Asymmetric cell division in fucoid algae: a role for cortical adhesions in alignment of the mitotic apparatus

2001 ◽  
Vol 114 (23) ◽  
pp. 4319-4328
Author(s):  
Sherryl R. Bisgrove ◽  
Darryl L. Kropf
Keyword(s):  
Cell Division ◽  
Asymmetric Cell Division ◽  
Cell Cortex ◽  
Mitotic Apparatus ◽  
Pharmacological Agents ◽  
Division Plane ◽  
Adhesion Sites ◽  
Spindle Poles ◽  
Pelvetia Compressa ◽  
Two Phases

The first cell division in zygotes of the fucoid brown alga Pelvetia compressa is asymmetric and we are interested in the mechanism controlling the alignment of this division. Since the division plane bisects the mitotic apparatus, we investigated the timing and mechanism of spindle alignments. Centrosomes, which give rise to spindle poles, aligned with the growth axis in two phases – a premetaphase rotation of the nucleus and centrosomes followed by a postmetaphase alignment that coincided with the separation of the mitotic spindle poles during anaphase and telophase. The roles of the cytoskeleton and cell cortex in the two phases of alignment were analyzed by treatment with pharmacological agents. Treatments that disrupted cytoskeleton or perturbed cortical adhesions inhibited pre-metaphase alignment and we propose that this rotational alignment is effected by microtubules anchored at cortical adhesion sites. Postmetaphase alignment was not affected by any of the treatments tested, and may be dependent on asymmetric cell morphology.

scholarly journals Cytoplasmic MTOCs control spindle orientation for asymmetric cell division in plants

2017 ◽  
Vol 114 (42) ◽  
pp. E8847-E8854 ◽  
Author(s):  
Ken Kosetsu ◽  
Takashi Murata ◽  
Moé Yamada ◽  
Momoko Nishina ◽  
Joanna Boruc ◽  
...  
Keyword(s):  
Cell Division ◽  
Asymmetric Cell Division ◽  
Physcomitrella Patens ◽  
De Novo ◽  
Critical Role ◽  
Fine Tuning ◽  
Spindle Orientation ◽  
Mitotic Apparatus ◽  
Division Plane ◽  
Division Axis

Proper orientation of the cell division axis is critical for asymmetric cell divisions that underpin cell differentiation. In animals, centrosomes are the dominant microtubule organizing centers (MTOC) and play a pivotal role in axis determination by orienting the mitotic spindle. In land plants that lack centrosomes, a critical role of a microtubular ring structure, the preprophase band (PPB), has been observed in this process; the PPB is required for orienting (before prophase) and guiding (in telophase) the mitotic apparatus. However, plants must possess additional mechanisms to control the division axis, as certain cell types or mutants do not form PPBs. Here, using live imaging of the gametophore of the moss Physcomitrella patens, we identified acentrosomal MTOCs, which we termed “gametosomes,” appearing de novo and transiently in the prophase cytoplasm independent of PPB formation. We show that gametosomes are dispensable for spindle formation but required for metaphase spindle orientation. In some cells, gametosomes appeared reminiscent of the bipolar MT “polar cap” structure that forms transiently around the prophase nucleus in angiosperms. Specific disruption of the polar caps in tobacco cells misoriented the metaphase spindles and frequently altered the final division plane, indicating that they are functionally analogous to the gametosomes. These results suggest a broad use of transient MTOC structures as the spindle orientation machinery in plants, compensating for the evolutionary loss of centrosomes, to secure the initial orientation of the spindle in a spatial window that allows subsequent fine-tuning of the division plane axis by the guidance machinery.

A 3D Multi-Phase Hydrodynamic Model for Cytokinesis of Eukaryotic Cells

2016 ◽  
Vol 19 (3) ◽  
pp. 663-681 ◽  
Author(s):  
Jia Zhao ◽  
Qi Wang
Keyword(s):  
Cell Division ◽  
Mitotic Cycle ◽  
Asymmetric Cell Division ◽  
Numerical Study ◽  
Eukaryotic Cells ◽  
Myosin Filament ◽  
Cell Cortex ◽  
Parent Cell ◽  
Division Plane ◽  
Multi Phase

