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Zeitschriftenartikel zum Thema „Myosine A“

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1

PICARD, B., L. LEFAUCHEUR, B. FAUCONNEAU, H. REMIGNON, Y. CHEREL, E. BARREY und J. NEDELEC. „Dossier : Caractérisation des différents types de fibres musculaires dans plusieurs espèces : production et utilisation d’anticorps monoclonaux dirigés contre les chaînes lourdes de myosine rapide IIa et IIb“. INRAE Productions Animales 11, Nr. 2 (02.04.1998): 145–63. http://dx.doi.org/10.20870/productions-animales.1998.11.2.3926.

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Des anticorps monoclonaux dirigés contre les chaînes lourdes de myosine (MHC : myosin heavy chain) de différentes espèces d’animaux : bovin, porc, poisson, poulet, dinde, cheval ont été produits. Ils ont été testés par immunohistologie sur des coupes de muscle squelettique chez le bovin, le porc, le poisson, le poulet et la dinde et par ELISA chez le cheval. Les différents anticorps retenus dans ce projet permettent de nouvelles applications pour l’étude du muscle squelettique. En particulier deux anticorps monoclonaux peuvent être utilisés pour classer par immunohistologie les fibres IIA et IIB : l’un reconnaissant les MHC I et IIb chez le bovin et le cheval et les MHC I, IIb et IIx chez le porc, l’autre reconnaissant les MHC IIa et IIx chez le porc. D’autres anticorps ont permis de révéler une hétérogénéité dans la composition en myosine des fibres des muscles blanc et rouge de poisson, mais également dans la composition en myosine rapide des muscles de poulet et de dinde, sans toutefois permettre dans ces deux espèces une distinction précise des fibres IIA et IIB. De plus, chez la truite arc-en-ciel, un anticorps réagit plus spécifiquement contre les myosines des petites fibres témoins d’une myogénèse de novo dans le muscle blanc. Cependant il n’a pas été possible d’obtenir des anticorps spécifiques des fibres IIA et IIB utilisables en particulier en dosage ELISA ; cette obtention demeure un objectif important pour la poursuite des travaux.

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CASSAR-MALEK, I., A. LISTRAT und B. PICARD. „Contrôle hormonal des caractéristiques des fibres musculaires après la naissance“. INRAE Productions Animales 11, Nr. 5 (06.12.1998): 365–77. http://dx.doi.org/10.20870/productions-animales.1998.11.5.3965.

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Après la naissance, la croissance et les propriétés contractiles et métaboliques des fibres musculaires sont soumises à une régulation endocrinienne complexe. A l’exception des glucocorticoïdes, la plupart des hormones présente une action anabolique sur le tissu musculaire. Leur influence sur les caractéristiques des fibres est cependant très différente. Ainsi, les hormones somatotropes affectent peu la composition en fibres des muscles. La GH, comme l’IGF-1, régulerait cependant l’expression des isoformes de myosine. Les hormones thyroïdiennes augmentent la proportion des fibres rapides au détriment des lentes. Elles régulent l’expression des chaînes lourdes de myosine, en augmentant celles des isoformes rapides. L’insuline joue également un rôle important, le diabète s’accompagnant d’une diminution du pourcentage relatif des fibres rapides glycolytiques et de la quantité des myosines natives rapides. Les agonistes béta-adrénergiques des catécholamines augmentent la proportion des fibres rapides IIB au détriment des lentes. Leur influence sur l’expression des myosines reste toutefois peu connue. L’action des stéroïdes sexuels est par contre bien documentée : les androgènes diminuent la proportion des fibres rapides IIB, et l’accumulation des chaînes lourdes de myosine IIb. Les oestrogènes ont peu d’effets reconnus sur ces caractéristiques. Enfin, si les fibres IIB constituent la principale cible des glucocorticoïdes, leur effet sur les caractéristiques des fibres est encore mal connu. L’ensemble de ces données suggère que l’on peut modifier la croissance du muscle et sa composition en fibres en modifiant l’équilibre endocrinien des animaux par les techniques d’élevage.

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Lecarpentier, Y., JC Lambry, D. Chemla und C. Coirault. „La myosine, moteur moléculaire musculaire.“ médecine/sciences 14, Nr. 10 (1998): 1077. http://dx.doi.org/10.4267/10608/913.

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Ménétrey, Julie, Amel Bahloul und Anne Houdusse. „Une myosine à contre-sens“. médecine/sciences 22, Nr. 2 (Februar 2006): 120–22. http://dx.doi.org/10.1051/medsci/2006222120.

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5

JURIE, C., J. NÉDELEC und B. PICARD. „Production des anticorps monoclonaux spécifiques des chaînes lourdes de myosine“. INRAE Productions Animales 11, Nr. 2 (02.04.1998): 146–49. http://dx.doi.org/10.20870/productions-animales.1998.11.2.3927.

