scholarly journals Structure and Function of the Mitotic Spindle Pole.

1992 ◽  
Vol 32 (3) ◽  
pp. 103-109
Author(s):  
Ryoko Kuriyama
Keyword(s):  
Mitotic Spindle ◽  
Spindle Pole ◽  
Structure And Function ◽  
And Function ◽  
Mitotic Spindle Pole

scholarly journals LIM kinase1 regulates mitotic centrosome integrity via its activity on dynein light intermediate chains

Open Biology ◽  
2018 ◽  
Vol 8 (6) ◽  
pp. 170202 ◽  
Author(s):  
Sirong Ou ◽  
Mei-Hua Tan ◽  
Ting Weng ◽  
HoiYeung Li ◽  
Cheng-Gee Koh
Keyword(s):  
Protein Transport ◽  
Protein Localization ◽  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Centrosomal Protein ◽  
And Function ◽  
Cytoskeleton Dynamics ◽  
Dynein Light Intermediate Chains ◽  
Intermediate Chains ◽  
Mitotic Spindle Pole

Abnormal centrosome number and function have been implicated in tumour development. LIM kinase1 (LIMK1), a regulator of actin cytoskeleton dynamics, is found to localize at the mitotic centrosome. However, its role at the centrosome is not fully explored. Here, we report that LIMK1 depletion resulted in multi-polar spindles and defocusing of centrosomes, implicating its involvement in the regulation of mitotic centrosome integrity. LIMK1 could influence centrosome integrity by modulating centrosomal protein localization at the spindle pole. Interestingly, dynein light intermediate chains (LICs) are able to rescue the defects observed in LIMK1-depleted cells. We found that LICs are potential novel interacting partners and substrates of LIMK1 and that LIMK1 phosphorylation regulates cytoplasmic dynein function in centrosomal protein transport, which in turn impacts mitotic spindle pole integrity.

scholarly journals Synergistic role of fission yeast Alp16GCP6 and Mzt1MOZART1 in γ-tubulin complex recruitment to mitotic spindle pole bodies and spindle assembly

2016 ◽  
Vol 27 (11) ◽  
pp. 1753-1763 ◽  
Author(s):  
Hirohisa Masuda ◽  
Takashi Toda
Keyword(s):  
Fission Yeast ◽  
Mitotic Spindle ◽  
Spindle Assembly Checkpoint ◽  
Synthetic Lethality ◽  
Spindle Assembly ◽  
Spindle Pole ◽  
Microtubule Assembly ◽  
Spindle Microtubule ◽  
Spindle Pole Bodies ◽  
Mitotic Spindle Pole

In fission yeast, γ-tubulin ring complex (γTuRC)–specific components Gfh1GCP4, Mod21GCP5, and Alp16GCP6 are nonessential for cell growth. Of these deletion mutants, only alp16Δ shows synthetic lethality with temperature-sensitive mutants of Mzt1MOZART1, a component of the γTuRC required for recruitment of the complex to microtubule-organizing centers. γ-Tubulin small complex levels at mitotic spindle pole bodies (SPBs, the centrosome equivalent in fungi) and microtubule levels for preanaphase spindles are significantly reduced in alp16Δ cells but not in gfh1Δ or mod21Δ cells. Furthermore, alp16Δ cells often form monopolar spindles and frequently lose a minichromosome when the spindle assembly checkpoint is inactivated. Alp16GCP6 promotes Mzt1-dependent γTuRC recruitment to mitotic SPBs and enhances spindle microtubule assembly in a manner dependent on its expression levels. Gfh1GCP4 and Mod21GCP5 are not required for Alp16GCP6-dependent γTuRC recruitment. Mzt1 has an additional role in the activation of the γTuRC for spindle microtubule assembly. The ratio of Mzt1 to γTuRC levels for preanaphase spindles is higher than at other stages of the cell cycle. Mzt1 overproduction enhances spindle microtubule assembly without affecting γTuRC levels at mitotic SPBs. We propose that Alp16GCP6 and Mzt1 act synergistically for efficient bipolar spindle assembly to ensure faithful chromosome segregation.

The mitotic spindle pole

1996 ◽  
Author(s):  
Tirso A. E. Gaglio
Keyword(s):  
Mitotic Spindle ◽  
Spindle Pole ◽  
Mitotic Spindle Pole

scholarly journals Automated tracking of mitotic spindle pole positions shows that LGN is required for spindle rotation but not orientation maintenance

Cell Cycle ◽  
2013 ◽  
Vol 12 (16) ◽  
pp. 2643-2655 ◽  
Author(s):  
Adam M Corrigan ◽  
Roshan L Shrestha ◽  
Ihsan Zulkipli ◽  
Noriko Hiroi ◽  
Yingjun Liu ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Spindle Pole ◽  
Automated Tracking ◽  
Spindle Rotation ◽  
Mitotic Spindle Pole

scholarly journals Aurora-A inactivation causes mitotic spindle pole fragmentation by unbalancing microtubule-generated forces

2011 ◽  
Vol 10 (1) ◽  
pp. 131 ◽  
Author(s):  
Italia A Asteriti ◽  
Maria Giubettini ◽  
Patrizia Lavia ◽  
Giulia Guarguaglini
Keyword(s):  
Mitotic Spindle ◽  
Spindle Pole ◽  
Aurora A ◽  
Mitotic Spindle Pole

scholarly journals Chlamydia trachomatis Infection Causes Mitotic Spindle Pole Defects Independently from its Effects on Centrosome Amplification

Traffic ◽  
2011 ◽  
Vol 12 (7) ◽  
pp. 854-866 ◽  
Author(s):  
Andrea E. Knowlton ◽  
Heather M. Brown ◽  
Theresa S. Richards ◽  
Lauren A. Andreolas ◽  
Rahul K. Patel ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Mitotic Spindle ◽  
Spindle Pole ◽  
Centrosome Amplification ◽  
Chlamydia Trachomatis Infection ◽  
Mitotic Spindle Pole

scholarly journals A novel mitotic spindle pole component that originates from the cytoplasm during prophase.

