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Auswahl der wissenschaftlichen Literatur zum Thema „Myosin A“
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Zeitschriftenartikel zum Thema "Myosin A"
1
Siththanandan, Verl B., und James R. Sellers. „Regulation of myosin 5a and myosin 7a“. Biochemical Society Transactions 39, Nr. 5 (21.09.2011): 1136–41. http://dx.doi.org/10.1042/bst0391136.
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The myosin superfamily is diverse in its structure, kinetic mechanisms and cellular function. The enzymatic activities of most myosins are regulated by some means such as Ca2+ ion binding, phosphorylation or binding of other proteins. In the present review, we discuss the structural basis for the regulation of mammalian myosin 5a and Drosophila myosin 7a. We show that, although both myosins have a folded inactive state in which domains in the myosin tail interact with the motor domain, the details of the regulation of these two myosins differ greatly.
2
Baines, I. C., H. Brzeska und E. D. Korn. „Differential localization of Acanthamoeba myosin I isoforms.“ Journal of Cell Biology 119, Nr. 5 (01.12.1992): 1193–203. http://dx.doi.org/10.1083/jcb.119.5.1193.
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Acanthamoeba myosins IA and IB were localized by immunofluorescence and immunoelectron microscopy in vegetative and phagocytosing cells and the total cell contents of myosins IA, IB, and IC were quantified by immunoprecipitation. The quantitative distributions of the three myosin I isoforms were then calculated from these data and the previously determined localization of myosin IC. Myosin IA occurs almost exclusively in the cytoplasm, where it accounts for approximately 50% of the total myosin I, in the cortex beneath phagocytic cups and in association with small cytoplasmic vesicles. Myosin IB is the predominant isoform associated with the plasma membrane, large vacuole membranes and phagocytic membranes and accounts for almost half of the total myosin I in the cytoplasm. Myosin IC accounts for a significant fraction of the total myosin I associated with the plasma membrane and large vacuole membranes and is the only myosin I isoform associated with the contractile vacuole membrane. These data suggest that myosin IA may function in cytoplasmic vesicle transport and myosin I-mediated cortical contraction, myosin IB in pseudopod extension and phagocytosis, and myosin IC in contractile vacuole function. In addition, endogenous and exogenously added myosins IA and IB appeared to be associated with the cytoplasmic surface of different subpopulations of purified plasma membranes implying that the different myosin I isoforms are targeted to specific membrane domains through a mechanism that involves more than the affinity of the myosins for anionic phospholipids.
3
Berg, Jonathan S., Bradford C. Powell und Richard E. Cheney. „A Millennial Myosin Census“. Molecular Biology of the Cell 12, Nr. 4 (April 2001): 780–94. http://dx.doi.org/10.1091/mbc.12.4.780.
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The past decade has seen a remarkable explosion in our knowledge of the size and diversity of the myosin superfamily. Since these actin-based motors are candidates to provide the molecular basis for many cellular movements, it is essential that motility researchers be aware of the complete set of myosins in a given organism. The availability of cDNA and/or draft genomic sequences from humans,Drosophila melanogaster, Caenorhabditis elegans, Arabidopsis thaliana,Saccharomyces cerevisiae, Schizosaccharomyces pombe, andDictyostelium discoideum has allowed us to tentatively define and compare the sets of myosin genes in these organisms. This analysis has also led to the identification of several putative myosin genes that may be of general interest. In humans, for example, we find a total of 40 known or predicted myosin genes including two new myosins-I, three new class II (conventional) myosins, a second member of the class III/ninaC myosins, a gene similar to the class XV deafness myosin, and a novel myosin sharing at most 33% identity with other members of the superfamily. These myosins are in addition to the recently discovered class XVI myosin with N-terminal ankyrin repeats and two human genes with similarity to the class XVIII PDZ-myosin from mouse. We briefly describe these newly recognized myosins and extend our previous phylogenetic analysis of the myosin superfamily to include a comparison of the complete or nearly complete inventories of myosin genes from several experimentally important organisms.
4
Hammer, J. A., B. Bowers, B. M. Paterson und E. D. Korn. „Complete nucleotide sequence and deduced polypeptide sequence of a nonmuscle myosin heavy chain gene from Acanthamoeba: evidence of a hinge in the rodlike tail.“ Journal of Cell Biology 105, Nr. 2 (01.08.1987): 913–25. http://dx.doi.org/10.1083/jcb.105.2.913.
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We have completely sequenced a gene encoding the heavy chain of myosin II, a nonmuscle myosin from the soil ameba Acanthamoeba castellanii. The gene spans 6 kb, is split by three small introns, and encodes a 1,509-residue heavy chain polypeptide. The positions of the three introns are largely conserved relative to characterized vertebrate and invertebrate muscle myosin genes. The deduced myosin II globular head amino acid sequence shows a high degree of similarity with the globular head sequences of the rat embryonic skeletal muscle and nematode unc 54 muscle myosins. By contrast, there is no unique way to align the deduced myosin II rod amino acid sequence with the rod sequence of these muscle myosins. Nevertheless, the periodicities of hydrophobic and charged residues in the myosin II rod sequence, which dictate the coiled-coil structure of the rod and its associations within the myosin filament, are very similar to those of the muscle myosins. We conclude that this ameba nonmuscle myosin shares with the muscle myosins of vertebrates and invertebrates an ancestral heavy chain gene. The low level of direct sequence similarity between the rod sequences of myosin II and muscle myosins probably reflects a general tolerance for residue changes in the rod domain (as long as the periodicities of hydrophobic and charged residues are largely maintained), the relative evolutionary "ages" of these myosins, and specific differences between the filament properties of myosin II and muscle myosins. Finally, sequence analysis and electron microscopy reveal the presence within the myosin II rodlike tail of a well-defined hinge region where sharp bending can occur. We speculate that this hinge may play a key role in mediating the effect of heavy chain phosphorylation on enzymatic activity.
5
Heintzelman, M. B., T. Hasson und M. S. Mooseker. „Multiple unconventional myosin domains of the intestinal brush border cytoskeleton“. Journal of Cell Science 107, Nr. 12 (01.12.1994): 3535–43. http://dx.doi.org/10.1242/jcs.107.12.3535.