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Cet article fait partie du dossier : Caractérisation des différents types de fibres musculaires dans plusieurs espèces : production et utilisation d’anticorps monoclonaux dirigés contre les chaînes lourdes de myosine rapide IIa et IIb

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PICARD, B., und M. DURIS. „Caractérisation des chaînes lourdes de myosine dans le muscle de bovin“. INRAE Productions Animales 11, Nr. 2 (02.04.1998): 150–52. http://dx.doi.org/10.20870/productions-animales.1998.11.2.3928.

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Cet article fait partie du dossier : Caractérisation des différents types de fibres musculaires dans plusieurs espèces : production et utilisation d’anticorps monoclonaux dirigés contre les chaînes lourdes de myosine rapide IIa et IIb

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LEFAUCHEUR, L., und P. ECOLAN. „Composition en chaînes lourdes de myosine des fibres musculaires de type II chez le porc“. INRAE Productions Animales 11, Nr. 2 (02.04.1998): 152–54. http://dx.doi.org/10.20870/productions-animales.1998.11.2.3929.

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Cet article fait partie du dossier : Caractérisation des différents types de fibres musculaires dans plusieurs espèces : production et utilisation d’anticorps monoclonaux dirigés contre les chaînes lourdes de myosine rapide IIa et IIb

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RÉMIGNON, H., und V. DESROSIERS. „Recherche d’anticorps dirigés contre les différents types de fibres chez le poulet“. INRAE Productions Animales 11, Nr. 2 (02.04.1998): 157–59. http://dx.doi.org/10.20870/productions-animales.1998.11.2.3931.

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Cet article fait partie du dossier : Caractérisation des différents types de fibres musculaires dans plusieurs espèces: production et utilisation d’anticorps monoclonaux dirigés contre les chaînes lourdes de myosine rapide IIa et IIb

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CHEREL, Y., L. GUIGAND und M. WYERS. „Anticorps anti-chaînes lourdes de myosine : outils d’étude de la régénération musculaire dans l’espèce dinde“. INRAE Productions Animales 11, Nr. 2 (02.04.1998): 159–60. http://dx.doi.org/10.20870/productions-animales.1998.11.2.3932.

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Cet article fait partie du dossier : Caractérisation des différents types de fibres musculaires dans plusieurs espèces: production et utilisation d’anticorps monoclonaux dirigés contre les chaînes lourdes de myosine rapide IIa et IIb

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BARREY, E., J. P. VALETTE und M. JOUGLIN. „Analyse de la composition en chaînes lourdes de myosine chez le cheval : application la sélection du cheval de course“. INRAE Productions Animales 11, Nr. 2 (02.04.1998): 160–63. http://dx.doi.org/10.20870/productions-animales.1998.11.2.3933.

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Cet article fait partie du dossier : Caractérisation des différents types de fibres musculaires dans plusieurs espèces: production et utilisation d’anticorps monoclonaux dirigés contre les chaînes lourdes de myosine rapide IIa et IIb

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Syamaladevi, Divya P., Margaret S. Sunitha, S. Kalaimathy, Chandrashekar C. Reddy, Mohammed Iftekhar, Shaik N. Pasha und R. Sowdhamini. „Myosinome: A Database of Myosins from Select Eukaryotic Genomes to Facilitate Analysis of Sequence-Structure-Function Relationships“. Bioinformatics and Biology Insights 6 (Januar 2012): BBI.S9902. http://dx.doi.org/10.4137/bbi.s9902.

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Myosins are one of the largest protein superfamilies with 24 classes. They have conserved structural features and catalytic domains yet show huge variation at different domains resulting in a variety of functions. Myosins are molecules driving various kinds of cellular processes and motility until the level of organisms. These are ATPases that utilize the chemical energy released by ATP hydrolysis to bring about conformational changes leading to a motor function. Myosins are important as they are involved in almost all cellular activities ranging from cell division to transcriptional regulation. They are crucial due to their involvement in many congenital diseases symptomatized by muscular malfunctions, cardiac diseases, deafness, neural and immunological dysfunction, and so on, many of which lead to death at an early age. We present Myosinome, a database of selected myosin classes (myosin II, V, and VI) from five model organisms. This knowledge base provides the sequences, phylogenetic clustering, domain architectures of myosins and molecular models, structural analyses, and relevant literature of their coiled-coil domains. In the current version of Myosinome, information about 71 myosin sequences belonging to three myosin classes (myosin II, V, and VI) in five model organisms ( Homo Sapiens, Mus musculus, D. melanogaster, C. elegans and S. cereviseae) identified using bioinformatics surveys are presented, and several of them are yet to be functionally characterized. As these proteins are involved in congenital diseases, such a database would be useful in short-listing candidates for gene therapy and drug development. The database can be accessed from http://caps.ncbs.res.in/myosinome .

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Coudrier, Evelyne, und Olga Iuliano. „Une myosine non conventionnelle contrôle la formation de l’axone“. médecine/sciences 35, Nr. 1 (Januar 2019): 16–18. http://dx.doi.org/10.1051/medsci/2018315.

