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  • alpha-actinin  (6)
  • mitosis  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Binding and distribution of fluorescently labeled filamin in permeabilized and living cells (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 345-359 
    Details
    ISSN: 0886-1544
    Keywords: alpha-actinin ; cytoskeleton ; muscle cells ; nonmuscle cells ; stress fiber ; myofibril ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study report the first development of a fluorescently labeled filamin. Smooth muscle was labeled with fluorscent dyes in order to study its interaction with stress fibers and myofibrils, both in living cells and in permeabilized cells. The labeled filamin bounds to the Z bands of isolated cross-striated myofibrils and to the Z bands and intercalated discs in both permeabilized embryonic cardiac myocytes and in frozen sections of adult rat venticle. In permeabilized embryonic chick myotubes, filamin bound to early myotubes but was absent at later stages. In living embryonic chick myotubes, the fluorescently labeled filamin was incorporated into the Z bands of myofibirls during early and late stages of develoment but was absent during an intermediate stages. In living cardiac myocytes, filamin-IAR was incorporated into nascent as well as fully formed sarcomeres throughout develoment. In permeabilized nonmuslce cells, labeled filamin bound to attachment plaques and foci of polygonal networks and to the dense bodies in stress fibers. The periodic bands of filamin in stress fibers had a longer spacing in fibroblasts than in epithelial cells. When injected into living cells, filamin was readily incorporated into stress fibers in a striated pattern. The fluorescent filamin bands were broader in injected cells, however, than they were in permeabilized cells. We have interpreted these results from living and permeabilized cells to mean that native filamin is distributed along the full lengh of the actin filaments in the stress fibers, with a higher concentration present in the dense bodies. A sarcomeric model is presented indicating the position of filamin with respect to other proteins in the stress fibers.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080407
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  • 2
    Electronic Resource
    Electronic Resource
    Alpha actinin distribution and extracellular matrix products during somitogenesis and neurulation in the chick embryo (1985)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 5 (1985), S. 491-506 
    Details
    ISSN: 0886-1544
    Keywords: Somitogenesis ; neurulation ; alpha-actinin ; morphogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A discrete stage in two different morphogenetic processes has been examined employing fluorescently labelled alpha-actinin as a probe to localize native alpha-actinin and antibodies to localize fibronectin and collagen type I. The stage of somitogenesis examined is the transition from the compact mesenchymal somitic mass to the epithelial somitic vesicle (ie, epithelialization of the somite). The stage of neurulation examined is the transition from the relatively flat neuroepithelium to the approximation of the neural folds. Before these morphogenetic movements begin, the neuroepithelium is sitting upon a basal lamina and interstitial collagen, and the somite is surrounded by a meshwork of interstitial collagen. During both of these processes, the cells become narrowed at their apices in the region of the tissue that is becoming concave, and alpha-actinin is localized in the apices. The localization of intracellular alpha-actinin and extracellular fibronectin, and the distribution of collagen, suggest that there is a coordinated appearance and distribution of these molecules that is temporally associated with these discrete morphogenetic events.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970050606
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  • 3
    Electronic Resource
    Electronic Resource
    Analysis of cell division using fluorescently labeled actin and myosin in living PtK2 cells (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 201-219 
    Details
    ISSN: 0886-1544
    Keywords: cytokinesis ; microinjection ; cleavage furrow ; mitosis ; midbody ; stress fibers ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Actin and the light chains of myosin were labeled with fluorescent dyes and injected into interphase PtK2 cells in order to study the changes in distribution of actin and myosin that occurred when the injected cells subsequently entered mitosis and divided. The first changes occurred when stress fibers in prophase cells began to disassemble. During this process, which began in the center of the cell, individual fibers shortened, and in a few fibers, adjacent bands of fluorescent myosin could be seen to move closer together. In most cells, stress fiber disassembly was complete by metaphase, resulting in a diffuse distribution of the fluorescent