scholarly journals B1‐type cyclins control microtubule organization during cell division in Arabidopsis

EMBO Reports ◽  
2021 ◽  
Author(s):  
Mariana Romeiro Motta ◽  
Xin’Ai Zhao ◽  
Martine Pastuglia ◽  
Katia Belcram ◽  
Farshad Roodbarkelari ◽  
...  
Keyword(s):  
Cell Division ◽  
Microtubule Organization

scholarly journals Cytokinesis and Midzone Microtubule Organization inCaenorhabditis elegans Require the Kinesin-like Protein ZEN-4

1998 ◽  
Vol 9 (8) ◽  
pp. 2037-2049 ◽  
Author(s):  
William B. Raich ◽  
Adrienne N. Moran ◽  
Joel H. Rothman ◽  
Jeff Hardin
Keyword(s):  
Cell Division ◽  
Null Allele ◽  
Time Lapse ◽  
Equatorial Region ◽  
Microtubule Organization ◽  
Dividing Cells ◽  
Spindle Midzone ◽  
Cross Links ◽  
Complete Cell

Members of the MKLP1 subfamily of kinesin motor proteins localize to the equatorial region of the spindle midzone and are capable of bundling antiparallel microtubules in vitro. Despite these intriguing characteristics, it is unclear what role these kinesins play in dividing cells, particularly within the context of a developing embryo. Here, we report the identification of a null allele ofzen-4, an MKLP1 homologue in the nematodeCaenorhabditis elegans, and demonstrate that ZEN-4 is essential for cytokinesis. Embryos deprived of ZEN-4 form multinucleate single-celled embryos as they continue to cycle through mitosis but fail to complete cell division. Initiation of the cytokinetic furrow occurs at the normal time and place, but furrow propagation halts prematurely. Time-lapse recordings and microtubule staining reveal that the cytokinesis defect is preceded by the dissociation of the midzone microtubules. We show that ZEN-4 protein localizes to the spindle midzone during anaphase and persists at the midbody region throughout cytokinesis. We propose that ZEN-4 directly cross-links the midzone microtubules and suggest that these microtubules are required for the completion of cytokinesis.

scholarly journals EB1 and EB3 regulate microtubule minus end organization and Golgi morphology

2017 ◽  
Vol 216 (10) ◽  
pp. 3179-3198 ◽  
Author(s):  
Chao Yang ◽  
Jingchao Wu ◽  
Cecilia de Heus ◽  
Ilya Grigoriev ◽  
Nalan Liv ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Lines ◽  
Protein Complexes ◽  
Focal Adhesions ◽  
Microtubule Organization ◽  
The Core ◽  
Microtubule Polymerization ◽  
Golgi Membranes ◽  
Core Components ◽  
Knockout Technology

End-binding proteins (EBs) are the core components of microtubule plus end tracking protein complexes, but it is currently unknown whether they are essential for mammalian microtubule organization. Here, by using CRISPR/Cas9-mediated knockout technology, we generated stable cell lines lacking EB2 and EB3 and the C-terminal partner-binding half of EB1. These cell lines show only mild defects in cell division and microtubule polymerization. However, the length of CAMSAP2-decorated stretches at noncentrosomal microtubule minus ends in these cells is reduced, microtubules are detached from Golgi membranes, and the Golgi complex is more compact. Coorganization of microtubules and Golgi membranes depends on the EB1/EB3–myomegalin complex, which acts as membrane–microtubule tether and counteracts tight clustering of individual Golgi stacks. Disruption of EB1 and EB3 also perturbs cell migration, polarity, and the distribution of focal adhesions. EB1 and EB3 thus affect multiple interphase processes and have a major impact on microtubule minus end organization.

scholarly journals The Plastid of Toxoplasma gondii Is Divided by Association with the Centrosomes

2000 ◽  
Vol 151 (7) ◽  
pp. 1423-1434 ◽  
Author(s):  
Boris Striepen ◽  
Michael J. Crawford ◽  
Michael K. Shaw ◽  
Lewis G. Tilney ◽  
Frank Seeber ◽  
...  
Keyword(s):  
Cell Division ◽  
Toxoplasma Gondii ◽  
Genetic Manipulation ◽  
Fluorescent Proteins ◽  
Recombinant Expression ◽  
Molecular Genetic ◽  
Time Lapse ◽  
Microtubule Organization ◽  
Apicomplexan Parasites ◽  
Daughter Cells