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Frédéricq, Eugène. „Fonction et réactions des groupes sulfhydryles de la myosine“. Bulletin des Sociétés Chimiques Belges 54, Nr. 1 (01.09.2010): 265–76. http://dx.doi.org/10.1002/bscb.19450540121.

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14

Trybus, KM, GS Waller und TA Chatman. „Coupling of ATPase activity and motility in smooth muscle myosin is mediated by the regulatory light chain“. Journal of Cell Biology 124, Nr. 6 (15.03.1994): 963–69. http://dx.doi.org/10.1083/jcb.124.6.963.

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Smooth muscle myosin acts as a molecular motor only if the regulatory light chain (RLC) is phosphorylated. This subunit can be removed from myosin by a novel method involving the use of trifluoperazine. The motility of RLC-deficient myosin is very slow, but native properties are restored when RLC is rebound. Truncating 6 residues from the COOH terminus of the RLC had no effect on phosphorylated myosin's motor properties, while removal of the last 12 residues reduced velocity by approximately 30%. Very slow movement was observed once 26 residues were deleted, or with myosin containing only the COOH-terminal RLC domain. These two mutants thus mimicked the behavior of RLC-deficient myosin, with the important difference that the mutant myosins were monodisperse when assayed by sedimentation velocity and electron microscopy. The decreased motility therefore cannot be caused by aggregation. A common feature of RLC-deficient myosin and the mutant myosins that moved actin slowly was an increased myosin ATPase compared with dephosphorylated myosin, and a lower actin-activated ATPase than obtained with phosphorylated myosin. These results suggest that the COOH-terminal portion of an intact RLC is involved in interactions that regulate myosin's "on-off" switch, both in terms of completely inhibiting and completely activating the molecule.

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Orsetti, A., JF Brun, O. Bouix, D. Rama, I. Supparo, C. Larue, C. Calzolari, MC Lagrange und C. Heinen. „Les fragments de myosine, marqueurs de l'état fonctionnel du muscle“. Science & Sports 8, Nr. 1 (Januar 1993): 23–24. http://dx.doi.org/10.1016/s0765-1597(05)80077-2.

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16

Weil, Dominique, Gallia Levy, Iman Sahly, Fabienne Lévi-Acobas, Stéphane Blanchard, Fabien Crozet, Josseline Kaplan et al. „Syndrome de Usher de type IB : Anomalie d'une myosine non conventionnelle“. Annales de l'Institut Pasteur / Actualités 6, Nr. 4 (Januar 1995): 300–303. http://dx.doi.org/10.1016/0924-4204(96)83387-7.

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Steinacker, J. M., W. Lormes, C. Simsch, P. Jehle, K. G. Petersen, B. O. B??hm, M. Lehmann und Y. Liu. „MYOSINE HEAVY-CHAIN EXPRESSION AND SOMATOTROPIC HORMONES DURING EXHAUSTING TRAINING IN ROWERS“. Medicine & Science in Sports & Exercise 33, Nr. 5 (Mai 2001): S186. http://dx.doi.org/10.1097/00005768-200105001-01049.

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18

Alonso, Florian, Pirjo Spuul, IJsbrand Kramer und Elisabeth Génot. „Variations sur le thème des podosomes, une affaire de contexte“. médecine/sciences 34, Nr. 12 (Dezember 2018): 1063–70. http://dx.doi.org/10.1051/medsci/2018296.

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Les podosomes sont des microdomaines membranaires riches en actine, en interaction directe avec la matrice extracellulaire. Des câbles d’acto-myosine les assemblent en réseau pour former une superstructure cellulaire aux fonctions versatiles. Extensivement décrits in vitro, les podosomes se dessinent comme des acteurs majeurs de processus physiologiques spécifiques. Les détails de leur intervention in vivo restent à préciser. Le microenvironnement ayant un effet prépondérant dans l’acquisition de leurs caractéristiques morphologiques et fonctionnelles, leur rôle ne peut être abordé que dans un contexte cellulaire particulier. Nous nous focaliserons ici sur trois processus impliquant ces structures et discuterons les propriétés des podosomes exploitées dans ces situations.

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Vuillez, J. P., M. D. Brunet, E. Borrel, J. L. Bosson, M. J. Stasia, P. Eymerit, I. Perez und D. Blin. „Place du dosage immunoradiométrique de la chaîne lourde de la myosine en chirurgie coronarienne“. Immuno-analyse & Biologie Spécialisée 11, Nr. 1 (Januar 1996): 38–42. http://dx.doi.org/10.1016/0923-2532(96)88389-x.

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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.

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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.

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Petit, C. „Une myosine non conventionnelle à l'origine de l'une des formes génétiques du syndrome de Usher“. médecine/sciences 11, Nr. 8 (1995): 1181. http://dx.doi.org/10.4267/10608/2436.

