scholarly journals Anillin, a contractile ring protein that cycles from the nucleus to the cell cortex.

1995 ◽  
Vol 131 (1) ◽  
pp. 165-178 ◽  
Author(s):  
C M Field ◽  
B M Alberts
Keyword(s):  
Cell Cycle ◽  
Actin Filaments ◽  
Myosin Ii ◽  
Drosophila Embryo ◽  
Cell Cortex ◽  
Cleavage Furrow ◽  
Protein Fragments ◽  
Culture Cells ◽  
Acid Protein ◽  
Sds Page

We report the cDNA sequence and localization of a protein first identified by actin filament chromatography of Drosophila embryo extracts as ABP8 (Miller, K. G., C. M. Field, and B. M. Alberts. 1989. J. Cell Biol. 109:2963-2975). The cDNA encodes a 1201-amino acid protein which we name anillin. Anillin migrates at 190 kD on SDS-PAGE. Anillin is expressed throughout Drosophila development and in tissue culture cells. By immunofluorescence, anillin localizes to the nucleus of interphase cells, except in the syncytial embryo where it is always cytoplasmic. During metaphase, it is present in the cytoplasm and cortex, and during anaphase-telophase it becomes highly enriched in the cleavage furrow along with myosin II. In the syncytial embryo, anillin, along with myosin-II, is enriched in cortical areas undergoing cell cycle regulated invagination including metaphase furrows and the cellularization front. In contractile rings, metaphase furrows, and nascent ring canals, anillin remains bound to the invaginated cortex suggesting a stabilizing role. Anillin is not expressed in cells that have left the cell cycle. Anillin isolated from embryo extracts binds directly to actin filaments. The domain responsible for this binding has been mapped to a region of 244 amino acids by expression of protein fragments in bacteria. This domain, which is monomeric in solution, also bundles actin filaments. We speculate that anillin plays a role in organizing and/or stabilizing the cleavage furrow and other cell cycle regulated, contractile domains of the actin cytoskeleton.

scholarly journals Molecular Mechanism of Cytokinesis

2019 ◽  
Vol 88 (1) ◽  
pp. 661-689 ◽  
Author(s):  
Thomas D. Pollard ◽  
Ben O'Shaughnessy
Keyword(s):  
Cell Cycle ◽  
Computer Simulations ◽  
Actin Filaments ◽  
Myosin Ii ◽  
Cleavage Furrow ◽  
Animal Cells ◽  
Contractile Ring ◽  
Daughter Cells ◽  
Ancient Proteins ◽  
Biochemical Mechanisms

Division of amoebas, fungi, and animal cells into two daughter cells at the end of the cell cycle depends on a common set of ancient proteins, principally actin filaments and myosin-II motors. Anillin, formins, IQGAPs, and many other proteins regulate the assembly of the actin filaments into a contractile ring positioned between the daughter nuclei by different mechanisms in fungi and animal cells. Interactions of myosin-II with actin filaments produce force to assemble and then constrict the contractile ring to form a cleavage furrow. Contractile rings disassemble as they constrict. In some cases, knowledge about the numbers of participating proteins and their biochemical mechanisms has made it possible to formulate molecularly explicit mathematical models that reproduce the observed physical events during cytokinesis by computer simulations.

scholarly journals Polar relaxation by dynein-mediated removal of cortical myosin II

2020 ◽  
Vol 219 (8) ◽  
Author(s):  
Bernardo Chapa-y-Lazo ◽  
Motonari Hamanaka ◽  
Alexander Wray ◽  
Mohan K. Balasubramanian ◽  
Masanori Mishima
Keyword(s):  
Recent Work ◽  
Molecular Mechanism ◽  
Molecular Mechanisms ◽  
Myosin Ii ◽  
Cell Cortex ◽  
Cleavage Furrow ◽  
Contractile Ring ◽  
C Elegans ◽  
Polar Cell

Nearly six decades ago, Lewis Wolpert proposed the relaxation of the polar cell cortex by the radial arrays of astral microtubules as a mechanism for cleavage furrow induction. While this mechanism has remained controversial, recent work has provided evidence for polar relaxation by astral microtubules, although its molecular mechanisms remain elusive. Here, using C. elegans embryos, we show that polar relaxation is achieved through dynein-mediated removal of myosin II from the polar cortexes. Mutants that position centrosomes closer to the polar cortex accelerated furrow induction, whereas suppression of dynein activity delayed furrowing. We show that dynein-mediated removal of myosin II from the polar cortexes triggers a bidirectional cortical flow toward the cell equator, which induces the assembly of the actomyosin contractile ring. These results provide a molecular mechanism for the aster-dependent polar relaxation, which works in parallel with equatorial stimulation to promote robust cytokinesis.