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Representatives of class V and class VI unconventional myosins are identified as components of the intestinal brush border cytoskeleton. With brush border myosin-I and myosin-II, this brings to four the number of myosin classes associated with this one subcellular domain and represents the first characterization of four classes of myosins expressed in a single metazoan cell type. The distribution and cytoskeletal association of each myosin is distinct as assessed by both biochemical fractionation and immunofluorescence localization. Myosin-VI exists in both the microvillus and terminal web although the terminal web is the predominant site of concentration. Myosin-V is present in the terminal web and, most notably, at the distal ends of the microvilli, thus becoming the first actin-binding protein to be localized to this domain as assessed by both immunohistochemical and biochemical methods. In the undifferentiated enterocytes of the intestinal crypts, myosin-VI is expressed but not yet localized to the brush border, in contrast to myosin-V, which does demonstrate an apical distribution in these cells. An assessment of myosin abundance indicates that while myosin-II is the most abundant in the cell and in the brush border, brush border myosin-I is only slightly less abundant in contrast to myosins-V and -VI, both of which are two orders of magnitude less abundant than the others. Extraction studies indicate that of these four myosins, myosin-V is the most tightly associated with the brush border membrane, as detergent, in addition to ATP, is required for efficient solubilization.
6
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.
7
Post, P. L., G. M. Bokoch und M. S. Mooseker. „Human myosin-IXb is a mechanochemically active motor and a GAP for rho“. Journal of Cell Science 111, Nr. 7 (01.04.1998): 941–50. http://dx.doi.org/10.1242/jcs.111.7.941.
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The heavy chains of the class IX myosins, rat myr5 and human myosin-IXb, contain within their tail domains a region with sequence homology to GTPase activating proteins for the rho family of G proteins. Because low levels of myosin-IXb expression preclude purification by conventional means, we have employed an immunoadsorption strategy to purify myosin-IXb, enabling us to characterize the mechanochemical and rho-GTPase activation properties of the native protein. In this report we have examined the light chain content, actin binding properties, in vitro motility and rho-GTPase activity of human myosin-IXb purified from leukocytes. The results presented here indicate that myosin-IXb contains calmodulin as a light chain and that it binds to actin with high affinity in both the absence and presence of ATP. Myosin-IXb is an active motor which, like other calmodulin-containing myosins, exhibits maximal velocity of actin filaments (15 nm/second) in the absence of Ca2+. Native myosin-IXb exhibits GAP activity on rho. Class IX myosins may be an important link between rho and rho-dependent remodeling of the actin cytoskeleton.
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Wylie, Steven R., und Peter D. Chantler. „Myosin IIC: A Third Molecular Motor Driving Neuronal Dynamics“. Molecular Biology of the Cell 19, Nr. 9 (September 2008): 3956–68. http://dx.doi.org/10.1091/mbc.e07-08-0744.
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Neuronal dynamics result from the integration of forces developed by molecular motors, especially conventional myosins. Myosin IIC is a recently discovered nonsarcomeric conventional myosin motor, the function of which is poorly understood, particularly in relation to the separate but coupled activities of its close homologues, myosins IIA and IIB, which participate in neuronal adhesion, outgrowth and retraction. To determine myosin IIC function, we have applied a comparative functional knockdown approach by using isoform-specific antisense oligodeoxyribonucleotides to deplete expression within neuronally derived cells. Myosin IIC was found to be critical for driving neuronal process outgrowth, a function that it shares with myosin IIB. Additionally, myosin IIC modulates neuronal cell adhesion, a function that it shares with myosin IIA but not myosin IIB. Consistent with this role, myosin IIC knockdown caused a concomitant decrease in paxillin-phospho-Tyr118 immunofluorescence, similar to knockdown of myosin IIA but not myosin IIB. Myosin IIC depletion also created a distinctive phenotype with increased cell body diameter, increased vacuolization, and impaired responsiveness to triggered neurite collapse by lysophosphatidic acid. This novel combination of properties suggests that myosin IIC must participate in distinctive cellular roles and reinforces our view that closely related motor isoforms drive diverse functions within neuronal cells.
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O'Halloran, T. J., S. Ravid und J. A. Spudich. „Expression of Dictyostelium myosin tail segments in Escherichia coli: domains required for assembly and phosphorylation.“ Journal of Cell Biology 110, Nr. 1 (01.01.1990): 63–70. http://dx.doi.org/10.1083/jcb.110.1.63.
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The assembly of myosins into filaments is a property common to all conventional myosins. The ability of myosins to form filaments is conferred by the tail of the large asymmetric molecule. We are studying cloned portions of the Dictyostelium myosin gene expressed in Escherichia coli to investigate functional properties of defined segments of the myosin tail. We have focused on five segments derived from the 68-kD carboxyl-terminus of the myosin tail. These have been expressed and purified to homogeneity from E. coli, and thus the boundaries of each segment within the myosin gene and protein sequence are known. We identified an internal 34-kD segment of the tail, N-LMM-34, which is required and sufficient for assembly. This 287-amino acid domain represents the smallest tail segment purified from any myosin that is capable of forming highly ordered paracrystals characteristic of myosin. Because the assembly of Dictyostelium myosin can be regulated by phosphorylation of the heavy chain, we have studied the in vitro phosphorylation of the expressed tail segments. We have determined which segments are phosphorylated to a high level by a Dictyostelium myosin heavy chain kinase purified from developed cells. While LMM-68, the 68-kD carboxyl terminus of Dictyostelium myosin, or LMM-58, which lacks the 10-kD carboxyl terminus of LMM-68, are phosphorylated to the same extent as purified myosin, subdomains of these segments do not serve as efficient substrates for the kinase. Thus LMM-58 is one minimal substrate for efficient phosphorylation by the myosin heavy chain kinase purified from developed cells. Taken together these results identify two functional domains in Dictyostelium myosin: a 34-kD assembly domain bounded by amino acids 1533-1819 within the myosin sequence and a larger 58-kD phosphorylation domain bounded by amino acids 1533-2034 within the myosin sequence.
10
Hasson, T., und M. S. Mooseker. „Porcine myosin-VI: characterization of a new mammalian unconventional myosin.“ Journal of Cell Biology 127, Nr. 2 (15.10.1994): 425–40. http://dx.doi.org/10.1083/jcb.127.2.425.
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We have cloned a new mammalian unconventional myosin, porcine myosin-VI from the proximal tubule cell line, LLC-PK1 (CL4). Porcine myosin-VI is highly homologous to Drosophila 95F myosin heavy chain, and together these two myosins comprise a sixth class of myosin motors. Myosin-VI exhibits ATP-sensitive actin-binding activities characteristic of myosins, and it is associated with a calmodulin light chain. Within LLC-PK1 cells, myosin-VI is soluble and does not associate with the major actin-containing domains. Within the kidney, however, myosin-VI is associated with sedimentable structures and specifically locates to the actin- and membrane-rich apical brush border domain of the proximal tubule cells. This motor was not enriched within the glomerulus, capillaries, or distal tubules. Myosin-VI associates with the proximal tubule cytoskeleton in an ATP-sensitive fashion, suggesting that this motor is associated with the actin cytoskeleton within the proximal tubule cells. Given the difference in association of myosin-VI with the apical cytoskeleton between LLC-PK1 cells and adult kidney, it is likely that this cell line does not fully differentiate to form functional proximal tubule cells. Myosin-VI may require the presence of additional elements, only found in vivo in proximal tubule cells, to properly locate to the apical domain.