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GARDAHAUT, Marie-France, A. KHASKIYE, T. ROUAUD, D. RENAUD und G. LE DOUARIN. „Innervation, rythme d'activité et accumulation des chaînes légères de myosine d'un muscle rapide de poulet“. Reproduction Nutrition Développement 28, Nr. 3B (1988): 773–80. http://dx.doi.org/10.1051/rnd:19880511.

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R., M. „La myosine 5a est un substrat de Akt2 qui intervient dans la translocation de GLUT4“. Médecine des Maladies Métaboliques 1, Nr. 3 (September 2007): 94. http://dx.doi.org/10.1016/s1957-2557(07)92010-6.

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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.

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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.

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Morin, Morgane, Hadia Moindjie und Clara Nahmias. „Le transport mitochondrial“. médecine/sciences 38, Nr. 6-7 (Juni 2022): 585–93. http://dx.doi.org/10.1051/medsci/2022085.

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La reprogrammation métabolique est l’un des marqueurs de la carcinogenèse. Au cœur de cette reprogrammation se trouvent les mitochondries qui produisent l’énergie sous forme de molécules d’ATP. La régulation spatio-temporelle de la production d’ATP, indispensable pour fournir l’énergie au bon endroit et au bon moment, est assurée par le transport intracellulaire des mitochondries. Les complexes Miro/TRAK présents à la surface des mitochondries se lient aux protéines motrices de la cellule (dynéine, kinésine, myosine) pour transporter les mitochondries le long du cytosquelette. Ces acteurs du transport mitochondrial sont souvent dérégulés dans le cancer. Nous présentons dans cette revue les mécanismes par lesquels le transport mitochondrial contribue à la migration, à la division cellulaire et à la réponse au stress des cellules cancéreuses. Décrypter ces mécanismes pourrait ouvrir la voie à de nouvelles approches thérapeutiques en oncologie.

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Hagège, A. „Les modulateurs de la myosine cardiaque révolutionnent la prise en charge de la cardiomyopathie hypertrophique obstructive“. Archives des Maladies du Coeur et des Vaisseaux - Pratique 2021, Nr. 296 (März 2021): 3–5. http://dx.doi.org/10.1016/j.amcp.2020.12.006.

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Duracher, C., C. Coirault, F. X. Blanc, P. Y. Gueugniaud, J. S. David, B. Riou und Y. Lecarpentier. „236 Effets de l’isoflurane sur les interactions actine-myosine de trachée de rats Fisher et Lewis“. Revue des Maladies Respiratoires 21 (Januar 2004): 91. http://dx.doi.org/10.1016/s0761-8425(04)71862-8.

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Jacquemin, V., A. Bigot, D. Furling, G. Butler-Browne und V. Mouly. „L'IGF-1 induit une augmentation de la taille et du contenu en myosine des myotubes humains“. Science & Sports 20, Nr. 4 (August 2005): 199–201. http://dx.doi.org/10.1016/j.scispo.2005.01.011.

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Larue, C., C. Calzolari, M. C. Lagrange, C. Heinen, Joc Léger, J. Léger und B. Pau. „Intérêt du dosage de la myosine dans le diagnostic et le suivi de l'infarctus du myocarde“. Immuno-analyse & Biologie Spécialisée 4, Nr. 6 (Dezember 1989): 49–54. http://dx.doi.org/10.1016/s0923-2532(89)80007-9.

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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.

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Yumura, Shigehiko, und Taro Q. P. Uyeda. „Transport of Myosin II to the Equatorial Region without Its Own Motor Activity in Mitotic Dictyostelium Cells“. Molecular Biology of the Cell 8, Nr. 10 (Oktober 1997): 2089–99. http://dx.doi.org/10.1091/mbc.8.10.2089.

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Fluorescently labeled myosin moved and accumulated circumferentially in the equatorial region of dividingDictyostelium cells within a time course of 4 min, followed by contraction of the contractile ring. To investigate the mechanism of this transport process, we have expressed three mutant myosins that cannot hydrolyze ATP in myosin null cells. Immunofluorescence staining showed that these mutant myosins were also correctly transported to the equatorial region, although no contraction followed. The rates of transport, measured using green fluorescent protein-fused myosins, were indistinguishable between wild-type and mutant myosins. These observations demonstrate that myosin is passively transported toward the equatorial region and incorporated into the forming contractile ring without its own motor activity.

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Shu, S., R. J. Lee, J. M. LeBlanc-Straceski und T. Q. Uyeda. „Role of myosin II tail sequences in its function and localization at the cleavage furrow in Dictyostelium“. Journal of Cell Science 112, Nr. 13 (01.07.1999): 2195–201. http://dx.doi.org/10.1242/jcs.112.13.2195.