scholarly journals Dynacortin, a Genetic Link between Equatorial Contractility and Global Shape Control Discovered by Library Complementation of a Dictyostelium discoideum Cytokinesis Mutant

2000 ◽  
Vol 150 (4) ◽  
pp. 823-838 ◽  
Author(s):  
Douglas N. Robinson ◽  
James A. Spudich
Keyword(s):  
Dictyostelium Discoideum ◽  
Shape Control ◽  
Myosin Ii ◽  
Genetic Interactions ◽  
Cell Cortex ◽  
Cleavage Furrow ◽  
Family Protein ◽  
Globally Distributed ◽  
Suppression Strategy ◽  
Novel Protein

We have developed a system for performing interaction genetics in Dictyostelium discoideum that uses a cDNA library complementation/multicopy suppression strategy. Chemically mutagenized cells were screened for cytokinesis-deficient mutants and one mutant was subjected to library complementation. Isolates of four different genes were recovered as modifiers of this strain's cytokinesis defect. These include the cleavage furrow protein cortexillin I, a novel protein we named dynacortin, an ezrin-radixin-moesin-family protein, and coronin. The cortexillin I locus and transcript were found to be disrupted in the strain, identifying it as the affected gene. Dynacortin is localized partly to the cell cortex and becomes enriched in protrusive regions, a localization pattern that is similar to coronin and partly dependent on RacE. During cytokinesis, dynacortin is found in the cortex and is somewhat enriched at the poles. Furthermore, it appears to be reduced in the cleavage furrow. The genetic interactions and the cellular distributions of the proteins suggest a hypothesis for cytokinesis in which the contraction of the medial ring is a function of spatially restricted cortexillin I and myosin II and globally distributed dynacortin, coronin, and RacE.

scholarly journals Protocadherin 7 localizes to the plasma membrane during mitosis and promotes cytokinesis by a palmitoylation-dependent mechanism

2020 ◽  
Author(s):  
Nazlı Ezgi Özkan-Küçük ◽  
Mohammad Haroon Qureshi ◽  
Berfu Nur Yiğit ◽  
Altuğ Kamacıoğlu ◽  
Nima Bavili ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Membrane Trafficking ◽  
Myosin Ii ◽  
Cell Types ◽  
Mitotic Cell ◽  
Cortical Reorganization ◽  
Cell Cortex ◽  
Cleavage Furrow ◽  
Cytoskeleton Organization ◽  
Dependent Mechanism

ABSTRACTSuccessful cell division requires dramatic reorganization of the cell cortex in coordination with actomyosin cytoskeleton organization, membrane trafficking and cell adhesion. Although the contractile actomyosin ring is considered as hallmark of cytokinesis, in some cell types cell adhesion systems have been shown to drive cytokinesis independently from actomyosin function. We previously reported that Protocadherin 7 (PCDH7) localizes to the mitotic cortex which is required for building up the full mitotic rounding pressure. Here, we show that PCDH7 localizes to the mitotic cell cortex and to the cleavage furrow by a palmitoylation-dependent mechanism. At the cleavage furrow, PCDH7 facilitates the activation of myosin II and successful cytokinesis. Strikingly, PCDH7 promotes cytokinesis even when the myosin II contractility and integrin mediated adhesion are blocked. This work describes a palmitoylation-dependent cortical reorganization which promotes cytokinesis under different conditions.

Genetic and morphological evidence for two parallel pathways of cell-cycle-coupled cytokinesis inDictyostelium

2002 ◽  
Vol 115 (10) ◽  
pp. 2241-2251 ◽  
Author(s):  
Akira Nagasaki ◽  
Eugenio L. de Hostos ◽  
Taro Q. P. Uyeda
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Morphological Changes ◽  
Mutant Cell ◽  
Myosin Ii ◽  
Morphological Evidence ◽  
Cleavage Furrow ◽  
Cycle Progression ◽  
Parallel Pathways ◽  
Substrate Adhesion

Myosin-II-null cells of Dictyostelium discoideum cannot divide in suspension, consistent with the dogma that myosin II drives constriction of the cleavage furrow and, consequently, cytokinesis (cytokinesis A). Nonetheless, when grown on substrates, these cells exhibit efficient,cell-cycle-coupled division, suggesting that they possess a novel,myosin-II-independent, adhesion-dependent method of cytokinesis (cytokinesis B). Here we show that double mutants lacking myosin II and either AmiA or coronin, both of which are implicated in cytokinesis B, are incapable of cell-cycle-coupled cytokinesis. These double mutants multiplied mainly by cytokinesis C, a third, inefficient, method of cell division, which requires substrate adhesion and is independent of cell cycle progression. In contrast,double mutants lacking AmiA and coronin were no sicker than each of the single mutants, indicating that the severe defects of myosin II-/AmiA- or myosin II-/coronin-mutants are not simple additive effects of two mutations. We take this as genetic evidence for two parallel pathways both of which lead to cell-cycle-coupled cytokinesis. This conclusion is supported by differences in morphological changes during cytokinesis in the mutant cell lines.

scholarly journals Concentration of an integral membrane protein, CD43 (leukosialin, sialophorin), in the cleavage furrow through the interaction of its cytoplasmic domain with actin-based cytoskeletons.

