Myosin II-independent processes in mitotic cells of Dictyostelium discoideum: redistribution of the nuclei, re-arrangement of the actin system and formation of the cleavage furrow

1997 ◽  
Vol 110 (2) ◽  
pp. 123-137 ◽  
Author(s):  
R. Neujahr ◽  
C. Heizer ◽  
G. Gerisch
Keyword(s):  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Solid Surface ◽  
Myosin Ii ◽  
Cell Cortex ◽  
Cleavage Furrow ◽  
Multinucleated Cells ◽  
Dynamic Cell ◽  
Separated Sets ◽  
Mutant Cells

Mitosis was studied in multinucleated and mononucleated mutant cells of Dictyostelium discoideum that lack myosin II (Manstein et al. (1989) EMBO J. 8, 923–932). Multinucleated cells were produced by culture in suspension, mononucleated cells were enriched by growth on a solid surface (DeLozanne and Spudich (1987) Science 236, 1086–1091). The multinucleated cells disclosed interactions of mitotic complexes with the cell cortex that were not apparent in normal, mononucleated cells. During the anaphase stage, entire mitotic complexes consisting of spindle, microtubule asters, and separated sets of chromosomes were translocated to the periphery of the cells. These complexes were appended at a distance of about 3 microns from the cell surface, in a way that the spindle became orientated in parallel to the surface. Subsequently, lobes of the cell surface were formed around the asters of microtubules. These lobes were covered with tapered protrusions rich in coronin, an actin associated protein that typically accumulates in dynamic cell-surface projections (DeHostos et al. (1991) EMBO J. 10, 4097–4104). During their growth on a solid surface, mononucleated myosin II-null cells passed through the mitotic cleavage stages with a speed comparable to wild-type cells. Cytokinesis as linked to mitosis is distinguishable by several parameters from traction mediated cytofission, which results in the pinching off of pieces of a multinucleated cell in the interphase. The possibility is discussed that cells can cleave during mitosis without forming a contractile ring at the site of the cleavage furrow.

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 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 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.

Differentiation of Dictyostelium discoideum mutant cells in a shaken suspension culture and the effect of cyclic AMP

1981 ◽  
Vol 51 (1) ◽  
pp. 131-142
Author(s):  
K. Abe ◽  
Y. Saga ◽  
H. Okada ◽  
K. Yanagisawa
Keyword(s):  
Cyclic Amp ◽  
Suspension Culture ◽  
Dictyostelium Discoideum ◽  
Solid Surface ◽  
Enzyme Activities ◽  
Parental Strain ◽  
Mutant Cell ◽  
Specific Activities ◽  
Mutant Cells ◽  
Kinetics Of

In Dictyostelium discoideum, 16 mutants in which cells differentiate into spores and stalk cells without normal morphogenesis were isolated. All these mutants are rapidly developing and capable of differentiating in a shaken suspension of phosphate buffer.The developmental kinetics of specific activities of enzymes in one of the mutants, HTY 1851, cultured in the suspension was compared with that in the parental strain, X2, developed on a solid surface. Most of the enzyme activities appeared much earlier and the peaks of the activities were lower in HTY1851 than X2, but the order or appearance of the activities was the same in both the strains cultured under the conditions described above. These results suggest that the biochemical steps in the development of the mutant in a shaken suspension are essentially the same as those of the parental strain X2 on a solid surface. It was also found that addition of cyclic AMP (2.5 X 10-5 M to 1 X 10-4 M) to the mutant cell suspension 6–8 h after the initiation of development induced an increase in the number of spores and the specific activities of some enzymes to values twice as high as those of an untreated control.

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.

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 An Essential Role for a Membrane Lipid in Cytokinesis

2000 ◽  
Vol 149 (6) ◽  
pp. 1215-1224 ◽  
Author(s):  
Kazuo Emoto ◽  
Masato Umeda
Keyword(s):  
Cell Surface ◽  
Mammalian Cells ◽  
Mutant Cell ◽  
Myosin Ii ◽  
Membrane Lipid ◽  
Cleavage Furrow ◽  
Contractile Ring ◽  
Cytoplasmic Bridge ◽  
Daughter Cells

Phosphatidylethanolamine (PE) is a major membrane phospholipid that is mainly localized in the inner leaflet of the plasma membrane. We previously demonstrated that PE was exposed on the cell surface of the cleavage furrow during cytokinesis. Immobilization of cell surface PE by a PE-binding peptide inhibited disassembly of the contractile ring components, including myosin II and radixin, resulting in formation of a long cytoplasmic bridge between the daughter cells. This blockade of contractile ring disassembly was reversed by removal of the surface-bound peptide, suggesting that the PE exposure plays a crucial role in cytokinesis. To further examine the role of PE in cytokinesis, we established a mutant cell line with a specific decrease in the cellular PE level. On the culture condition in which the cell surface PE level was significantly reduced, the mutant ceased cell growth in cytokinesis, and the contractile ring remained in the cleavage furrow. Addition of PE or ethanolamine, a precursor of PE synthesis, restored the cell surface PE on the cleavage furrow and normal cytokinesis. These findings provide the first evidence that PE is required for completion of cytokinesis in mammalian cells, and suggest that redistribution of PE on the cleavage furrow may contribute to regulation of contractile ring disassembly.