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Cytoplasmic myosin II accumulates in the cleavage furrow and provides the force for cytokinesis in animal and amoeboid cells. One model proposes that a specific domain in the myosin II tail is responsible for its localization, possibly by interacting with a factor concentrated in the equatorial region. To test this possibility, we have expressed myosins carrying mutations in the tail domain in a strain of Dictyostelium cells from which the endogenous myosin heavy chain gene has been deleted. The mutations used in this study include four internal tail deletions: Mydelta824-941, Mydelta943-1464, Mydelta943-1194 and Mydelta1156-1464. Contrary to the prediction of the hypothesis, immunofluorescence staining demonstrated that all mutant myosins were able to move toward the furrow region. Chimeric myosins, which consisted of a Dictyostelium myosin head and chicken skeletal myosin tail, also efficiently localized to the cleavage furrow. All these deletion and chimeric mutant myosins, except for Mydelta943-1464, the largest deletion mutant, were able to support cytokinesis in suspension. Our data suggest that there is no single specific domain in the tail of Dictyostelium myosin II that is required for its functioning at and localization to the cleavage furrow.

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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.

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Kiehart, D. P., und R. Feghali. „Cytoplasmic myosin from Drosophila melanogaster.“ Journal of Cell Biology 103, Nr. 4 (01.10.1986): 1517–25. http://dx.doi.org/10.1083/jcb.103.4.1517.

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Myosin is identified and purified from three different established Drosophila melanogaster cell lines (Schneider's lines 2 and 3 and Kc). Purification entails lysis in a low salt, sucrose buffer that contains ATP, chromatography on DEAE-cellulose, precipitation with actin in the absence of ATP, gel filtration in a discontinuous KI-KCl buffer system, and hydroxylapatite chromatography. Yield of pure cytoplasmic myosin is 5-10%. This protein is identified as myosin by its cross-reactivity with two monoclonal antibodies against human platelet myosin, the molecular weight of its heavy chain, its two light chains, its behavior on gel filtration, its ATP-dependent affinity for actin, its characteristic ATPase activity, its molecular morphology as demonstrated by platinum shadowing, and its ability to form bipolar filaments. The molecular weight of the cytoplasmic myosin's light chains and peptide mapping and immunochemical analysis of its heavy chains demonstrate that this myosin, purified from Drosophila cell lines, is distinct from Drosophila muscle myosin. Two-dimensional thin layer maps of complete proteolytic digests of iodinated muscle and cytoplasmic myosin heavy chains demonstrate that, while the two myosins have some tryptic and alpha-chymotryptic peptides in common, most peptides migrate with unique mobility. One-dimensional peptide maps of SDS PAGE purified myosin heavy chain confirm these structural data. Polyclonal antiserum raised and reacted against Drosophila myosin isolated from cell lines cross-reacts only weakly with Drosophila muscle myosin isolated from the thoraces of adult Drosophila. Polyclonal antiserum raised against Drosophila muscle myosin behaves in a reciprocal fashion. Taken together our data suggest that the myosin purified from Drosophila cell lines is a bona fide cytoplasmic myosin and is very likely the product of a different myosin gene than the muscle myosin heavy chain gene that has been previously identified and characterized.

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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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38

Trivedi, Darshan V., Suman Nag, Annamma Spudich, Kathleen M. Ruppel und James A. Spudich. „The Myosin Family of Mechanoenzymes: From Mechanisms to Therapeutic Approaches“. Annual Review of Biochemistry 89, Nr. 1 (20.06.2020): 667–93. http://dx.doi.org/10.1146/annurev-biochem-011520-105234.

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Myosins are among the most fascinating enzymes in biology. As extremely allosteric chemomechanical molecular machines, myosins are involved in myriad pivotal cellular functions and are frequently sites of mutations leading to disease phenotypes. Human β-cardiac myosin has proved to be an excellent target for small-molecule therapeutics for heart muscle diseases, and, as we describe here, other myosin family members are likely to be potentially unique targets for treating other diseases as well. The first part of this review focuses on how myosins convert the chemical energy of ATP hydrolysis into mechanical movement, followed by a description of existing therapeutic approaches to target human β-cardiac myosin. The next section focuses on the possibility of targeting nonmuscle members of the human myosin family for several diseases. We end the review by describing the roles of myosin in parasites and the therapeutic potential of targeting them to block parasitic invasion of their hosts.

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Hamoir, G. „Albert Szent Gyorgyi, le découvreur de la vitamine C, de la myosine et de l'actomyosine (1893-1986)“. Bulletin de la Classe des sciences 73, Nr. 1 (1987): 131–39. http://dx.doi.org/10.3406/barb.1987.57665.

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40

Zangarelli, A., S. Walrand, C. Guillet, P. Gachon, P. Rousset, C. Giraudet und Y. Boirie. „Effet d’une supplémentation en leucine sur la vitesse de synthèse de la myosine au cours du vieillissement“. Cahiers de Nutrition et de Diététique 39, Nr. 1 (Februar 2004): 59. http://dx.doi.org/10.1016/s0007-9960(04)94356-8.

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41

Liu, Xiong, Shi Shu und Edward D. Korn. „Muscle myosins form folded monomers, dimers, and tetramers during filament polymerization in vitro“. Proceedings of the National Academy of Sciences 117, Nr. 27 (22.06.2020): 15666–72. http://dx.doi.org/10.1073/pnas.2001892117.