1993 ◽  
Vol 120 (2) ◽  
pp. 437-449 ◽  
Author(s):  
S Yonemura ◽  
A Nagafuchi ◽  
N Sato ◽  
S Tsukita
Keyword(s):  
Cell Cycle ◽  
Membrane Protein ◽  
Actin Filaments ◽  
Integral Membrane Protein ◽  
Cytoplasmic Domain ◽  
Electron Microscopic Level ◽  
Cleavage Furrow ◽  
Electron Microscopic ◽  
Attachment Sites ◽  
E Cadherin

In leukocytes such as thymocytes and basophilic leukemia cells, a glycosilated integral membrane protein called CD43 (leukosialin or sialophorin), which is defective in patients with Wiskott-Aldrich syndrome, was highly concentrated in the cleavage furrow during cytokinesis. Not only at the mitotic phase but also at interphase, CD43 was precisely colocalized with ezrin-radixin-moesin family members. (ERM), which were previously reported to play an important role in the plasma membrane-actin filament association in general. At the electron microscopic level, throughout the cell cycle, both CD43 and ERM were tightly associated with microvilli, providing membrane attachment sites for actin filaments. We constructed a cDNA encoding a chimeric molecule consisting of the extracellular domain of mouse E-cadherin and the transmembrane/cytoplasmic domain of rat CD43, and introduced it into mouse L fibroblasts lacking both endogenous CD43 and E-cadherin. In dividing transfectants, the chimeric molecules were concentrated in the cleavage furrow together with ERM, and both proteins were precisely colocalized throughout the cell cycle. Furthermore, using this transfection system, we narrowed down the domain responsible for the CD43-concentration in the cleavage furrow. Based on these findings, we conclude that CD43 is concentrated in the cleavage furrow through the direct or indirect interaction of its cytoplasmic domain with ERM and actin filaments.

Microtubule-mediated centrosome motility and the positioning of cleavage furrows in multinucleate myosin II-null cells

1998 ◽  
Vol 111 (9) ◽  
pp. 1227-1240 ◽  
Author(s):  
R. Neujahr ◽  
R. Albrecht ◽  
J. Kohler ◽  
M. Matzner ◽  
J.M. Schwartz ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Myosin Ii ◽  
Cytoplasmic Dynein ◽  
Cell Cortex ◽  
Cleavage Furrow ◽  
Contractile Ring ◽  
Mitotic Apparatus ◽  
Alpha Tubulin ◽  
Multinucleate Cells ◽  
Green Fluorescent

To study centrosome motility and the interaction of microtubules with the cell cortex in mitotic, post-mitotic and interphase cells, (alpha)-tubulin was tagged in Dictyostelium discoideum with green fluorescent protein. Multinucleate cells formed by myosin II-null mutants proved to be especially suited for the analysis of the control of cleavage furrow formation by the microtubule system. After docking of the mitotic apparatus onto the cell cortex during anaphase, the cell surface is activated to form ruffles on top of the asters of microtubules that emanate from the centrosomes. Cleavage furrows are initiated at spaces between the asters independently of the positions of spindles. Once initiated, the furrows expand as deep folds without a continued connection to the microtubule system. Occurrence of unilateral furrows indicates that a closed contractile ring is dispensable for cytokinesis in Dictyostelium. The progression of cytokinesis in the multinucleate cells underlines the importance of proteins other than myosin II in specifying a cleavage furrow. The analysis of centrosome motility suggests a major role for a minus-end directed motor protein, probably cytoplasmic dynein, in applying traction forces on guiding microtubules that connect the centrosome with the cell cortex.

scholarly journals Spindle–F-actin interactions in mitotic spindles in an intact vertebrate epithelium

2019 ◽  
Vol 30 (14) ◽  
pp. 1645-1654 ◽  
Author(s):  
Angela M. Kita ◽  
Zachary T. Swider ◽  
Ivan Erofeev ◽  
Mary C. Halloran ◽  
Andrew B. Goryachev ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Epithelial Cells ◽  
Actin Filaments ◽  
Cell Cortex ◽  
Actin Network ◽  
Mitotic Spindles ◽  
Spindle Poles ◽  
Internal Network ◽  
Transient Contact ◽  
Improved Methods