Dissertationen zum Thema "Myosin A"
1
Zhu, Jing. „The role of nonmuscle myosin IIA in endothelial cell“. Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/11006.
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Thesis (M.S.)--West Virginia University, 2010.Title from document title page. Document formatted into pages; contains viii, 37 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 33-37).
2
Stevens, Richard. „Two light chains of the unconventional myosin Myo2p /“. Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/9226.
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3
Guimard, Laurent. „Modélisation et synthèse de peptides interagissant avec une protéine cible : application au complexe calmoduline-RS20“. Montpellier 1, 1995. http://www.theses.fr/1995MON1T037.
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4
Petzoldt, Astrid G. „DE-cadherin regulates unconventional myosin ID through myosin IC in Drosophila melanogaster“. Nice, 2009. http://www.theses.fr/2009NICE4048.
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L’établissement précis de l’asymétrie G/D stéréotypée, qui est contrôlé par un programme génétique, est crucial pour le fonctionnement d’un organisme. Ce n’est que depuis récemment que le mécanisme de l’établissement de l’asymétrie G/D est étudié chez l’invertébré Drosophila Melanogaster (Hozumi et al. , 2006 ; Speder et al. , 2006). La Myosine non conventionnelle de type ID (MyoID) a été caractérisée comme un déterminant de la rotation dextrale de la plaque génitale mâme pendant le stade pupal. Afin d’identifier de nouveaux effecteurs de MyoID, nous nous sommes concentrés sur son plus proche homologue, MyoIC, car sa surexpression mime le phénotype perte de fonction de MyoID, ce qui entraîne une inversion de l’axe G/D et une rotation sinistrale des organes génitaux. Nous présentons des évidences que ce situs inversu phénotype es entraîné par l’inhibition de la fonction de MyoID par MyoIC, conséquemment nous définirons MyoIC comme un facteur anti-dextral. Il a été montré que la queue de MyoID pourrait interagir physiquement avec la beta-Catenine, (Speder et al. , 2006). Nos expériences de perte et gain de fonction de la DE-Cadhérine, un composant majeur des jonctions adhérentes, avons révélées une interaction linéaire entre DE-Cadherine et les deux Myosines. DE-Cadhérine est capable de contrôler l’expression de MyoIC en agissant comme inhibiteur de MyoIC. Car la fonctionnalité de MyoID est de réguler par l’expression de MyoIC. MyoIC fonctionne comme médiateur entre DE-Cadhérine et MyoID. Nous proposons un nouveau réseau de régulation pour l’établissement de l’asymétrie G/D dans lequel la DE-Cadhérine affecte l’activité de MyoID à travers la régulation de l’expression de LyoICThe accurate establishment of stereotyped L/R asymetry is subject to a strict genetic program and crucial for the functionality of the organism. It is only recently that the mechanism of L/R asymmetry establishment is exploited in the invertebrate species Drosphophila melanogaster (Hozumi et al. , 2006 ; Speder et al. , 2006). The unconventional type ID myosin (MyoID) has been characterised as a dextral determinant accountable for the clockwise (dextral) rotation of the male genital plate during pupae stage. In our attempt to isolate new components of the L/R mechanism, we first focussed on MyoIC, the closest homologue of genitalia, thus L/R axis inversion. We provide evidence that this situs inversus phenotype is du to an inhibition of MyoID function through MyoIC and consequently define MyoIC as an anti-dextral effector of MyoID. An interaction between MyoID and adherents junctions had been suggested by Speder et al. (2006) as the authors could show by two-hybrid screen and GST pull down that MyoID tail and beta-catenin cal physically interact. Our DE-cadherin loss and gain of function studies revealed a linear interaction between DE-cadherin zand the unconventional myosins MyoID and MyoIC. DE-cadherin controls MyoIC expression, acting as inhibitor of MyoIC. As MyoID functionality is regulated by MyoIC expression, myoIC functions as a mediator between DE-cadherin and myoID. In summary, we present in this study a new regulatory network of L/R asymmetry establishment, where DE-cadherin affects MyoID activity through regulation of MyoIC protein expression
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Ripoll, Léa. „Role of myosin VI and actin dynamics in membrane remodeling during pigmentation“. Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCB102.
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Le trafic intracellulaire consiste en la formation et le transport de vésicules ou tubules qui acheminent des composants protéiques et lipidiques entre les différents organites ou avec la membrane plasmique. L’élaboration de ces tubulo-vésicules est initiée par le remodelage local d’une membrane, tout d’abord en générant une courbure puis un bourgeon qui, s’allongeant, forme la tubulo-vésicule. Enfin, la rupture de la membrane, ou scission, libère le transporteur nouvellement formé. Ces étapes repose sur un sculptage profond de la membrane. Ceci requière des forces générées par des moteurs moléculaires, lesquels s’associent aux cytosquelettes comme les microtubules ou les filaments d’actine. Afin de mieux comprendre comment le cytosquelette et leurs moteurs façonnent ces transporteurs, nous avons examiné le rôle de l’actine et de la myosine VI dans la formation de tubules membranaires aux mélanosomes. Les mélanosomes sont des organites apparentés aux lysosomes, générés dans les mélanocytes de la peau et de la choroïde de l’œil, et qui sont le lieu de synthèse et de stockage d’un pigment, la mélanine. Dans l’épiderme, ces compartiments spécialisés évoluent par différentes étapes de maturation qui aboutissent à leurs transferts aux cellules voisines, les kératinocytes. Les mélanosomes sont des organites dynamiques qui reçoivent et recyclent constamment des composants membranaires, comme la SNARE VAMP7. Nous résultats montrent que la myosine VI et son adapteur optineurine se localisent à un sous-domaine spécifique de la membrane des mélanosomes, ou elles contrôlent la scission de tubules. En effet, l’activité motrice de la myosine VI et le réseau d’actine branchée, dépendant des complexes Arp2/3 et WASH, permettent la constriction des membranes du tubule et son détachement du mélanosome. Un défaut de scission de ces tubes engendre des mélanosomes plus pigmentés, enrichis en cargos et au pH plus acide. L’altération de l’homéostasie du mélanosome affecte sa fonction, comme sa capacité à être sécrété et transféré aux kératinocytes. Nos résultats démontrent que la myosine VI en coopération avec le cytosquelette d’actine permet la constriction et fission de membranes aux mélanosomes. Les intermédiaires de transport ainsi formés recyclent des protéines cargos pour leur possible réutilisation, et participent ainsi au maintien de l’homéostasie et de la fonction de ces organitesIntracellular transport among organelles and the plasma membrane occurs through the formation and transport of vesicular and tubular membrane carriers. The formation of these carriers requires first the bending of membrane and the generation of a bud, followed by its elongation to form the tubule-vesicle. Lastly, the carrier is released from the membrane source by the scission of the membrane. Importantly, all these different steps need an accurate orchestration to properly deform the membrane. The actions exerted by molecular motors onto microtubule and actin cytoskeletons provide forces onto membrane that contribute to its remodeling during the biogenesis of carrier. Actin filaments (F-actin) and myosins are thought to participate in the initiation and the fission of carriers. However, the role of actin machinery during carrier biogenesis remains elusive. We thus decided to address the role of F-actin and the actin-based motor myosin VI in the formation of tubular intermediates at melanosome. Melanosomes are lysosome-related organelles of skin melanocytes and eye pigment cells that function in the synthesis and storage of the melanin pigment. Melanosomes originate from endosomes and progressively mature into fully pigmented compartments, which fate is to be secreted and transferred to neighboring keratinocytes. Melanosomes are dynamic organelles that constantly receive, but also recycle proteins such as the SNARE VAMP7 through the formation and release of tubular intermediates. Our work reveals that myosin VI, together with Arp2/3- and WASH-mediated branched actin localize at specific melanosomal subdomains where they promote the constriction and scission of tubular intermediates. This fission event allows the export of components such as VAMP7 from melanosomes and promotes their maturation and subsequent transfer to keratinocytes. Altogether, our results uncover a new role for myosin VI and F-actin in the constriction and scission of membrane tubules at melanosome that is required for organelle homeostasis and function
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Saeki, Nobutaka. „The Function of Myosin IX: the Ninth Class of Myosin Superfamily: a Dissertation“. eScholarship@UMMS, 2005. http://escholarship.umassmed.edu/gsbs_diss/294.