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Muscle contraction depends on the cyclical interaction of myosin and actin filaments. Therefore, it is important to understand the mechanisms of polymerization and depolymerization of muscle myosins. Muscle myosin 2 monomers exist in two states: one with a folded tail that interacts with the heads (10S) and one with an unfolded tail (6S). It has been thought that only unfolded monomers assemble into bipolar and side-polar (smooth muscle myosin) filaments. We now show by electron microscopy that, after 4 s of polymerization in vitro in both the presence (smooth muscle myosin) and absence of ATP, skeletal, cardiac, and smooth muscle myosins form tail-folded monomers without tail–head interaction, tail-folded antiparallel dimers, tail-folded antiparallel tetramers, unfolded bipolar tetramers, and small filaments. After 4 h, the myosins form thick bipolar and, for smooth muscle myosin, side-polar filaments. Nonphosphorylated smooth muscle myosin polymerizes in the presence of ATP but with a higher critical concentration than in the absence of ATP and forms only bipolar filaments with bare zones. Partial depolymerization in vitro of nonphosphorylated smooth muscle myosin filaments by the addition of MgATP is the reverse of polymerization.

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Petersen, Karl J., Holly V. Goodson, Ashley L. Arthur, G. W. Gant Luxton, Anne Houdusse und Margaret A. Titus. „MyTH4-FERM myosins have an ancient and conserved role in filopod formation“. Proceedings of the National Academy of Sciences 113, Nr. 50 (23.11.2016): E8059—E8068. http://dx.doi.org/10.1073/pnas.1615392113.

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The formation of filopodia in Metazoa and Amoebozoa requires the activity of myosin 10 (Myo10) in mammalian cells and of Dictyostelium unconventional myosin 7 (DdMyo7) in the social amoeba Dictyostelium. However, the exact roles of these MyTH4-FERM myosins (myosin tail homology 4-band 4.1, ezrin, radixin, moesin; MF) in the initiation and elongation of filopodia are not well defined and may reflect conserved functions among phylogenetically diverse MF myosins. Phylogenetic analysis of MF myosin domains suggests that a single ancestral MF myosin existed with a structure similar to DdMyo7, which has two MF domains, and that subsequent duplications in the metazoan lineage produced its functional homolog Myo10. The essential functional features of the DdMyo7 myosin were identified using quantitative live-cell imaging to characterize the ability of various mutants to rescue filopod formation in myo7-null cells. The two MF domains were found to function redundantly in filopod formation with the C-terminal FERM domain regulating both the number of filopodia and their elongation velocity. DdMyo7 mutants consisting solely of the motor plus a single MyTH4 domain were found to be capable of rescuing the formation of filopodia, establishing the minimal elements necessary for the function of this myosin. Interestingly, a chimeric myosin with the Myo10 MF domain fused to the DdMyo7 motor also was capable of rescuing filopod formation in the myo7-null mutant, supporting fundamental functional conservation between these two distant myosins. Together, these findings reveal that MF myosins have an ancient and conserved role in filopod formation.

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Holmes, K. C., D. R. Trentham, R. Simmons und Peter G. Gillespie. „Myosin I and adaptation of mechanical transduction by the inner ear“. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 359, Nr. 1452 (29.12.2004): 1945–51. http://dx.doi.org/10.1098/rstb.2004.1564.

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Twenty years ago, the description of hair-cell stereocilia as actin-rich structures led to speculation that myosin molecules participated in mechanical transduction in the inner ear. In 1987, Howard and Hudspeth proposed specifically that a myosin I might mediate adaptation of the transduction current carried by hair cells, the sensory cells of the ear. We exploited the myosin literature to design tests of this hypothesis and to show that the responsible isoform is myosin 1c. The identification of this myosin as the adaptation motor would have been impossible without thorough experimentation on other myosins, particularly muscle myosins. The sliding-filament hypothesis for muscle contraction has thus led to a detailed understanding of the behaviour of hair cells.

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Kolega, J. „Cytoplasmic dynamics of myosin IIA and IIB: spatial ‘sorting’ of isoforms in locomoting cells“. Journal of Cell Science 111, Nr. 15 (01.08.1998): 2085–95. http://dx.doi.org/10.1242/jcs.111.15.2085.

