners, binding to the C-terminal tail of the myosin, have been identified and shown to recruit the motor for different functions. In the first chapter of this thesis, the mechanism allowing the regulation of myosin VI activity has been studied using biochemical and biophysical analysis (SAXS, light scattering, microscopy, binding assays and mutagenesis). GIPC1, the most studied myosin VI partners, promotes myosin dimerization and activation. During my PhD, I have been also involved in two other projects, in line with my thesis project, that have led to the publication of four articles. Two shorter chapters are therefore devoted to these projects. The second chapter of my thesis explores myosin VII activity regulation by its cellular partners. Finally, the third chapter is devoted to the allosteric regulation of myosins activity by small molecules
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McMichael, Brooke Kristin Trinrud. „Tropomyosin 4, myosin IIA, and myosin X enhance osteoclast function through regulation of cellular attachment structures“. Columbus, Ohio : Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1206052974.
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4
Planelles, Herrero Vicente José. „Bases mécanistiques et structurales de la régulation de l'activité des myosines“. Electronic Thesis or Diss., Paris 6, 2017. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2017PA066465.pdf.
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Les moteurs moléculaires sont des protéines capables de produire une force : elles transforment l'énergie chimique de l'hydrolyse de l'ATP en énergie mécanique. Cette thèse se focalise sur l'étude d'une famille de moteurs moléculaires, les myosines, qui se déplacent le long des filaments d'actine et assurent d'importantes fonctions cellulaires.La myosine VI est une myosine très particulière car elle est la seule à se déplacer vers l'extrémité négative des filaments d'actine. Elle est produite dans la cellule sous forme auto-inhibée, inactive. Dans la cellule, son activité est également régulée par plusieurs protéines interagissant avec la queue C-terminale de la myosine VI. Ces protéines, présentes à des endroits précis de la cellule, recrutent la myosine VI et dictent l'action qu'elle doit effectuer. Des analyses de SAXS, de dispersion de la lumière, de microscopie, d'interaction et de mutagénèse ont permis de mieux comprendre le mécanisme régulant l'adoption de l'état auto-inhibé, ainsi que son activation par le calcium. L'interaction avec différents partenaires a été caractérisée. GIPC1, le partenaire le plus étudié, promeut de façon indirecte la dimérisation et l'activation de la myosine VI.Pendant ma thèse, j'ai également été impliqué dans deux autres projets qui s'inscrivent dans la logique du projet de thèse et qui ont mené à la publication de quatre articles. Deux chapitres, plus brefs, sont donc dédiés à ces projets. Le deuxième chapitre porte sur la régulation de l'activité de la myosine VII par ses partenaires cellulaires. Finalement, le troisième chapitre est dédié à l'étude de la modification allostérique de l'activité des myosines par des petites moléculesMolecular motors are essential agents of force production in the cells: they convert the chemical energy released by the hydrolysis of ATP into mechanical work. This thesis focuses on myosins, a family of molecular motors responsible for actin-based motility. Myosin VI is unique among all of the myosin superfamily members in that it moves in the opposite direction of all other known myosins. Previous work revealed myosin VI tail ability to fold back, constituting a potential auto-inhibited state that prevents motor activity. Several myosin VI partners, binding to the C-terminal tail of the myosin, have been identified and shown to recruit the motor for different functions. In the first chapter of this thesis, the mechanism allowing the regulation of myosin VI activity has been studied using biochemical and biophysical analysis (SAXS, light scattering, microscopy, binding assays and mutagenesis). GIPC1, the most studied myosin VI partners, promotes myosin dimerization and activation. During my PhD, I have been also involved in two other projects, in line with my thesis project, that have led to the publication of four articles. Two shorter chapters are therefore devoted to these projects. The second chapter of my thesis explores myosin VII activity regulation by its cellular partners. Finally, the third chapter is devoted to the allosteric regulation of myosins activity by small molecules
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Bohil, Aparna Bhaskar Cheney Richard E. „Myosin-X is a molecular motor central to filopodia formation, adhesion, and signaling“. Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2006. http://dc.lib.unc.edu/u?/etd,713.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2006.Title from electronic title page (viewed Oct. 10, 2007). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Cell and Molecular Physiology - School of Medicine." Discipline: Cell and Molecular Physiology; Department/School: Medicine.
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Prestidge, M. C. „Data analysis and processing in X-ray diffraction studies from myosin heads in muscle“. Thesis, Open University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292345.