proteins throughout the cytoplasm with the greatest concentration present in the mitotic spindle. The first evidence of actin and myosin concentration in a cleavage ring occurred at late anaphase, just before furrowing could be detected. Initially, the intensity of fluorescence and the width of the fluorescent ring increased as the ring constricted. In cells with asymmetrically positioned mitotic spindles, both protein concentration and furrowing were first evident in the cortical regions closest to the equator of the mitotic spindle. As cytokinesis progressed in such asymmetrically dividing cells, fluorescent actin and myosin appeared at the opposite side of the cell just before furrowing activity could be seen there. At the end of cytokinesis, myosin and actin were concentrated beneath the membrane of the midbody and subsequently became organized in two rings at either end of the midbody.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140207
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  • 4
    Electronic Resource
    Electronic Resource
    Dynamics of organelles in the mitotic spindles of living cells: Membrane and microtubule interactions (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 19-39 
    Details
    ISSN: 0886-1544
    Keywords: endoplasmic reticulum ; carbocyanine dyes ; mitosis ; cell division ; membranous organelles ; confocal microscopy ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution and dynamics of the membranous organelles in two cell types were investigated during cell division. Live cells (either PtK2 or LLC-PK1) labeled with the vital dye 3,3′-dihexyloxacarbocyanine iodide [DiOC6(3)] were observed via serial optical sectioning with the laser-scanning confocal microscope. Z-series of labeled, dividing cells were collected every 1-2 minutes throughout mitosis, beginning at prophase and extending to the spreading of the daughter cells. Membrane distribution began to change from the onset of prophase in both cell types. When the mitotic spindle formed in prometaphase, fine tubular membranes, similar to those extending out to the edges of interphase cells aligned along the kinetochore spindle fibers. The lacy polygonal network typical of interphase cells persisted beneath the spindle, and a membrane network was also associated with the dorsal layer of the cell. As PtK2 cells reached metaphse, their spindles were nearly devoid of membrane staining, whereas the spindles of LLC-PK1 cells contained many tubular and small vesicular membranous structures. X-Z series of the LLC-PK1 metaphase spindle revealed a small cone of membranes that was separated from the rest of the cytoplasm by kinetochore MTs. In both cell types, as chromosome separation proceeded, the interzone remained nearly devoid of membranes until the onset of anaphase B. At this time the elongating interzonal microtubules were closely associated with the polygonal network of endoplasmic reticulum. Cytokinesis caused a compression, and then an exclusion of organelles from the midbody. Immunofluorescence staining with anti-tubulin antibodies suggested that spindle membranes were associated with microtubules throughout mitosis. In addition, taxol induced a dense and extensive collection of small vesicles to collect at the spindle poles of both cell types. Nocodazole treatment induced a distinct loss of organization of the membranous components of the spindles. Together these results suggest that microtubules organize the membrane distribution in mitotic cells, and that this organization may vary in different cell types depending on the quantity of microtubules within the spindle. © 1993 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260104
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  • 5
    Electronic Resource
    Electronic Resource
    Dynamics of actin and alpha-actinin in the tails of Listeria monocytogenes in Infected PtK2 Cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 346-358 
    Details
    ISSN: 0886-1544
    Keywords: Listeria monocytogenes ; actin ; alpha-actinin ; actin polymerization ; assembly ; disassembly ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Listeria monocytogenes can penetrate and multiply within a variety of cell types, including the PtK2 kidney epithelial line. Once released within the cytoplasm, L. monocytogenes acquires the capacity for rapid movement through the host cell [Dabiri et al., 1990: Proc. Natl. Acad. Sci. 87:6068-6072]. In the process, actin monomers are inserted in proximity to one end of the bacterium, forming a column or tail of actin filaments [Sanger et al., 1992: Infect. Immun. 