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Among 18 family members in the myosin superfamily, myosin IX is unique by possessing a GTPase activating protein (GAP) for Rho. It is also attention-grabbing since it is a single-headed processive motor, as well as a minus-end directed motor. Although many biochemical properties have been revealed, its physiological function is largely unknown. As an initial step to address this question, I attempted to find the binding partner of myosin IXb using the yeast two-hybrid screen. Through the screen using the tail domain of myosin IXb as bait I found BIG1, a guanine nucleotide exchange factor (GEF) for ADP-ribosylation factor (Arfl), as a potential binding partner for myosin IXb. The interaction between myosin IXb and BIG1 was demonstrated by co-immunoprecipitation of endogenous myosin IXb and BIG1 with anti-BIG1 antibodies in normal rat kidney (NRK) cells. Using the isolated proteins, it was demonstrated that myosin IXb and BIG1 directly bind to each other. Various truncation mutants of the myosin IXb tail domain were produced and it was revealed that the binding region of myosin IXb to BIG1 is the zinc finger/GAP domain. Interestingly, the GAP activity of myosin IXb was significantly inhibited by addition of BIG1 with IC50 of 0.06 μM. The RhoA binding to myosin IXb was inhibited by the addition of BIG1 with a concentration similar to that which inhibit the GAP activity. Likewise, RhoA inhibited the BIG1 binding of myosin IXb. These results suggest that BIG1 and RhoA compete with each other for the binding to myosin IXb, thus resulting in the inhibition of the GAP activity by BIG1. The present study identified BIG1, the ArfGEF, as a new binding partner for myosin IXb, which inhibited the GAP activity of myosin IXb.
Together, the results imply that the RhoGAP activity of myosin IXb is down-regulated by BIG1 at the Golgi, where myosin IXb could be involved in the regulation of actin cytoskeleton through the Rho-signaling pathway.
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Cartón, García Fernando. „Myosin VB in intestinal pathogenesis“. Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/458251.
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Miosina VB es una proteína que actúa como un motor molecular usando la energía del ATP para moverse a lo largo de filamentos de actina. Participa en el trafico intracelular de endosomas de reciclaje en la parte subapical de células polarizadas y no polarizadas. Su expresión es muy abundante en el intestino donde participa en el establecimiento y mantenimiento de la polaridad de los enterocitos. Mutaciones en MYO5B causan la enfermedad de inclusión de microvellosidades, in raro trastorno congénito que afecta a las células epiteliales del intestino cursando con diarrea acuosa persistente que suele ser fatal. Esta enfermedad se caracteriza por la presencia de alteraciones morfológicas en los enterocitos, atrofia de las vellosidades y deslocalización de proteínas del polo apical y basolateral del enterocito. Su patología molecular no se conoce, principalmente por la falta de modelos animales. En el presente estudio, describimos un versátil modelo murino con inactivación constitutiva de Myo5b e inactivación condicional en las células epiteliales intestinales inducida por tamoxifeno. En ambos casos, los animales muestras un cuadro clínico muy semejantes al de los pacientes con enfermedad de inclusión de microvellosidades, presentado diarrea y deshidratación que causan la muerte del animal. A nivel histológico, el intestino muestra las mismas alteraciones en los enterocitos que las presentes en pacientes humanos, incluyendo atrofia de vellosidades y deslocalización de marcadores proteicos. Además, la inactivación de Myo5b también provocó hiperproliferación de las criptas intestinales. Por lo tanto, el modelo animal presentado constituye una herramienta muy útil para investigar las causas moleculares de la enfermedad y ensayar de manera preclínica fármacos u otras opciones terapéuticas. Por otro lado, la pérdida de polaridad y diferenciación es también una de las señas de identidad de los carcinomas metastásicos avanzados y correlaciona con un mal pronóstico de los pacientes. En concreto, para el cáncer colorrectal, investigaciones previas llevadas a cabo en nuestro laboratorio ya han demostrado que la pérdida de miosina IA promueve la progresión la enfermedad y tiene actividad supresora de tumores. Dicha proteína es abundante en el borde en cepillo de los enterocitos, y participa en el mantenimiento de la estructura polarizada. Otros estudios han señalado la relación entre la inactivación de MYO5B con un incremento en la motilidad e invasión de células de cáncer gástrico, aunque todavía no se conoce nada de su relación con en el cáncer colorrectal. Para resolver esta cuestión, hemos diseñado modelos in vitro inducibles por doxiciclina para sobre expresar y reducir la expresión de dicha proteína en líneas celulares de cáncer de colon. Además, se ha empleado la tecnología CRISPR/Cas9 para inactivar la expresión de MYO5B en la línea de cáncer de colon Caco2-BBE. Los resultados muestran cambios en la polarización y diferenciación de dichas líneas celulares, de acuerdo con observaciones previas. También se ha observado una posible relación entre MYO5B y la capacidad de movilidad e invasión de las líneas de cáncer de colon. Sin embargo, la hiperproliferación observada en el intestino de los ratones no se reproduce en las líneas de cáncer de colon empleadas tras reducir o sobre expresar MYO5B, o en modelos xenograft subcutáneos in vivo de dichas líneas. Por otro lado, usando un microarray de tejidos con 155 muestras de tumores primarios de pacientes con cáncer colorrectal en estadio Dukes C se ha comprobado que una reducción en la expresión de MYO5B se asocia con una disminución en el tiempo de recaída y en la supervivencia total de los pacientes de cáncer de colon. Además, tumores con un grado de diferenciación bajo también expresan niveles de MYO5B significativamente reducidos. Finalmente, todos estos resultados indican que MYO5B juega un papel importante en la diferenciación del intestino normal y de las líneas de cáncer de colon. De la misma manera, MYO5B también podría desempeñar un papel en la progresión del cáncer colorrectal promoviendo movilidad e invasión de las células tumorales.Myosin VB is a molecular motor protein that uses the energy of ATP to move along actin filaments. It participates in the recycling endosomes trafficking in the subapical cytoplasmic region of non-polarized and polarized cells. It is highly expressed in the small and large intestine, where its role in the establishment of polarized function in enterocytes is also well known. Inactivating mutations of MYO5B have been associated with microvillus inclusion disease (MVID), a rare congenital disorder of the intestinal epithelial cells that presents with persistent life-threatening watery diarrhea. It is characterized by morphological enterocyte abnormalities such as microvillus atrophy and mislocalization of apical and basolateral protein transporters. The molecular pathology of the disease is not well known mainly due to the lack of animal models. In the present study, we report a versatile murine model with targeted inactivation of Myo5b. This model allowed us to generate and