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Da, Silva Ambrose Gihan. „X-ray diffraction studies of the conformation of myosin heads in relaxed frog muscle“. Thesis, King's College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300318.
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Juanhuix, Gibert Jordi. „Estructura molecular i funció dels músculs vius“. Doctoral thesis, Universitat Autònoma de Barcelona, 2001. http://hdl.handle.net/10803/3330.
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El múscul és un fabulós motor orgànic que a nivell molecular és capaç de convertir energia química, provinent essencialment del menjar, en força mecànica. Al seu estudi s'hi han dedicat grans esforços des de molts camps d'investigació, l'objectiu últim dels quals és trobar la resposta a la pregunta 'd'or': Com fa força i provoca moviment el múscul?Aquesta tesi resol precisament un aspecte essencial de la pregunta: l'orientació dels caps de miosina en diferents estats musculars. Aquests caps són les proteïnes que enllacen els dos elements actius de la contracció: els filaments prims i gruixuts. El punt clau que permet respondre és el fet que el múscul presenta una estructura altament periòdica, on es pot fins i tot definir una cel·la quasicristal·logràfica. Aquesta periodicitat el fa un candidat per ser estudiat amb noves tècniques de difracció basades en la llum de sincrotró.
En conseqüència, i malgrat que tractem amb mostres purament biològiques, aquesta tesi pot ser considerada com un treball clàssic de difracció de mètodes directes, l'esquema brevíssim del qual és com segueix. La mostra és el teixit muscular, que s'obté per dissecció; la tècnica experimental és la difracció de raigs X; de l'anàlisi s'extreuen unes fases i uns mòduls que generen un mapa de densitat electrònica en una dimensió; finalment, el mapa és modelat mitjançant l'orientació de l'estructura cristal·logràfica de les unitats que el componen, de manera que en trobem l'orientació en músculs vius. La metodologia anterior se segueix en dos estats musculars bàsics: en descans (múscul relaxat) i en contracció isomètrica (múscul fent força sense moviment).
La tesi, doncs, està estructurada en 11 capítols que desenvolupen tot el treball que permet arribar a les conclusions finals. Els dos primers capítols estan dedicats a introduir l'estructura i fisiologia del múscul, i la teoria de difracció aplicada a la simetria que presenta, respectivament. El capítol 3 exposa el muntatge experimental i els protocols seguits en cada estat muscular estudiat, mentre que el capítol 4 presenta els resultats experimentals. En el capítol 5 s'extreu la fase del factor d'estructura mitjançant l'ajustament de diverses aproximacions teòriques a les dades en contracció isomètrica. En el capítol 6 es realitza el mateix ajustament en l'estat de descans. El mòdul del factor d'estructura en els dos estats és extret al capítol 7. Amb les dades anteriors, als capítols 8 i 9 s'extreu l'orientació dels caps de miosina en contracció isomètrica i en descans, respectivament. Al capítol 10 s'exposen breument els experiments posteriors realitzats en estats no isomètrics, és a dir, estats en què el múscul experimenta un canvi de longitud, així com el treball que ha de continuar la línia d'investigació d'aquesta tesi. Finalment, al capítol 11 s'extreuen les conclusions del treball en tots els estats musculars estudiats.
Finalment, convé puntualitzar que aquest ha estat realitzat en el marc del consorci del Laboratori de Llum de Sincrotró. Això explica l'especial esment d'aquesta font de raigs X, amb la inclusió de dos annexos que n'exposen les característiques, producció i usos. Així, aquesta tesi no solament pretén tenir rellevància pel contingut original que presenta, sinó que, a més, vol servir d'exemple dels nombrosos usos de la llum de sincrotró, i animar a l'utilització d'aquesta per part dels diferents equips d'investigació d'arreu del país.
The muscle is a fabulous organic machine able to convert, at a molecular level, chemical energy coming mainly from food into mechanical force. Many efforts have been dedicated from many fields of knowledge with the single objective of finding the answer to the golden question: How can muscle produce force and movement?
This thesis answers an essential aspect of the question: how the myosin heads are oriented in different muscular states. These heads are proteins that act as bridges between the two active elements of muscular contraction: the thin and thick filaments. The key point to find the answer this is the periodicity of muscle, high enough to be able to define a quasicrystallograpic structure. This periodicity allows the muscle to be studied by new diffraction techniques using synchrotron light.