Mitotic spindles are well known to be assembled from and dependent on microtubules. In contrast, whether actin filaments (F-actin) are required for or are even present in mitotic spindles has long been controversial. Here we have developed improved methods for simultaneously preserving F-actin and microtubules in fixed samples and exploited them to demonstrate that F-actin is indeed associated with mitotic spindles in intact Xenopus laevis embryonic epithelia. We also find that there is an “F-actin cycle,” in which the distribution and organization of spindle F-actin changes over the course of the cell cycle. Live imaging using a probe for F-actin reveals that at least two pools of F-actin are associated with mitotic spindles: a relatively stable internal network of cables that moves in concert with and appears to be linked to spindles, and F-actin “fingers” that rapidly extend from the cell cortex toward the spindle and make transient contact with the spindle poles. We conclude that there is a robust endoplasmic F-actin network in normal vertebrate epithelial cells and that this network is also a component of mitotic spindles. More broadly, we conclude that there is far more internal F-actin in epithelial cells than is commonly believed.

scholarly journals Cleavage furrow: timing of emergence of contractile ring actin filaments and establishment of the contractile ring by filament bundling in sea urchin eggs

1994 ◽  
Vol 107 (7) ◽  
pp. 1853-1862 ◽  
Author(s):  
I. Mabuchi
Keyword(s):  
Sea Urchin ◽  
Binding Sites ◽  
Actin Filaments ◽  
Early Stage ◽  
Cortical Layer ◽  
Cell Cortex ◽  
Cleavage Furrow ◽  
Cortical Actin ◽  
Contractile Ring ◽  
Rhodamine Phalloidin

Cleavage furrow formation at the first cell division of sea urchin and sand dollar eggs was investigated in detail by fluorescence staining of actin filaments with rhodamine-phalloidin of either whole eggs or isolated egg cortices. Cortical actin filaments were clustered at anaphase and then the clusters became fibrillar at the end of anaphase. The timing when the contractile ring actin filaments appear was precisely determined in the course of mitosis: accumulation of the contractile ring actin filaments at the equatorial cell cortex is first noticed at the beginning of telophase (shortly before furrow formation), when the chromosomal vesicles are fusing with each other. The accumulated actin filaments were not well organized at the early stage but were organized into parallel bundles as the furrowing progressed. The bundles were finally fused into a tightly packed filament belt. Wheat germ agglutinin (WGA)-binding sites were distributed on the surface of the egg in a manner similar to the actin filaments after anaphase. The WGA-binding sites became accumulated in the contractile ring together with the contractile ring actin filaments, indicating an intimate relationship between these sites and actin filament-anchoring sites on the plasma membrane. Myosin also appeared in the contractile ring together with the actin filaments. The ‘cleavage stimulus’, a signal hypothesized by Rappaport (reviewed by R. Rappaport (1986) Int. Rev. Cytol. 105, 245–281) was suggested to induce aggregation or bundling of the actin filaments in the cortical layer.

scholarly journals Polar relaxation by dynein-mediated removal of cortical myosin II

2019 ◽  
Author(s):  
Bernardo Chapa-y-Lazo ◽  
Motonari Hamanaka ◽  
Alexander Wray ◽  
Mohan K. Balasubramanian ◽  
Masanori Mishima
Keyword(s):  
Recent Work ◽  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Myosin Ii ◽  
Cell Cortex ◽  
Cleavage Furrow ◽  
Contractile Ring ◽  
C Elegans ◽  
Polar Cell ◽  
First Time

AbstractNearly 6 decades ago, Lewis Wolpert proposed the relaxation of the polar cell cortex by the radial arrays of astral microtubules as a mechanism for cleavage furrow induction (White and Borisy, 1983; Wolpert, 1960). While this mechanism has remained controversial (Rappaport, 1996), recent work has provided evidence for polar relaxation by astral microtubules (Chen et al., 2008; Dechant and Glotzer, 2003; Foe and Dassow, 2008; Murthy and Wadsworth, 2008; Werner et al., 2007), although its molecular mechanisms remain elusive. Here, using C. elegans embryos, we show that polar relaxation is achieved through dynein-mediated removal of myosin II from the polar cortexes. Mutants that position centrosomes closer to the polar cortex accelerated furrow induction whereas suppression of dynein activity delayed furrowing. We provide evidence that dynein-mediated removal of myosin II from the polar cortexes triggers cortical flow towards the cell equator, which induces the assembly of the actomyosin contractile ring. These studies for the first time provide a molecular basis for the aster-dependent polar relaxation, which works in parallel with equatorial stimulation to promote robust cytokinesis.

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