Apicomplexan parasites harbor a single nonphotosynthetic plastid, the apicoplast, which is essential for parasite survival. Exploiting Toxoplasma gondii as an accessible system for cell biological analysis and molecular genetic manipulation, we have studied how these parasites ensure that the plastid and its 35-kb circular genome are faithfully segregated during cell division. Parasite organelles were labeled by recombinant expression of fluorescent proteins targeted to the plastid and the nucleus, and time-lapse video microscopy was used to image labeled organelles throughout the cell cycle. Apicoplast division is tightly associated with nuclear and cell division and is characterized by an elongated, dumbbell-shaped intermediate. The plastid genome is divided early in this process, associating with the ends of the elongated organelle. A centrin-specific antibody demonstrates that the ends of dividing apicoplast are closely linked to the centrosomes. Treatment with dinitroaniline herbicides (which disrupt microtubule organization) leads to the formation of multiple spindles and large reticulate plastids studded with centrosomes. The mitotic spindle and the pellicle of the forming daughter cells appear to generate the force required for apicoplast division in Toxoplasma gondii. These observations are discussed in the context of autonomous and FtsZ-dependent division of plastids in plants and algae.

scholarly journals Critical role for cold shock protein YB-1 in cytokinesis

2020 ◽  
Author(s):  
Sunali Mehta ◽  
Michael Algie ◽  
Tariq Al-Jabri ◽  
Cushla McKinney ◽  
Srinivasaraghavan Kannan ◽  
...  
Keyword(s):  
Cell Division ◽  
Cancer Progression ◽  
Cold Shock ◽  
Binding Protein ◽  
Critical Role ◽  
Confocal Imaging ◽  
Cold Shock Protein ◽  
Microtubule Organization ◽  
Atomistic Modelling

ABSTRACTHigh levels of the cold shock protein Y-box-binding protein-1, YB-1, are tightly correlated with increased cell proliferation and cancer progression. However, the precise mechanism by which YB-1 regulates proliferation is unknown. Here, we found that YB-1 depletion in several cell lines resulted in cytokinesis failure, multinucleation and an increase in G1 transit time. Rescue experiments indicated that YB-1 was required for completion of cytokinesis. Using confocal imaging of cells undergoing cytokinesis both in vitro and in zebrafish embryos, we found that YB-1 was critical for microtubule organization during cytokinesis. Using mass spectrometry we identified multiple novel phosphorylation sites on YB-1. We show that phosphorylation of YB-1 at multiple serine residues was essential for its function during cytokinesis. Using atomistic modelling we show how multiple phosphorylations alter YB-1 conformation, allowing it to interact with protein partners. Our results establish phosphorylated YB-1 as a critical regulator of cytokinesis, defining for the first time precisely how YB-1 regulates cell division.SUMMARYY-box-binding protein-1, YB-1, is essential for cell division, but it is not clear how it functions. Using live imaging and confocal microscopy we show that YB-1 functions only in the last step of division, specifically being required to initiate cytokinesis.

scholarly journals Moesin and its activating kinase Slik are required for cortical stability and microtubule organization in mitotic cells

2008 ◽  
Vol 180 (4) ◽  
pp. 739-746 ◽  
Author(s):  
Sébastien Carreno ◽  
Ilektra Kouranti ◽  
Edith Szafer Glusman ◽  
Margaret T. Fuller ◽  
Arnaud Echard ◽  
...  
Keyword(s):  
Cell Division ◽  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
Cortical Actin ◽  
Microtubule Organization ◽  
Abnormal Distribution ◽  
Multistep Process ◽  
Cortical Contractility ◽  
Spatiotemporal Control ◽  
Shape Changes

Cell division requires cell shape changes involving the localized reorganization of cortical actin, which must be tightly linked with chromosome segregation operated by the mitotic spindle. How this multistep process is coordinated remains poorly understood. In this study, we show that the actin/membrane linker moesin, the single ERM (ezrin, radixin, and moesin) protein in Drosophila melanogaster, is required to maintain cortical stability during mitosis. Mitosis onset is characterized by a burst of moesin activation mediated by a Slik kinase–dependent phosphorylation. Activated moesin homogenously localizes at the cortex in prometaphase and is progressively restricted at the equator in later stages. Lack of moesin or inhibition of its activation destabilized the cortex throughout mitosis, resulting in severe cortical deformations and abnormal distribution of actomyosin regulators. Inhibiting moesin activation also impaired microtubule organization and precluded stable positioning of the mitotic spindle. We propose that the spatiotemporal control of moesin activation at the mitotic cortex provides localized cues to coordinate cortical contractility and microtubule interactions during cell division.