As a consequence, even when we are dealing with purely biological samples, this thesis can be regarded as a classic diffraction work using direct methods. The brief summary is as follows. The sample is the muscular tissue, obtained by dissection. The experimental technique is the X ray diffraction; from data analysis we extract phases and moduli from the structure factor of myosin heads. These generate an electronic density map in one dimension, which is further modelled by orientating the crystallographic structure of the myosin heads. This methodology is followed in two basic muscular states: at rest (no contraction performed) and isometric contraction (muscle making force without motion).
Following this schema, the thesis is structured in 11 chapters. The first two introduce the muscle structure and physiology, as well as the diffraction theory of helical structures. Chapter 3 exposes the experimental setup and protocols followed in the different muscular states, whereas chapter 4 presents the experimental results. In chapter 5 we extract the phase of the structure factor by fitting the experimental meridional intensity with several theoretical approximations with the muscle in isometric contraction. Same work is done in chapter 6 with the rest state. The moduli of the structure factor in both states are extracted in chapter 7. Using the obtained data, in chapters 8 and 9 we finally extract the orientation of myosin heads in isometric contraction and rest, respectively. In chapter 10 we briefly expose the following experiments, done in non-isometric states, when muscle changes the length, as well as the future work to be done after this thesis. Finally, in chapter 11 we list the conclusions for every studied muscular state.
As a final point, we should remark that this work has been done in the Laboratori de Llum de Sincrotró. This explains why 2 more appendixes have been included exposing the characteristics, production and use of synchrotron sources. In fact, this thesis not only pretends to extend the knowledge of muscle, but also to be an example of the many uses of synchrotron light. We hope to contribute to expand the knowledge and use of this powerful tool among the national research groups.
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岩野, さやか. „細胞の分裂軸を制御するPCTK1-KAP0-myosin Xシグナル伝達経路の解明“. Kyoto University, 2015. http://hdl.handle.net/2433/199560.
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Addisu, Anteneh. „Natriuretic peptides as a humoral link between the heart and the gastrointestinal system“. [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002406.
Der volle Inhalt der QuelleBuchteile zum Thema "Myosine-X"
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Tokuo, Hiroshi. „Myosin X“. In Advances in Experimental Medicine and Biology, 391–403. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38062-5_17.
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Tokuo, Hiroshi. „Myosin X“. In Encyclopedia of Signaling Molecules, 3314–18. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-67199-4_404.
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Gewies, Andreas, Jürgen Ruland, Alexey Kotlyarov, Matthias Gaestel, Shiri Procaccia, Rony Seger, Shin Yasuda et al. „Myosin X“. In Encyclopedia of Signaling Molecules, 1173–77. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-0461-4_404.
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Cecchi, Giovanni, M. Angela Bagni, Barbara Colombini, Christopher C. Ashley, Heinz Amenitsch, Sigrid Bernstorff und Peter J. Griffiths. „Use of Sinusoidal Length Oscillations to Detect Myosin Conformation by Time- Resolved X-Ray Diffraction“. In Advances in Experimental Medicine and Biology, 267–77. Boston, MA: Springer US, 2003. http://dx.doi.org/10.1007/978-1-4419-9029-7_25.
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Arata, T., S. Kimura, Y. Sugimoto, Y. Takezawa, N. Iwasaki und K. Wakabayashi. „Structure of the Monomeric Actin-Myosin Head Complex as Revealed by X-Ray Solution Scattering“. In Advances in Experimental Medicine and Biology, 73–78. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4684-6039-1_9.
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Reconditi, Massimo, Ian Dobbie, Malcolm Irving, Olivier Diat, Peter Boesecke, Marco Linari, Gabriella Piazzesi und Vincenzo Lombardi. „Myosin Head Movements during Isometric Contraction Studied by X-Ray Diffraction of Single Frog Muscle Fibres“. In Advances in Experimental Medicine and Biology, 265–70. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4684-6039-1_31.
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Oshima, Kanji, Yasunori Takezawa, Yasunobu Sugimoto, Maya Kiyotoshi und Katsuzo Wakabayashi. „Modeling Analysis of Myosin-Based Meridional X-Ray Reflections from Frog Skeletal Muscles in Relaxed and Contracting States“. In Advances in Experimental Medicine and Biology, 243–49. Boston, MA: Springer US, 2003. http://dx.doi.org/10.1007/978-1-4419-9029-7_23.
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Takezawa, Yasunori, Yasunobu Sugimoto und Katsuzo Wakabayashi. „Extensibility of the Actin and Myosin Filaments in Various States of Skeletal Muscle as Studied by X-Ray Diffraction“. In Advances in Experimental Medicine and Biology, 309–17. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4684-6039-1_36.