scholarly journals Talin-Null Cells of Dictyostelium Are Strongly Defective in Adhesion to Particle and Substrate Surfaces and Slightly Impaired in Cytokinesis

1997 ◽  
Vol 138 (2) ◽  
pp. 349-361 ◽  
Author(s):  
Jens Niewöhner ◽  
Igor Weber ◽  
Markus Maniak ◽  
Annette Müller-Taubenberger ◽  
Günther Gerisch
Keyword(s):  
Cell Surface ◽  
Gene Replacement ◽  
Cell Cortex ◽  
Mitotic Apparatus ◽  
Small Areas ◽  
Substrate Adhesion ◽  
Substrate Surfaces ◽  
Cell To Cell Adhesion ◽  
Neuronal Growth Cones ◽  
Mutant Cells

Dictyostelium discoideum contains a full-length homologue of talin, a protein implicated in linkage of the actin system to sites of cell-to-substrate adhesion in fibroblasts and neuronal growth cones. Gene replacement eliminated the talin homologue in Dictyostelium and led to defects in phagocytosis and cell-to-substrate interaction of moving cells, two processes dependent on a continuous cross talk between the cell surface and underlying cytoskeleton. The uptake rate of yeast particles was reduced, and only bacteria devoid of the carbohydrate moiety of cell surface lipopolysaccharides were adhesive enough to be recruited by talin-null cells in suspension and phagocytosed. Cell-to-cell adhesion of undeveloped cells was strongly impaired in the absence of talin, in contrast with the cohesion of aggregating cells mediated by the phospholipid-anchored contact site A glycoprotein, which proved to be less talin dependent. The mutant cells were still capable of moving and responding to a chemoattractant, although they attached only loosely to a substrate via small areas of their surface. With their high proportion of binucleated cells, the talin-null mutants revealed interactions of the mitotic apparatus with the cell cortex that were not obvious in mononucleated cells.

scholarly journals Robust maintenance of cell surface tension in mitosis by RhoA-driven myosin II mechanoresponse

2021 ◽  
Author(s):  
Jingjing Ding ◽  
Chao Wang ◽  
Qiaodong Wei ◽  
Shoukang Du ◽  
Xiaobo Gong ◽  
...  
Keyword(s):  
Surface Tension ◽  
Cell Surface ◽  
Myosin Ii ◽  
Rho Kinase ◽  
Cell Cortex ◽  
Tail Domain ◽  
Rhoa Activation ◽  
Head Domain ◽  
Confined Environment ◽  
Muscle Myosin

AbstractAs cells enter mitosis, cell cortex contraction generates surface tension to establish a geometry feasible for division in a physically confined environment. Cell surface tension rises in prophase and continues to stay constant during metaphase to support mitosis. How the cell surface tension is maintained throughout mitosis is not well explored. We show that the cell surface tension is actively maintained by a mechanosensitive RhoA pathway at the cell cortex during mitosis. Mechanical activation of RhoA leads to non-muscle myosin IIB (NMIIB) stabilization and mechanosensitive accumulation at the cell cortex via Rho kinase (ROCK) regulation of the NMIIB head domain. Interestingly, when the NMIIB tail domain regulation is perturbed, the NMIIB has reduced ability to generate tension but could still support mitotic cells to withstand compressive stress by undergoing mechanosensitive accumulation at the cell cortex. Thus, mechanical RhoA activation drives NMIIB mechanoresponse via its head domain regulation to maintain cell surface tension during mitosis.

scholarly journals Unconventional Secretion of AcbA in Dictyostelium discoideum through a Vesicular Intermediate

2010 ◽  
Vol 9 (7) ◽  
pp. 1009-1017 ◽  
Author(s):  
Matthew Cabral ◽  
Christophe Anjard ◽  
Vivek Malhotra ◽  
William F. Loomis ◽  
Adam Kuspa
Keyword(s):  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Wild Type ◽  
Content Type ◽  
Sensitive Factor ◽  
Late Step ◽  
Unconventional Secretion ◽  
Membrane Bound ◽  
Acyl Coenzyme A ◽  
Mutant Cells

ABSTRACT The acyl coenzyme A (CoA) binding protein AcbA is secreted unconventionally and processed into spore differentiation factor 2 (SDF-2), a peptide that coordinates sporulation in Dictyostelium discoideum. We report that AcbA is localized in vesicles that accumulate in the cortex of prespore cells just prior to sporulation. These vesicles are not observed after cells are stimulated to release AcbA but remain visible after stimulation in cells lacking the Golgi reassembly stacking protein (GRASP). Acyl-CoA binding is required for the inclusion of AcbA in these vesicles, and the secretion of AcbA requires N-ethylmaleimide-sensitive factor (NSF). About 1% of the total cellular AcbA can be purified within membrane-bound vesicles. The yield of vesicles decreases dramatically when purified from wild-type cells that were stimulated to release AcbA, whereas the yield from GRASP mutant cells was only modestly altered by stimulation. We suggest that these AcbA-containing vesicles are secretion intermediates and that GRASP functions at a late step leading to the docking/fusion of these vesicles at the cell surface.

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