characterized a constitutive Myo5b knockout mice and a tamoxifen-inducible intestinal-epithelium-specific Myo5b knockout. In both cases, the mice closely resemble the phenotype of MVID patients, developing watery diarrhea and dehydration causing the death of the animal. Histological study of the intestine showed all the characteristic enterocyte defects observed in MVID patients, including microvillus atrophy and mislocalization of protein markers. Moreover, the inactivation of MYO5B also originated hyperproliferation of the intestinal crypts. Therefore, our mice constitute a useful model to further investigate the underlying molecular mechanism of this disease and to preclinically assess the efficacy of novel therapeutic approaches. In addition, hyperproliferation as well as loss of cell polarity, differentiation, and tissue architecture are hallmarks of advanced metastatic carcinomas and strongly correlate with poor patient prognosis. Specifically, for colorectal cancer, the third most common type of cancer worldwide, we have previously demonstrated that the loss of brush border MYO1A, also involved in cell polarity, promotes cancer progression and has tumor suppressor activity. Other studies have indicated a relationship between MYO5B inactivation and gastric cancer, promoting invasion and motility, but little is known regarding its role in colorectal cancer. To address this question, we have developed novel doxycycline-inducible in vitro models of MYO5B overexpression and downregulation. Moreover, we have generated MYO5B knockout Caco2-BBE cells using CRISPR/Cas9 technology. Our results showed changes in the polarization and differentiation of colon cancer cells, in agreement with previous observations in the normal intestine. Moreover, we have observed a relationship between MYO5B and the motility and invasion capacity of colon cancer cells, indicating a possible role of MYO5B in colon cancer progression. However, the effect of MYO5B loss in cell proliferation observed in our Myo5b knockout mice could not be confirmed in our models in vitro and in vivo, employing cell line-derived xenografts. In addition, using a tissue microarray containing triplicate samples from 155 primary Dukes C colorectal tumors, reduced MYO5B expression was found to be associated with shorter disease-free and overall survival of the patients. Moreover, poorly differentiated tumors showed significantly reduced expression of MYO5B. Collectively, our results indicate that MYO5B plays an important role in the differentiation of the normal intestinal epithelium and colon cancer cells, as well as a possible role in cancer progression promoting cell motility and invasion.
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Tyrrell, Graham Philip. „Modelling the myosin molecular motor“. Thesis, University of York, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247144.
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Thomas, Daniel G. „The self-interaction of myosin“. Thesis, University of Leicester, 1992. http://hdl.handle.net/2381/35170.
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The first event in thick filament formation must be the interaction of one myosin monomer with another to give a dimer. The energetics of the parallel apposition of the rod portion of myosin were first considered by McLachlan and Karn (Nature 299: 226-231, 1982; J. Mol. Biol. 164: 605-626, 1983). They applied a simple 'point scoring' algorithm to the periodic charge distribution of the myosin rod and suggested that there are peaks in interaction energy when the stagger between parallel rods is close to 14.3 and 43nm. We have modelled the assembly process on a more detailed basis in an attempt to understand the factors governing the structure of the thick filament. We have taken into account both the hydrodynamic and electrostatic properties of myosin. It is likely that the final state of parallel apposition of the monomers is reached via intermediate states. We identify as a likely intermediate a structure in which two monomers are bound at a single point contact to form an extended dimer, and have computed the likelihoods of formation and the stabilities of different forms of this structure. We have also computed the energetics of the pathways leading to the more stable parallel dimer. Our results suggest that selectivity for a 14.3 nm axial stagger is inherent in the pathway for dimerisation but that it is a consequence of the kinetics rather than the energetics of the assembly process. We have identified rat cardiac myosin at minimal ionic strength as a system in which later steps in the assembly process are blocked; small myosin oligomers become stable structures rather than transient intermediates and so can be trapped and characterised. The structures found are in both qualitative and quantitative agreement with the computational predictions.
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Carrington, Glenn Stuart Peter. „The flexibility of myosin 7a“. Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/22504/.
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Myosin 7a is a molecular motor found in hair cells of the ear and the photoreceptor cells of the eye. Myosin 7a is comprised of an actin-binding motor domain, a lever; which is composed of 5 IQ motifs that can potentially bind 5 light chains followed by a single alpha helical (SAH) domain, and a tail composed of 2 MyTH4-FERM domains. The lever is an essential mechanical element in myosin 7a function, but an understanding of its mechanical properties and how these derive from its substructure is lacking. It has been observed in vitro that myosin 7a is able to regulate its activity through a head-tail interaction. How the flexibility of the sub-domains of the lever allows the molecule to fold up is not completely understood. To address this, the first aim of this study was to look for evidence of novel light chain binding partners in myosin 7a, which revealed calmodulin to be the preferred light chain. My second aim was to study the structure and flexibility of the lever of full-length myosin 7a using single-particle image processing of images from negative stain electron microscopy (EM). Image averaging revealed the lever to be much shorter than expected. Additionally, there was evidence of thermally-driven flexing at the motor-lever junction. A stiffness of 78 pN.nm.rad-2 for the flexing was inferred, which represents a significant compliance in the head. An investigation into lever bending analysis, by monitoring the decay of tangent-tangent correlations of the lever shapes, yielded a persistence length of 38 ± 3 nm. Finally, long time molecular dynamics (MD) simulations were compared with a novel coarse-grained (CG) simulation technique called Fluctuating Finite Element Analysis (FFEA), which treats proteins as visco-elastic continua subject to thermal noise to probe the flexibility of myosin 7a. FFEA allows sufficiently long time simulations that are computationally less expensive than corresponding all-atom MD simulations to allow myosin 7a to explore its full range of configurations. Extraction of flexibility data from all-atom MD simulations calculated the bending stiffness of the SAH domain to be 60.5 pN.nm2, with reasonable overlap of the major modes of motion between the all-atom and CG simulation types.