60:3609-3619]. The rate of new actin filament growth correlates closely with the speed of bacterial migration. In this study we have used fluorescently labeled actin and alpha-actinin to monitor the movement and turnover rate of actin and alpha-actinin molecules in the tails. The half-lives of the actin and alpha-actinin present in the tails are approximately the same: actin, 58.7 sec; alpha-actinin, 55.3 sec. The half-life of alpha-actinin surrounding a dividing bacterium was 30 sec, whereas its half-life in the tails that formed behind the two daughter cells was about 20-30% longer. We discovered that the speeds of the bacteria are not constant, but show aperiodic episodes of decreased and increased speeds. There is a fluctuation also in the intensities of the fluorescent probes at the bacterium/tail interface, implying that there is a fluctuation in the number of actin filaments forming there. There was no strong correlation, however, between these fluctuating intensities and changes in speed of the bacteria. These measurements suggest that while actin polymerization at the bacterial surface is coupled to the movement of the bacterium, the periodic changes in intracellular motility are not a simple function of the number of actin filaments nucleating at the bacterial surfaces. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280408
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  • 6
    Electronic Resource
    Electronic Resource
    Formation of myofibrils in spreading chick cardiac myocytes (1984)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 405-416 
    Details
    ISSN: 0886-1544
    Keywords: cardiac muscle ; myofibril ; cell spreading ; Z bands ; alpha-actinin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cardiac myocytes were isolated from 5-6-day-old chick embryos and allowed to spread in culture. The distribution of alpha-actinin in the cells was followed for five days in culture by exposing permeabilized cells to rhodamine-labeled alpha-actinin and also by injecting the labeled alpha-actinin into living myocytes. In addition to labeling the Z bands of sarcomeres, the added alpha-actinin also labeled small particles that were usually arranged periodically in linear arrays with a spacing between particles of 0.3-2.0 μm. Actin was localized between the particles of alpha-actinin by means of fluorescein-labeled heavy meromyosin. The punctate localization of alpha-actinin was prominent in pseudopods, behind ruffles, and at the periphery of spreading cells. Long rows of particles of alpha-actinin were often parallel to one another with the alpha-actinin particles in register. These linear arrays appeared to merge laterally to form strands with broader concentrations of alpha-actinin. Other linear arrays were parallel to myofibrils in the cell and some extended outward from the ends of myofibrils. We conclude that during spreading of cardiac myocytes, myofibrils form at the cell periphery behind the extending margins of the cell, and that the aggregates of alpha-actinin found in these areas are nascent Z bands in the forming myofibrils.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970040602
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  • 7
    Electronic Resource
    Electronic Resource
    Stress fiber and cleavage furrow formation in living cells microinjected with fluorescently labeled α-actinin (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 7 (1987), S. 209-220 
    Details
    ISSN: 0886-1544
    Keywords: cytokinesis ; mitosis ; PtK2 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: α-Actinins, isolated from muscle and nonmuscle sources and labeled with various fluorescent dyes, were microinjected into living PtK2 cells during interphase to observe the reformation of stress fibers following cell division. Fluorescently labeled ovalbumin and bovine serum albumin were also injected as control proteins. α-Actinin was incorporated into stress fibers within 5 minutes after injection and remained present in the fibers for up to 11 days. The pattern of incorporation was the same regardless of whether the α-actinin was isolated from muscle or nonmuscle tissues or whether it was labeled with fluorescein, Lucifer Yellow, or rhodamine dyes. In contrast, neither labeled ovalbumin nor bovine serum albumin were incorporated into stress fibers. When the injected cells entered prophase, all stress fibers disassembled, resulting in a distribution of the fluorescent α-actinin throughout the cytoplasm. During cytokinesis, the fluorescent α-actinin was concentrated in the broad area between the separated chromosomes and along the edge of the cell in the cleavage area. Within 10 minutes after the completion of cleavage, the first fluorescent stress fibers reformed parallel to the spreading edges of the daughter cells and in close association with the midbody with a concomitant loss of α-actinin in the former cleavage furrow. Additional fibers formed adjacent to these first stress fibers. In some cases, new stress fibers formed between two existing stress fibers and some stress fibers moved up to 4 μm apart from one another in the course of 2 hours. Thus, fluorescent α-actinin, injected into living cells, undergoes the same cyclical changes in distribution as endogenous α-actinin during the cell cycle: from stress fibers to cleavage furrow and back to stress fibers.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970070304