scholarly journals Altered chemomechanical coupling causes impaired motility of the kinesin-4 motors KIF27 and KIF7

2018 ◽  
Vol 217 (4) ◽  
pp. 1319-1334 ◽  
Author(s):  
Yang Yue ◽  
T. Lynne Blasius ◽  
Stephanie Zhang ◽  
Shashank Jariwala ◽  
Benjamin Walker ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Cell Division ◽  
Adenosine Triphosphate ◽  
Adenosine Triphosphatase ◽  
Adenosine Diphosphate ◽  
Microtubule Dynamics ◽  
Microtubule Organization ◽  
High Affinity ◽  
Chemomechanical Coupling ◽  
Mechanistic Basis

Kinesin-4 motors play important roles in cell division, microtubule organization, and signaling. Understanding how motors perform their functions requires an understanding of their mechanochemical and motility properties. We demonstrate that KIF27 can influence microtubule dynamics, suggesting a conserved function in microtubule organization across the kinesin-4 family. However, kinesin-4 motors display dramatically different motility characteristics: KIF4 and KIF21 motors are fast and processive, KIF7 and its Drosophila melanogaster homologue Costal2 (Cos2) are immotile, and KIF27 is slow and processive. Neither KIF7 nor KIF27 can cooperate for fast processive transport when working in teams. The mechanistic basis of immotile KIF7 behavior arises from an inability to release adenosine diphosphate in response to microtubule binding, whereas slow processive KIF27 behavior arises from a slow adenosine triphosphatase rate and a high affinity for both adenosine triphosphate and microtubules. We suggest that evolutionarily selected sequence differences enable immotile KIF7 and Cos2 motors to function not as transporters but as microtubule-based tethers of signaling complexes.

Distribution of tubulin and actin through the cell division cycle of the fission yeast Schizosaccharomyces japonicus var. versatilis: a comparison with Schizosaccharomyces pombe

1990 ◽  
Vol 96 (1) ◽  
pp. 71-77
Author(s):  
C.E. Alfa ◽  
J.S. Hyams
Keyword(s):  
Cell Division ◽  
Fission Yeast ◽  
Cell Biology ◽  
Cell Division Cycle ◽  
Microtubule Organization ◽  
Actin Ring ◽  
Western Blots ◽  
Cell Extracts ◽  
Tightly Coupled ◽  
Basic Studies

Changes in the distribution of microtubules and F-actin through the cell division cycle of the fission yeast Schizosaccharomyces japonicus var. versatilis were investigated by fluorescence microscopy. The fluorescence images obtained with S. japonicus were markedly superior to those previously reported for S. pombe and revealed new details of cytoskeletal organization in this important genus. As in S. pombe, F-actin in S. japonicus was present as a concentration of ‘dots’ at the growing poles of interphase cells and as a filamentous equatorial ring directing the deposition of the cytokinetic septum. The transition between these two states occurred at late anaphase, in contrast to the situation in S. pombe where the appearance of the equatorial actin ring is tightly coupled to the early events of mitosis. During the course of cytokinesis in S. japonicus the actin ring constricted and broadened, suggesting that it is contractile. Microtubule organization in S. japonicus also revealed interesting differences from S. pombe. Whereas in S. pombe cytoplasmic microtubules are reinitiated from a pair of microtubule organizing centres (MTOCs) at the cell equator, in S. japonicus they arise by extensive microtubule growth from the spindle poles. Western blots of cell extracts enriched for tubulin by DEAE-Sephadex chromatography showed that, like S. pombe, S. japonicus contains two alpha-tubulins and a single beta-tubulin. Whilst the alpha 1- and beta-tubulins from the two species comigrated on one-dimensional polyacrylamide gels, the alpha 2 species were electrophoretically distinct. Although fundamental differences clearly exist between the two species, S. japonicus could prove to be a useful tool in basic studies of fission yeast cell biology.

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