Bücher zum Thema "Myosin A"
1
Sellers, James R. Motor proteins 2: myosin. London: Academic Press, 1995.
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Myosins. 2. Aufl. Oxford: Oxford University Press, 1999.
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Syrový, Ivo. Kontraktilní bílkoviny a funkční požadavky svalu. Praha: Academia, 1985.
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4
1933-, Sugi Haruo, und Pollack Gerald H, Hrsg. Mechanism of myofilament sliding in muscle contraction. New York: Plenum Press, 1993.
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Griffiths, Hazel Sylvia. Studies on the properties and function of myosin light chain kinase. Birmingham: University of Birmingham, 1986.
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Thomas, D. D. Molecular Interactions of Actin: Actin-Myosin Interaction and Actin-Based Regulation. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002.
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Keane, Anita M. Peptide mimetics of an actin-binding site on the myosin head. Birmingham: University of Birmingham, 1991.
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Milankov, Kosta. Immunocytochemical localization of actin and myosin within interphase nuclei in situ. Ottawa: National Library of Canada, 1993.
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Epp, Trevor Allan. Characterization of the human cardiac gas-myosin heavy chain gene. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1993.
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Eastwood, Anthony Michael. The use of peptide mimetics in defining the actin-myosin interaction. Birmingham: University of Birmingham, 1994.
Den vollen Inhalt der Quelle findenBuchteile zum Thema "Myosin A"
1
Gewies, Andreas, Jürgen Ruland, Alexey Kotlyarov, Matthias Gaestel, Shiri Procaccia, Rony Seger, Shin Yasuda et al. „Myosin II, “Conventional” Myosin“. In Encyclopedia of Signaling Molecules, 1169. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-0461-4_100886.
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Lackner, K. J., und D. Peetz. „Myosin“. In Lexikon der Medizinischen Laboratoriumsdiagnostik, 1. Berlin, Heidelberg: Springer Berlin Heidelberg, 2018. http://dx.doi.org/10.1007/978-3-662-49054-9_2210-1.
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Lackner, K. J., und D. Peetz. „Myosin“. In Springer Reference Medizin, 1711. Berlin, Heidelberg: Springer Berlin Heidelberg, 2019. http://dx.doi.org/10.1007/978-3-662-48986-4_2210.
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Ward, Tony Milford. „Myosin“. In Proteins and Tumour Markers May 1995, 1286–87. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-011-0681-8_54.
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Aitchison Smith, David. „Myosin Motors“. In The Sliding-Filament Theory of Muscle Contraction, 237–91. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-03526-6_6.
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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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Bugyi, Beáta, und András Kengyel. „Myosin XVI“. In Advances in Experimental Medicine and Biology, 405–19. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38062-5_18.
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Taft, Manuel H., und Sharissa L. Latham. „Myosin XVIII“. In Advances in Experimental Medicine and Biology, 421–38. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38062-5_19.
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Sweeney, H. Lee, Anne Houdusse und Julien Robert-Paganin. „Myosin Structures“. In Advances in Experimental Medicine and Biology, 7–19. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38062-5_2.
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Bocanegra, Jennifer L., Rebecca Adikes und Omar A. Quintero. „Myosin XIX“. In Advances in Experimental Medicine and Biology, 439–51. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-38062-5_20.
Der volle Inhalt der QuelleKonferenzberichte zum Thema "Myosin A"
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Egan, Paul F., Philip R. LeDuc, Jonathan Cagan und Christian Schunn. „A Design Exploration of Genetically Engineered Myosin Motors“. In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-48568.
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As technology advances, there is an increasing need to reliably output mechanical work at smaller scales. At the nanoscale, one of the most promising routes is utilizing biomolecular motors such as myosin proteins commonly found in cells. Myosins convert chemical energy into mechanical energy and are strong candidates for use as components of artificial nanodevices and multi-scale systems. Isoforms of the myosin superfamily of proteins are fine-tuned for specific cellular tasks such as intracellular transport, cell division, and muscle contraction. The modular structure that all myosins share makes it possible to genetically engineer them for fine-tuned performance in specific applications. In this study, a parametric analysis is conducted in order to explore the design space of Myosin II isoforms. The crossbridge model for myosin mechanics is used as a basis for a parametric study. The study sweeps commonly manipulated myosin performance variables and explores novel ways of tuning their performance. The analysis demonstrates the extent that myosin designs are alterable. Additionally, the study informs the biological community of gaps in experimentally tabulated myosin design parameters. The study lays the foundation for further progressing the design and optimization of individual myosins, a pivotal step in the eventual utilization of custom-built biomotors for a broad range of innovative nanotechnological devices.
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Egan, Paul F., Jonathan Cagan, Christian Schunn und Philip R. LeDuc. „Design of Complex Nano-Scale Systems Using Multi-Agent Simulations and Structure-Behavior-Function Representations“. In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-70291.
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Recent trends in technology are challenging engineers to configure products at ever smaller scales. At the nano-scale, biological protein machines are commonly chosen as a power-source for a broad-range of nano-devices. This paper explores the challenges in designing these and similar systems, such as improving the emergent system performance that arises from the interactions of many stochastic components. We develop a domain-independent methodology, using multi-agent simulations as a means of modeling and predicting emergent system behavior across scales and structure-behavior-function representations for understanding and navigating the resulting design space. This methodology is validated with an application of synthetic myosin motor design at the nanoscale, with simulation results aligning well with the macroscopic performance of myosin-powered muscular contractions. The multi-agent simulation is implemented with myosins modeled as agents, allowing for the virtual design and experimentation of synthetic myosins with altered structures and mechanochemical behaviors. Four myosin populations are designed and simulated, with their emergent system performance determined by aggregating the contributions of each myosin agent over time. Although the multi-agent simulation successfully recreates the emergent behaviors of the myosins, it is difficult to draw conclusions about how each structural variation influences aggregate performance. SBF representations of the system are then developed to describe how the aggregate performance of the system is explainable in terms of myosin behaviors, which map directly to altered myosin structures. It is then demonstrated how an engineer may utilize these representations and experimental results to reason about, and configure a myosin system with optimal performance. The methodology is domain-independent, ensuring its extendibility to similar complex systems while aiding a designer in simplifying a complex physical phenomenon to a design space consisting of only a few critical parameters. The methodology is particularly suited for complex systems with many parts operating stochastically across scales, and should prove invaluable for engineers facing the challenges of biological nanoscale design, where designs with unique properties require novel approaches or useful configurations in nature await discovery.