AbstractIn the late stage of the mitotic cycle of eukaryotic cells, cytokinesis ensues during which a parent cell replicates its nucleus with the necessary genetical substances (i.e., DNAs and chromosomes) and splits into two similar offspring cells. This mitotic process involves complex chemical, biophysical andmechanical processes whose details are just beginning to be unfolded experimentally. In this paper, we propose a full 3-D hydrodynamical model using a phase field approach to study the cellular morphological change during cytokinesis. In this model, the force along the contracting ring induced by remodeling of actin-myosin filament on cell cortex layer at the division plane of the parent cell during cytokinesis, is approximated using a proxy force anchored on the newly formed nuclei. The symmetric or asymmetric cell division is simulated numerically with the model. Our numerical results show that the location of the division plane and the contracting force along the cytokinetic ring on the division plane are essential for the cell division. In addition, our numerical study also shows that, during cytokinesis, surface tension of the cell membrane also contributes to this process by retaining the morphological integrity of the offspring cells. This model and the accompanying numerical simulation tool provide a solid framework to build upon with more sophisticated whole cell models to probe the cell mitotic process.

scholarly journals Asymmetric cell division: Plane but not simple

2001 ◽  
Vol 11 (6) ◽  
pp. R233-R236 ◽  
Author(s):  
Paul N. Adler ◽  
Job Taylor
Keyword(s):  
Cell Division ◽  
Asymmetric Cell Division ◽  
Division Plane ◽  
Cell Division Plane

scholarly journals Ric-8A and Giα Recruit LGN, NuMA, and Dynein to the Cell Cortex To Help Orient the Mitotic Spindle

2010 ◽  
Vol 30 (14) ◽  
pp. 3519-3530 ◽  
Author(s):  
Geoffrey E. Woodard ◽  
Ning-Na Huang ◽  
Hyeseon Cho ◽  
Toru Miki ◽  
Gregory G. Tall ◽  
...  
Keyword(s):  
Cell Division ◽  
Mammalian Cell ◽  
Pertussis Toxin ◽  
Mitotic Spindle ◽  
Fluorescent Protein ◽  
Model Organisms ◽  
Cell Cortex ◽  
Nucleotide Exchange ◽  
Mitotic Apparatus ◽  
Signaling Complex

ABSTRACT In model organisms, resistance to inhibitors of cholinesterase 8 (Ric-8), a G protein α (Gα) subunit guanine nucleotide exchange factor (GEF), functions to orient mitotic spindles during asymmetric cell divisions; however, whether Ric-8A has any role in mammalian cell division is unknown. We show here that Ric-8A and Gαi function to orient the metaphase mitotic spindle of mammalian adherent cells. During mitosis, Ric-8A localized at the cell cortex, spindle poles, centromeres, central spindle, and midbody. Pertussis toxin proved to be a useful tool in these studies since it blocked the binding of Ric-8A to Gαi, thus preventing its GEF activity for Gαi. Linking Ric-8A signaling to mammalian cell division, treatment of cells with pertussis toxin, reduction of Ric-8A expression, or decreased Gαi expression similarly affected metaphase cells. Each treatment impaired the localization of LGN (GSPM2), NuMA (microtubule binding nuclear mitotic apparatus protein), and dynein at the metaphase cell cortex and disturbed integrin-dependent mitotic spindle orientation. Live cell imaging of HeLa cells expressing green fluorescent protein-tubulin also revealed that reduced Ric-8A expression prolonged mitosis, caused occasional mitotic arrest, and decreased mitotic spindle movements. These data indicate that Ric-8A signaling leads to assembly of a cortical signaling complex that functions to orient the mitotic spindle.

scholarly journals Evidence for dynein and astral microtubule–mediated cortical release and transport of Gαi/LGN/NuMA complex in mitotic cells

2013 ◽  
Vol 24 (7) ◽  
pp. 901-913 ◽  
Author(s):  
Zhen Zheng ◽  
Qingwen Wan ◽  
Jing Liu ◽  
Huabin Zhu ◽  
Xiaogang Chu ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Fluorescence Recovery After Photobleaching ◽  
Cytoplasmic Dynein ◽  
Cell Cortex ◽  
Mitotic Apparatus ◽  
Spindle Positioning ◽  
Spindle Poles ◽  
Astral Microtubule ◽  
Mammalian Homologue ◽  
Cortical Localization