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  • 8
    Electronic Resource
    Electronic Resource
    Intact alpha-actinin molecules are needed for both the assembly of actin into the tails and the locomotion of Listeria monocytogenes inside infected cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 97-107 
    Details
    ISSN: 0886-1544
    Keywords: Listeria ; actin ; alpha-actinin ; vinculin ; talin ; filopodia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: After the infectious bacterium, Listeria monocytogenes, is phagocytosed by a host cell, it leaves the lysosome and recruits the host cell's cytoskeletal proteins to assemble a stationary tail composed primarily of actin filaments cross-linked with alpha-actinin. The continual recruitment of contractile proteins to the interface between the bacterium and the tail accompanies the propulsion of the bacterium ahead of the elongating tail. When a bacterium contacts the host cell membrane, it pushes out the membrane into an undulating tubular structure or filopodium that envelops the bacterium at the tip with the tail of cytoskeletal proteins behind it. Previous work has demonstrated that alpha-actinin can be cleaved into two proteolytic fragments whose microinjection into cells interferes with stress fiber integrity. Microinjection of the 53 kD alpha-actinin fragment into cells infected with Listeria monocytogenes, induces the loss of tails from bacteria and causes the bacteria to become stationary. Infected cells that possess filopodia when injected with the 53 kD fragment lose their filopodia. These results indicate that intact alpha-actinin molecules play an important role in the intracellular motility of Listeria, presumably by stabilizing the actin fibers in the stationary tails that are required for the bacteria to move forward. Fluorescently labeled vinculin associated with the tails when it was injected into infected cells. Talin antibody staining indicated that this protein, also, is present in the tails. These observations suggest that the tails share properties of attachment plaques normally present in the host cells. This model would explain the ability of the bacterium (1) to move within the cytoplasm and (2) to push out the surface of the cell to form a filopodium. The attachment plaque proteins, alpha-actinin, talin, and vinculin, may bind and stabilize the actin filaments as they polymerize behind the bacteria and additionally could also enable the tails to bind to the cell membrane in the filopodia. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280202
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  • 9
    Electronic Resource
    Electronic Resource
    Contractile protein dynamics of myofibrils in paired adult rat cardiomyocytes (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 301-312 
    Details
    ISSN: 0886-1544
    Keywords: intercated discs ; microinjection ; actin ; alpha-actinin ; vinculin ; myosin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The purpose of this study was to determine how quickly contractile proteins are incorporated into the myofibrils of freshly isolated cardiomyocytes and to determine whether there are regions of the cells that are more dynamic than others in their ability to incorporate the proteins. Paired cardiomyocytes joined at intercalated discs and single cells were isolated from adult rats, and microinjected 3 hours later with fluorescently labeied actin, alpha-actinin, myosin light chains, and vinculin. The cells were fixed and permeabilized at various period, 5 seconds and longer, after microinjection. Actin became incorporated throughout the I-Bands in as short a time as 5 seconds. The free edges of the cells, which were formerly intercalated discs, exhibited concentrations of actin greater than that incorporated in the I-Bands. This extra concentration of actin was not detected, however, at intact intercalated discs connecting paired cells. Alpha-actinin was incorporated immediately into Z-Bands and intercalated discs. Vinculin, also, was localized at the Z-Bands and at intercalated discs, but in contrast to alpha-actinin, there was a higher concentration of vinculin in the region of the intact intercalated discs. Both alpha-actinin and vinculin were concentrated at the free ends of the cells that were formerly parts of intercalated discs. Myosin light chains were observed to incorporate into the A-Bands in periods as short as 5 seconds. These results suggest that the myofibrils of adult cardiomyocytes may be capable of rapid isoform transitions along the length of the myofibrils. The rapid accumulation of fluorescent actin, alpha-actinin, and vinculin in membrane sites that were previously parts of intercalated discs, may reflect the response to locomotory activity that is initiated in these areas as cells spread in culture. A similar response after an injury in the intact heart could allow repair to occur. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260405
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