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Aprodu, Iuliana, Alberto Redaelli, Franco Maria Montevecchi und Monica Soncini. „Mechanical Characterization of Myosin II, Actin and Their Complexes by Molecular Mechanics Approach“. In ASME 8th Biennial Conference on Engineering Systems Design and Analysis. ASMEDC, 2006. http://dx.doi.org/10.1115/esda2006-95670.
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The knowledge of the mechanical properties of myosin and actin is of a crucial importance in order to better understand the molecular mechanism of sliding force generation in muscle contraction. The aim of our work was to realize a mechanical characterization of myosin II and actin monomer using the molecular mechanics approach, by assessing the elastic properties of the two proteins, and by establishing the interaction forces between the two monomers of the actomyosin complex, and between myosin’s scissure and adenine nucleotides (ATP and ADP). A restraining method was used in order to modify the axial length of the proteins or the intermolecular distances. The interaction force and the stiffness were calculated as first and second order derivative of the potential energy with respect to the applied elongation and intermolecular distance respectively. According to our results, the values of elastic modulus of myosin motor domain and actin are 0.48 GPa, and 0.13 GPa respectively, and myosin-ATP complex is characterized by an attraction force of 130 pN which is twofold greater than the interaction force between myosin and ADP. As for the actomyosin complex, the interaction force has a maximum value of 180 pN. The results of our simulations comply with theoretical and experimental remarks about mechanical properties of myosin II, actin, and their complex.
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Daniel, J. L., und M. Rigmaiden. „Evidence for Ca2+-independent phosphorylation of human platelet myosin“. In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644527.
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Phosphorylation of platelet myosin is thought to be required for activation of the contractile events occurring during platelet activation. At present the only known mechanism for Onitiating myosin phosphorylation is through a Ca2+-calmodulin-dependent activation of myosin light chain kinase. However, our previous studies using the fluorescent Ca2+-indicator quin2 indicated that both platelet shape change and myosin phosphorylation could be induced in an EGTA-containing media in the absence of a measurable change in cytosolic free Ca2+ concentration (Hallam, Daniel, Kendrick-Jones & Rink. Biochem. J. 232 (1985) 373). In order to confirm this finding, we fyave investigated the regulation of myosin phosphorylation usin^+a preparation of electrically-permeabilized platelets and Ca2+ buffers to control the internal Ca2+ concentration. Fifty percent myosin phosphorylation was obtained at 700 nM Ca2+. When thrombin (5 U/ml) was added to this system, this curve shifted both to the left and upward; 50% myosin phosphorylation was obtained at 400 nM Ca2+.A synthetic inhibitor of protein kinase C, H7, had no effect on myosin phosphorylation in the absence of agonist but did inhibit the thrombin-induced shift to left suggesting that protein kinase C may modulate myosin phosphorylation. We also compared the effects of H7 agonist-induced myosin phosphorylation and shape change in control and an quin2 loaded platelets. Comparable inhibition of both phosphorylation and the rate of shape change was observed with both quin2 and H7. Addition of H7 to quin2-loaded platelets resulted in complete inhibition of both agonist-induced shape change and myosin phosphorylation. These results indicate that both protein kinase C and Ca2+-dependent reactions are involved in complete expression of myosin phosphorylation in human platelets.
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Haghshenas-Jaryani, Mahdi, und Alan Bowling. „Multiscale Dynamic Modeling of Flexibility in Myosin V“. In ASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/detc2013-13154.
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This paper presents a multiscale dynamic model for the simulation and analysis of flexibility in myosin V. A three dimensional (3D) flexible multibody model is developed to mechanically model the biological structure of myosin V. Experimental studies have shown that myosin’s neck domain can be considered as three pairs of tandem elements which can bend at junctures between them. Therefore, each neck is modeled by three rigid bodies connected by flexible spherical joints. One of the most important issues in dynamic modeling of micro-nanoscale sized biological structures, likes DNA and motor proteins, is the long simulation run time due to the disproportionality between physical parameters involved in their dynamics such as mass, drag coefficient, and stiffness. In order to address this issue, the mostly used models, based on the famous overdamped Langevin dynamics, omit the inertial terms in the equations of motion; that leads to a first order model which is inconsistent with the Newton’s second law. However, the proposed model uses the concept of the method of multiple scales (MMS) that brings all terms of the equations of motion into proportion with each other that helps to retain the inertia terms. This keeps consistency of the model with the physical laws and increases time step size of numerical integration from commonly used sub-femto seconds to sub-milli seconds. Therefore, simulation run time will be many orders of magnitude less than ones based on the other approaches. The simulation results obtained by the proposed multiscale model show more realistic dynamic behavior of myosin V in compared with other models.
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Kostcheeva, O. I., V. Yu Ostchepkova, M. R. Sharipov, D. V. Stchepkin und G. V. Kopylova. „Influence of the myosin activator omecamptive-mecarbil onto the actin-myosin interaction in the myocard“. In VI Information school of a young scientist. Central Scientific Library of the Urals Branch of the Russian Academy of Sciences, 2018. http://dx.doi.org/10.32460/ishmu-2018-6-0023.
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Nikmaneshi, Mohammad Reza, Bahar Firoozabadi und Mohammad Said Saidi. „Continuum model of actin-myosin flow“. In 2013 20th Iranian Conference on Biomedical Engineering (ICBME). IEEE, 2013. http://dx.doi.org/10.1109/icbme.2013.6782200.
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LE GOFF, L., F. AMBLARD und E. M. FURST. „VISCOELASTICITY OF ACTIVE ACTIN-MYOSIN NETWORKS“. In Proceedings of the International Symposium. WORLD SCIENTIFIC, 2003. http://dx.doi.org/10.1142/9789812704931_0010.
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Bidone, Tamara Carla, Haosu Tang und Dimitrios Vavylonis. „Insights Into the Mechanics of Cytokinetic Ring Assembly Using 3D Modeling“. In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-39006.