Spindle positioning is believed to be governed by the interaction between astral microtubules and the cell cortex and involve cortically anchored motor protein dynein. How dynein is recruited to and regulated at the cell cortex to generate forces on astral microtubules is not clear. Here we show that mammalian homologue of Drosophila Pins (Partner of Inscuteable) (LGN), a Gαi-binding protein that is critical for spindle positioning in different systems, associates with cytoplasmic dynein heavy chain (DYNC1H1) in a Gαi-regulated manner. LGN is required for the mitotic cortical localization of DYNC1H1, which, in turn, also modulates the cortical accumulation of LGN. Using fluorescence recovery after photobleaching analysis, we show that cortical LGN is dynamic and the turnover of LGN relies, at least partially, on astral microtubules and DYNC1H1. We provide evidence for dynein- and astral microtubule–mediated transport of Gαi/LGN/nuclear mitotic apparatus (NuMA) complex from cell cortex to spindle poles and show that actin filaments counteract such transport by maintaining Gαi/LGN/NuMA and dynein at the cell cortex. Our results indicate that astral microtubules are required for establishing bipolar, symmetrical cortical LGN distribution during metaphase. We propose that regulated cortical release and transport of LGN complex along astral microtubules may contribute to spindle positioning in mammalian cells.

scholarly journals Moesin is involved in polarity maintenance and cortical remodeling during asymmetric cell division

2018 ◽  
Vol 29 (4) ◽  
pp. 419-434 ◽  
Author(s):  
Namal Abeysundara ◽  
Andrew J. Simmonds ◽  
Sarah C. Hughes
Keyword(s):  
Cell Division ◽  
Cell Size ◽  
Asymmetric Cell Division ◽  
Developing Brain ◽  
Actin Binding ◽  
Cell Cortex ◽  
Asymmetric Distribution ◽  
Mitotic Progression ◽  
Apical Polarity ◽  
Size Asymmetry

An intact actomyosin network is essential for anchoring polarity proteins to the cell cortex and maintaining cell size asymmetry during asymmetric cell division of Drosophila neuroblasts (NBs). However, the mechanisms that control changes in actomyosin dynamics during asymmetric cell division remain unclear. We find that the actin-binding protein, Moesin, is essential for NB proliferation and mitotic progression in the developing brain. During metaphase, phosphorylated Moesin (p-Moesin) is enriched at the apical cortex, and loss of Moesin leads to defects in apical polarity maintenance and cortical stability. This asymmetric distribution of p-Moesin is determined by components of the apical polarity complex and Slik kinase. During later stages of mitosis, p-Moesin localization shifts more basally, contributing to asymmetric cortical extension and myosin basal furrow positioning. Our findings reveal Moesin as a novel apical polarity protein that drives cortical remodeling of dividing NBs, which is essential for polarity maintenance and initial establishment of cell size asymmetry.

scholarly journals Plk1 regulates spindle orientation by phosphorylating NuMA in human cells

2018 ◽  
Vol 1 (6) ◽  
pp. e201800223 ◽  
Author(s):  
Shrividya Sana ◽  
Riya Keshri ◽  
Ashwathi Rajeevan ◽  
Sukriti Kapoor ◽  
Sachin Kotak
Keyword(s):  
Cell Division ◽  
Mitotic Spindle ◽  
Molecular Mechanisms ◽  
Spindle Pole ◽  
Spindle Orientation ◽  
Cell Cortex ◽  
Division Plane ◽  
Evolutionarily Conserved ◽  
Cortical Localization ◽  
Proper Orientation

Proper orientation of the mitotic spindle defines the correct division plane and is essential for accurate cell division and development. In metazoans, an evolutionarily conserved complex comprising of NuMA/LGN/Gαi regulates proper orientation of the mitotic spindle by orchestrating cortical dynein levels during metaphase. However, the molecular mechanisms that modulate the spatiotemporal dynamics of this complex during mitosis remain elusive. Here, we report that acute inactivation of Polo-like kinase 1 (Plk1) during metaphase enriches cortical levels of dynein/NuMA/LGN and thus influences spindle orientation. We establish that this impact of Plk1 on cortical levels of dynein/NuMA/LGN is through NuMA, but not via dynein/LGN. Moreover, we reveal that Plk1 inhibition alters the dynamic behavior of NuMA at the cell cortex. We further show that Plk1 directly interacts and phosphorylates NuMA. Notably, NuMA-phosphorylation by Plk1 impacts its cortical localization, and this is needed for precise spindle orientation during metaphase. Overall, our finding connects spindle-pole pool of Plk1 with cortical NuMA and answers a long-standing puzzle about how spindle-pole Plk1 gradient dictates proper spindle orientation for error-free mitosis.