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Different isoforms of non-muscle myosin II have different distributions in vivo, even within individual cells. In order to understand how these different distributions arise, the distribution and dynamics of non-muscle myosins IIA and myosin IIB were examined in cultured cells using immunofluorescence staining and time-lapse imaging of fluorescent analogs. Cultured bovine aortic endothelia contained both myosins IIA and IIB. Both isoforms distributed along stress fibers, in linear or punctate aggregates within lamellipodia, and diffusely around the nucleus. However, the A isoform was preferentially located toward the leading edge of migrating cells when compared with myosin IIB by double immunofluorescence staining. Conversely, the B isoform was enriched in structures at the cells' trailing edges. When fluorescent analogs of the two isoforms were co-injected into living cells, the injected myosins distributed with the same disparate localizations as endogenous myosins IIA and IIB. This indicated that the ability of the myosins to ‘sort’ within the cytoplasm is intrinsic to the proteins themselves, and not a result of localized synthesis or degradation. Furthermore, time-lapse imaging of injected analogs in living cells revealed differences in the rates at which the two isoforms rearranged during cell movement. The A isoform appeared in newly formed structures more rapidly than the B isoform, and was also lost more rapidly when structures disassembled. These observations suggest that the different localizations of myosins IIA and IIB reflect different rates at which the isoforms transit through assembly, movement and disassembly within the cell. The relative proportions of different myosin II isoforms within a particular cell type may determine the lifetimes of various myosin II-based structures in that cell.

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Ruppel, K. M., und J. A. Spudich. „Structure-function studies of the myosin motor domain: importance of the 50-kDa cleft.“ Molecular Biology of the Cell 7, Nr. 7 (Juli 1996): 1123–36. http://dx.doi.org/10.1091/mbc.7.7.1123.

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We used random mutagenesis to create 21 point mutations in a highly conserved region of the motor domain of Dictyostelium myosin and classified them into three distinct groups based on the ability to complement myosin null cell phenotypes: wild type, intermediate, and null. Biochemical analysis of the mutated myosins also revealed three classes of mutants that correlated well with the phenotypic classification. The mutated myosins that were not fully functional showed defects ranging from ATP nonhydrolyzers to myosins whose enzymatic and mechanical properties are uncoupled. Placement of the mutations onto the three-dimensional structure of myosin showed that the mutated region lay along the cleft that separates the active site from the actin-binding domain and that has been shown to move in response to changes at the active site. These results demonstrate that this region of myosin plays a key role in transduction of chemical energy to mechanical displacement.

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Kurth, Elizabeth G., Valera V. Peremyslov, Hannah L. Turner, Kira S. Makarova, Jaime Iranzo, Sergei L. Mekhedov, Eugene V. Koonin und Valerian V. Dolja. „Myosin-driven transport network in plants“. Proceedings of the National Academy of Sciences 114, Nr. 8 (17.01.2017): E1385—E1394. http://dx.doi.org/10.1073/pnas.1620577114.

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We investigate the myosin XI-driven transport network inArabidopsisusing protein–protein interaction, subcellular localization, gene knockout, and bioinformatics analyses. The two major groups of nodes in this network are myosins XI and their membrane-anchored receptors (MyoB) that, together, drive endomembrane trafficking and cytoplasmic streaming in the plant cells. The network shows high node connectivity and is dominated by generalists, with a smaller fraction of more specialized myosins and receptors. We show that interaction with myosins and association with motile vesicles are common properties of the MyoB family receptors. We identify previously uncharacterized myosin-binding proteins, putative myosin adaptors that belong to two unrelated families, with four members each (MadA and MadB). Surprisingly, MadA1 localizes to the nucleus and is rapidly transported to the cytoplasm, suggesting the existence of myosin XI-driven nucleocytoplasmic trafficking. In contrast, MadA2 and MadA3, as well as MadB1, partition between the cytosolic pools of motile endomembrane vesicles that colocalize with myosin XI-K and diffuse material that does not. Gene knockout analysis shows that MadB1–4 contribute to polarized root hair growth, phenocopying myosins, whereas MadA1–4 are redundant for this process. Phylogenetic analysis reveals congruent evolutionary histories of the myosin XI, MyoB, MadA, and MadB families. All these gene families emerged in green algae and show concurrent expansions via serial duplication in flowering plants. Thus, the myosin XI transport network increased in complexity and robustness concomitantly with the land colonization by flowering plants and, by inference, could have been a major contributor to this process.

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Sparkes, Imogen A. „Motoring around the plant cell: insights from plant myosins“. Biochemical Society Transactions 38, Nr. 3 (24.05.2010): 833–38. http://dx.doi.org/10.1042/bst0380833.

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Organelle movement in plants cells is extremely dynamic. Movement is driven by the acto-myosin system. Higher plant myosins fall into two classes: classes XI and VIII. Localization studies have highlighted that myosins are present throughout the cytosol, label motile puncta and decorate the nuclear envelope and plasma membrane. Functional studies through expression of dominant-negative myosin variants, RNAi (RNA interference) and T-DNA insertional analysis have shown that class XI myosins are required for organelle movement. Intriguingly, organelle movement is also linked to Arabidopsis growth and development. The present review tackles current findings relating to plant organelle movement and the role of myosins.

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Pernier, Julien, und Kristine Schauer. „Does the Actin Network Architecture Leverage Myosin-I Functions?“ Biology 11, Nr. 7 (29.06.2022): 989. http://dx.doi.org/10.3390/biology11070989.