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During fission yeast cytokinesis, actin filaments nucleated by cortical formin Cdc12 are captured by myosin motors bound to a band of cortical nodes. The myosin motors exert forces that pull nodes together into a contractile ring. Cross-linking interactions help align actin filaments and nodes into a single bundle. Mutations in the myosin motor domain and changes in the concentration of cross-linkers alpha-actinin and fimbrin alter the morphology of the condensing network, leading to clumps, rings or extended meshworks. How the contractile tension developing during ring formation depends on the interplay between network morphology, myosin motor activity, cross-linking and actin filament turnover remains to be elucidated. We addressed this question using a 3D computational model in which semiflexible actin filaments (represented as beads connected by springs) grow from formins, can be captured by myosin in neighboring nodes, and get cross-linked with one another through an attractive interaction. We identify regimes of tension generation between connected nodes under a wide set of conditions regarding myosin dynamics and strength of cross-linking between actin filaments. We find conditions that maximize circumferential tension, correlate them with network morphology and propose experiments to test these predictions. This work addresses “Morphogenesis of soft and living matter” using computational modeling to simulate cytokinetic ring assembly from the key molecular mechanisms of viscoelastic cross-linked actin networks that include active molecular motors.
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Chin, LY, Y. Bosse, PD Pare und CY Seow. „Myosin Filament Assembly in Airway Smooth Muscle.“ In American Thoracic Society 2009 International Conference, May 15-20, 2009 • San Diego, California. American Thoracic Society, 2009. http://dx.doi.org/10.1164/ajrccm-conference.2009.179.1_meetingabstracts.a2063.
Der volle Inhalt der QuelleBerichte der Organisationen zum Thema "Myosin A"
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Sadot, Einat, Christopher Staiger und Mohamad Abu-Abied. Studies of Novel Cytoskeletal Regulatory Proteins that are Involved in Abiotic Stress Signaling. United States Department of Agriculture, September 2011. http://dx.doi.org/10.32747/2011.7592652.bard.
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In the original proposal we planned to focus on two proteins related to the actin cytoskeleton: TCH2, a touch-induced calmodulin-like protein which was found by us to interact with the IQ domain of myosin VIII, ATM1; and ERD10, a dehydrin which was found to associate with actin filaments. As reported previously, no other dehydrins were found to interact with actin filaments. In addition so far we were unsuccessful in confirming the interaction of TCH2 with myosin VIII using other methods. In addition, no other myosin light chain candidates were found in a yeast two hybrid survey. Nevertheless we have made a significant progress in our studies of the role of myosins in plant cells. Plant myosins have been implicated in various cellular activities, such as cytoplasmic streaming (1, 2), plasmodesmata function (3-5), organelle movement (6-10), cytokinesis (4, 11, 12), endocytosis (4, 5, 13-15) and targeted RNA transport (16). Plant myosins belong to two main groups of unconventional myosins: myosin XI and myosin VIII, both closely related to myosin V (17-19). The Arabidopsis myosin family contains 17 members: 13 myosin XI and four myosin VIII (19, 20). The data obtained from our research of myosins was published in two papers acknowledging BARD funding. To address whether specific myosins are involved with the motility of specific organelles, we cloned the cDNAs from neck to tail of all 17 Arabidopsis myosins. These were fused to GFP and used as dominant negative mutants that interact with their cargo but are unable to walk along actin filaments. Therefore arrested organelle movement in the presence of such a construct shows that a particular myosin is involved with the movement of that particular organelle. While no mutually exclusive connections between specific myosins and organelles were found, based on overexpression of dominant negative tail constructs, a group of six myosins (XIC, XIE, XIK, XI-I, MYA1 and MYA2) were found to be more important for the motility of Golgi bodies and mitochondria in Nicotiana benthamiana and Nicotiana tabacum (8). Further deep and thorough analysis of myosin XIK revealed a potential regulation by head and tail interaction (Avisar et al., 2011). A similar regulatory mechanism has been reported for animal myosin V and VIIa (21, 22). In was shown that myosin V in the inhibited state is in a folded conformation such that the tail domain interacts with the head domain, inhibiting its ATPase and actinbinding activities. Cargo binding, high Ca2+, and/or phosphorylation may reduce the interaction between the head and tail domains, thus restoring its activity (23). Our collaborative work focuses on the characterization of the head tail interaction of myosin XIK. For this purpose the Israeli group built yeast expression vectors encoding the myosin XIK head. In addition, GST fusions of the wild-type tail as well as a tail mutated in the amino acids that mediate head to tail interaction. These were sent to the US group who is working on the isolation of recombinant proteins and performing the in vitro assays. While stress signals involve changes in Ca2+ levels in plants cells, the cytoplasmic streaming is sensitive to Ca2+. Therefore plant myosin activity is possibly regulated by stress. This finding is directly related to the goal of the original proposal.
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Sanders, Luraynne. Cell Adhesion, Signaling and Myosin in Breast Cancer. Fort Belvoir, VA: Defense Technical Information Center, August 2000. http://dx.doi.org/10.21236/ada392857.
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Sanders, Luraynne C. Cell Adhesion, Signaling and Myosin in Breast Cancer. Fort Belvoir, VA: Defense Technical Information Center, August 1999. http://dx.doi.org/10.21236/ada382496.
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Chew, Teng-Leong. Regulation of Actin-Myosin Cytoskeletal Changes Involved in Cancer Metastasis. Fort Belvoir, VA: Defense Technical Information Center, Juli 2001. http://dx.doi.org/10.21236/ada396798.
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Hofmann, Wilma A. The Role of a Novel Myosin Isoform in Prostate Cancer Metastasis. Fort Belvoir, VA: Defense Technical Information Center, Oktober 2013. http://dx.doi.org/10.21236/ada593300.
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Zhang, John Q. Post-Myocardial Infarction and Exercise Training on Myosin Heavy Chain and Cardiac Function. Science Repository, April 2019. http://dx.doi.org/10.31487/j.jicoa.2019.01.08.
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Schiefelbein, J. Molecular genetics of myosin motors in Arabidopsis. Final report, July 1, 1992--June 30, 1996. Office of Scientific and Technical Information (OSTI), Februar 1997. http://dx.doi.org/10.2172/486111.
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Staiger, Christopher. Regulation of Cell Wall Assembly: Myosin and Exocyst Involvement in Cellulose Synthase Delivery to the Plasma Membrane. Office of Scientific and Technical Information (OSTI), Januar 2022. http://dx.doi.org/10.2172/1840725.
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Gabaix, Xavier, und David Laibson. Myopia and Discounting. Cambridge, MA: National Bureau of Economic Research, März 2017. http://dx.doi.org/10.3386/w23254.
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Angeletos, George-Marios, und Zhen Huo. Myopia and Anchoring. Cambridge, MA: National Bureau of Economic Research, April 2018. http://dx.doi.org/10.3386/w24545.
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