Der volle Inhalt der QuelleKonferenzberichte zum Thema "Myosine-X"
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Fujimura, K., T. Fujimoto, M. Takemoto, K. Oda, S. Maehama und A. Kuramoto. „INTERACTION OF MEMBRANE GLYCOPROTEIN GPIIb AND Ilia WITH CYTOSKELETAL PROTEINS DURING PLATELET ACTIVATION“. In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643515.
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Experiments were designed and performed to analyse the cytoskeleton assembly and the interaction of glycoprotein (GP)IIb, IIIa and cytoskeletal proteins during platelet activation. A23187 stimulated 125I labeled platelets were solubilised with Triton X-100 solution and centrifuged. The insoluble fraction were analysed by two dimensional electrophoresis and the soluble fraction were fractionated with 5-25% sucrose gradient centrifugation and analysed by SDS PAGE. In Triton X-100 insoluble fraction, high molecular weight protein fraction(MW > 106) was present after stimulation which were consisted of actin binding protein(ABP), myosin heavy chain(MHC), actin and GPIIb and IIIa. And some of the ABP and MHC formed dimer. ABP and actin in this fraction were decreased with 1 mM CaCl2 treatment but the reduction of ABP was inhibited by leupeptm. In Triton X-100 soluble fraction after stimulation, some of the ABP, MHC, P235 protein, actin and small amount of GPIIb, IIIa were sedimented in the same high density fraction but most proteins were sedimented as a monomer form or GPIIb-IIIa complex form. The GPIIb, IIIa incorporation in high molecular weight protein fraction or high density fraction was absent in Ca++ chelating condition or the presence of competitive fibrinogen binding inhibitor which blocked the platelet aggregation. It is concluded that cytoskeletal proteins and GPIIb, IIIa are assembled each other and formed high molecular weight protein fraction or dimer formation during activation. In stimulated platelets these assembled cytoskeletal proteins containing GPIIb, IIIa were also found in Triton X-100 soluble fraction as a precursor of high molecular weight fraction in Triton X-100 insoluble fraction. The binding of fibrinogen to GPIIb-IIIa complex induce the linkage of GPIIb, IIIa to assembled cytoskeletal proteins.
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Shibatay, N., K. Tanaka, K. Okamoto und T. Onji. „REORGANIZATION OF ACTIN AND MYOSIN IN THE ACTIVATED PLATELETS“. In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1643539.
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This study was done to clarify the intracellular dynamic arrangements of myosin(My) and actin(Ac) in activation process of human platelets (PLs) from unactivated to activated stage (clot retraction) in electron microscopy. The observation of unactivated PLs was done either in the fresh whole blood fixed directly with 0.1 % glutaraldehyde or in PLs isolated by gel filtration of platelet rich plasma(PRP) containing prostaglandin I2 (10 ng/ml). The isolated PLs mounted on a glass cover slip were used as activated PLs (adrerent ones). The contracted PLs were prepared in PRP incubated with thrombin (0.5 u/ml) and 20 mM CaCl- for 10-60 min. Treating PLs with 0.15 % Triton X-100 containing 0.05 % glutaraldehyde produced cytoskeleton. My and F-Ac were identified by an indirect immuno-cytochemical method using the specific antibody (rabbit IgG) against PL-My and protein A-gold and by demonstration of in “arrow-head” decoration by Ishikawa's method using skeletal meromyosin (HMM), respectively. [Results] (1) Unactivated PLs. Mys in monomer or oligomer distributed homogenously in scare association with cytoskeleton. Cytoskeletons were exclusively composed of F-Ac networks of crossolinked short filaments which were thinly distributed in the cytoplasm with partial connection to the cell membrance. (2) Surface activated spreading PLs. PLs adhered to the glass cover slip in dendritic forms. Mys were densely located around granulomere and formed linear arrays associated with F-Ac filaments of the cytoskeleton surrounding the granulomere and running straightly in cytoplasm. (3) Contracted PLs. Activated PLs protruded several filopodia in which networks or bundles of F-Ac filaments were found connecting to extracellular fibrin strand through cell membrene. Microfilaments formed arrow-head decoration with HMM pointing toward the cell body. The cytoskeleton in contracted PLs contained thick filaments of My-polymers attaching to F-Ac filaments end by end. It is concluded that the reorganization of Ac-My is the basis for the shape change, secretion and clot retraction of activated PLs.