scholarly journals Canoe binds RanGTP to promote PinsTPR/Mud-mediated spindle orientation

2011 ◽  
Vol 195 (3) ◽  
pp. 369-376 ◽  
Author(s):  
Brett Wee ◽  
Christopher A. Johnston ◽  
Kenneth E. Prehoda ◽  
Chris Q. Doe
Keyword(s):  
Asymmetric Cell Division ◽  
Scaffolding Protein ◽  
Spindle Orientation ◽  
Cell Cortex ◽  
Tetratricopeptide Repeat ◽  
Epithelial Tissue ◽  
Mitotic Apparatus ◽  
Tissue Integrity ◽  
Interaction Partners ◽  
Tpr Domain

Regulated spindle orientation maintains epithelial tissue integrity and stem cell asymmetric cell division. In Drosophila melanogaster neural stem cells (neuroblasts), the scaffolding protein Canoe (Afadin/Af-6 in mammals) regulates spindle orientation, but its protein interaction partners and mechanism of action are unknown. In this paper, we use our recently developed induced cell polarity system to dissect the molecular mechanism of Canoe-mediated spindle orientation. We show that a previously uncharacterized portion of Canoe directly binds the Partner of Inscuteable (Pins) tetratricopeptide repeat (TPR) domain. The Canoe–PinsTPR interaction recruits Canoe to the cell cortex and is required for activation of the PinsTPR-Mud (nuclear mitotic apparatus in mammals) spindle orientation pathway. We show that the Canoe Ras-association (RA) domains directly bind RanGTP and that both the CanoeRA domains and RanGTP are required to recruit Mud to the cortex and activate the Pins/Mud/dynein spindle orientation pathway.

scholarly journals Ends and middle: global force balance determines septum location in fission yeast

2019 ◽  
Author(s):  
Xavier Le Goff ◽  
Jordi Comelles ◽  
Charles Kervrann ◽  
Daniel Riveline
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Asymmetric Cell Division ◽  
Quantitative Imaging ◽  
Force Balance ◽  
Radius Of Curvature ◽  
Division Plane ◽  
Division Site ◽  
Global Force ◽  
Scaling Arguments

AbstractThe fission yeast cell is shaped as a very regular cylinder ending by hemi-spheres at both cell ends. Its conserved phenotypes are often used as read-outs for classifying interacting genes and protein networks. Using Pascal and Young-Laplace laws, we proposed a framework where scaling arguments predicted shapes. Here we probed quantitatively one of these relations which predicts that the division site would be located closer to the cell end with the larger radius of curvature. By combining genetics and quantitative imaging, we tested experimentally whether altered shapes of cell end correlate with a displaced division site, leading to asymmetric cell division. Our results show that the division site position depends on the radii of curvatures of both ends. This new geometrical mechanism for the proper division plane positioning could be essential to achieve even partitioning of cellular material at each cell division.

scholarly journals Cell cortex microtubules contribute to division plane positioning during telophase in maize

2021 ◽  
Author(s):  
Marschal A. Bellinger ◽  
Aimee N. Uyehara ◽  
Pablo Martinez ◽  
Michael C. McCarthy ◽  
Carolyn G. Rasmussen
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Cell Cortex ◽  
Cell Wall Formation ◽  
Division Plane ◽  
Specific Location ◽  
Division Site ◽  
Plant Cell Division ◽  
Defective Mutant ◽  
Transient Interactions

AbstractThe phragmoplast is a plant-specific microtubule and microfilament structure that forms during telophase to direct new cell wall formation. The phragmoplast expands towards a specific location at the cell cortex called the division site. How the phragmoplast accurately reaches the division site is currently unknown. We show that a previously uncharacterized microtubule arrays accumulated at the cell cortex. These microtubules were organized by transient interactions with division-site localized proteins and were then incorporated into the phragmoplast to guide it towards the division site. A phragmoplast-guidance defective mutant, tangled1, had aberrant cortical-telophase microtubule accumulation that correlated with phragmoplast positioning defects. Division-site localized proteins may promote proper division plane positioning by organizing the cortical-telophase microtubule array to guide the phragmoplast to the division site during plant cell division.One Sentence SummaryMicrotubules accumulate at the cell cortex and interact with the plant division machinery to direct its movement towards the division site.

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