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The actin cytoskeleton plays crucial roles in cell morphogenesis and functions. The main partners of cortical actin are molecular motors of the myosin superfamily. Although our understanding of myosin functions is heavily based on myosin-II and its ability to dimerize, the largest and most ancient class is represented by myosin-I. Class 1 myosins are monomeric, actin-based motors that regulate a wide spectrum of functions, and whose dysregulation mediates multiple human diseases. We highlight the current challenges in identifying the “pantograph” for myosin-I motors: we need to reveal how conformational changes of myosin-I motors lead to diverse cellular as well as multicellular phenotypes. We review several mechanisms for scaling, and focus on the (re-) emerging function of class 1 myosins to remodel the actin network architecture, a higher-order dynamic scaffold that has potential to leverage molecular myosin-I functions. Undoubtfully, understanding the molecular functions of myosin-I motors will reveal unexpected stories about its big partner, the dynamic actin cytoskeleton.

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Miller, D. D., S. P. Scordilis und P. K. Hepler. „Identification and localization of three classes of myosins in pollen tubes of Lilium longiflorum and Nicotiana alata“. Journal of Cell Science 108, Nr. 7 (01.07.1995): 2549–63. http://dx.doi.org/10.1242/jcs.108.7.2549.

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The presence and localization of actin and myosin have been examined in pollen tubes of Lilium longiflorum and Nicotiana alata. Immunoblot analysis of pollen tube extracts with antibodies to actin, myosins IA and IB, myosin II, and myosin V reveals the presence of these contractile proteins. Immunofluorescence microscopy using various methods to preserve the pollen tubes; chemical fixation, rapid freeze fixation and freeze substitution (RF-FS) followed by rehydration or by embeddment in a methacrylate mixture, was performed to optimize preservation. Immunocytochemistry reaffirmed that actin is localized longitudinally in the active streaming lanes and near the cortical surface of the pollen tube. Myosin I was localized to the plasma membrane, larger organelles, the surface of the generative cell and the vegetative nucleus, whereas, myosin V was found in the vegetative cytoplasm in a punctate fashion representing smaller organelles. Myosin II subfragment 1 and light meromyosin were localized in a punctate fashion on the larger organelles throughout the vegetative cytoplasm. In addition, isolated generative cells and vegetative nuclei labeled only with the myosin I antibody. Competition studies indicated the specificity of the heterologous antibodies utilized in this study suggesting the presence of three classes of myosins in pollen. These results lead to the following hypothesis: Myosin I may move the generative cell and vegetative nucleus unidirectionally through the pollen tube to the tip, while myosin V moves the smaller organelles and myosins I and II move the larger organelles (bidirectionally) that are involved in growth.

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Podlubnaya, Z. A., S. L. Malyshev, K. Nieznański und D. Stepkowski. „Order-disorder structural transitions in synthetic filaments of fast and slow skeletal muscle myosins under relaxing and activating conditions.“ Acta Biochimica Polonica 47, Nr. 4 (31.12.2000): 1007–17. http://dx.doi.org/10.18388/abp.2000_3954.

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In the previous study (Podlubnaya et al., 1999, J. Struc. Biol. 127, 1-15) Ca2+-induced reversible structural transitions in synthetic filaments of pure fast skeletal and cardiac muscle myosins were observed under rigor conditions (-Ca2+/+Ca2+). In the present work these studies have been extended to new more order-producing conditions (presence of ATP in the absence of Ca2+) aimed at arresting the relaxed structure in synthetic filaments of both fast and slow skeletal muscle myosin. Filaments were formed from column-purified myosins (rabbit fast skeletal muscle and rabbit slow skeletal semimebranosusproprius muscle). In the presence of 0.1 mM free Ca2+, 3 mM Mg2+ and 2 mM ATP (activating conditions) these filaments had a spread structure with a random arrangement of myosin heads and subfragments 2 protruding from the filament backbone. Such a structure is indistinguishable from the filament structures observed previously for fast skeletal, cardiac (see reference cited above) and smooth (Podlubnaya et al., 1999, J. Muscle Res. Cell Motil. 20, 547-554) muscle myosins in the presence of 0.1 mM free Ca2+. In the absence of Ca2+ and in the presence of ATP (relaxing conditions) the filaments of both studied myosins revealed a compact ordered structure. The fast skeletal muscle myosin filaments exhibited an axial periodicity of about 14.5 nm and which was much more pronounced than under rigor conditions in the absence of Ca2+ (see the first reference cited). The slow skeletal muscle myosin filaments differ slightly in their appearance from those of fast muscle as they exhibit mainly an axial repeat of about 43 nm while the 14.5 nm repeat is visible only in some regions. This may be a result of a slightly different structural properties of slow skeletal muscle myosin. We conclude that, like other filaments of vertebrate myosins, slow skeletal muscle myosin filaments also undergo the Ca2+-induced structural order-disorder transitions. It is very likely that all vertebrate muscle myosins possess such a property.

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