1986 ◽  
Vol 103 (5) ◽  
pp. 1863-1872 ◽  
Author(s):  
P R Sager ◽  
N L Rothfield ◽  
J M Oliver ◽  
R D Berlin
Keyword(s):  
Mitotic Spindle ◽  
Spindle Pole ◽  
Early Prophase ◽  
Microtubule Organizing Center ◽  
Spindle Poles ◽  
Interphase Cells ◽  
Organizing Center ◽  
Mitotic Spindle Pole ◽  
Pole Component

Several unique aspects of mitotic spindle formation have been revealed by investigation of an autoantibody present in the serum of a patient with the CREST (calcinosis, Raynaud's phenomenon, esophageal dysmotility, schlerodacytyly, and telangiectasias) syndrome. This antibody was previously shown to label at the spindle poles of metaphase and anaphase cells and to be absent from interphase cells. We show here that the serum stained discrete cytoplasmic foci in early prophase cells and only later localized to the spindle poles. The cytoplasmic distribution of the antigen was also seen in nocodazole-arrested cells and prophase cells in populations treated with taxol. In normal and taxol-treated cells, the microtubules appeared to emanate from the cytoplasmic foci and polar stain, and in cells released from nocodazole block, microtubules regrew from antigen-containing centers. This characteristic distribution suggests that the antigen is part of a microtubule organizing center. Thus, we propose that a prophase originating polar antigen functions in spindle pole organization as a coalescing microtubule organizing center that is present only during mitosis. Characterization of the serum showed reactions with multiple proteins at 115, 110, 50, 36, 30, and 28 kD. However, affinity-eluted antibody from the 115/110-kD bands was shown to specifically label the spindle pole and cytosolic foci in prophase cells.

scholarly journals Differential responses of mitotic spindle pole formation to microtubule-stabilizing agents epothilones A and B at low concentrations

Cell Cycle ◽  
2008 ◽  
Vol 7 (4) ◽  
pp. 477-483 ◽  
Author(s):  
Shinji Sakaushi ◽  
Kumi Nishida ◽  
Takashi Fukada ◽  
Kaori Senda-Murata ◽  
Shigenori Oka ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Spindle Pole ◽  
Stabilizing Agents ◽  
Low Concentrations ◽  
Differential Responses ◽  
Mitotic Spindle Pole

scholarly journals Polewards microtubule flux in the mitotic spindle: evidence from photoactivation of fluorescence.

1989 ◽  
Vol 109 (2) ◽  
pp. 637-652 ◽  
Author(s):  
T J Mitchison
Keyword(s):  
Molecular Dynamics ◽  
Tissue Culture ◽  
Strong Evidence ◽  
Mitotic Spindle ◽  
Living Cells ◽  
Structure And Function ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
And Function ◽  
Spindle Structure

I have synthesized a novel derivative of carboxyfluorescein that is nonfluorescent, but can be converted to a fluorescent form by exposure to 365-nm light. This photoactivable, fluorescent probe was covalently attached to tubulin and microinjected into mitotic tissue culture cells, where it incorporated into functional spindles. To generate a fluorescent bar across the mitotic spindle, metaphase cells were irradiated with a slit microbeam. This bar decreased in intensity over the first minute, presumably due to turnover of nonkinetochore microtubules. The remaining fluorescent zones, now presumably restricted to kinetochore microtubules, moved polewards at 0.3-0.7 microns/min. This result provides strong evidence for polewards flux in kinetochore microtubules. In conjunction with earlier biotin-tubulin incorporation experiments (Mitchison, T. J., L. Evans, E. Schulze, and M. Kirschner. 1986. Cell. 45:515-527), I conclude that microtubules polymerize at kinetochores and depolymerize near the poles throughout metaphase. The significance of this observation for spindle structure and function is discussed. Local photoactivation of fluorescence should be a generally useful method for following molecular dynamics inside living cells.

scholarly journals Importin-β negatively regulates multiple aspects of mitosis including RANGAP1 recruitment to kinetochores

2012 ◽  
Vol 196 (4) ◽  
pp. 435-450 ◽  
Author(s):  
Emanuele Roscioli ◽  
Laura Di Francesco ◽  
Alessio Bolognesi ◽  
Maria Giubettini ◽  
Serena Orlando ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Binding Sites ◽  
Protein Import ◽  
Spindle Pole ◽  
Nuclear Pore ◽  
Microtubule Dynamic ◽  
Nuclear Envelope Breakdown ◽  
Microtubule Attachment ◽  
Importin Α ◽  
Mitotic Spindle Pole

Importin-β is the main vector for interphase nuclear protein import and plays roles after nuclear envelope breakdown. Here we show that importin-β regulates multiple aspects of mitosis via distinct domains that interact with different classes of proteins in human cells. The C-terminal region (which binds importin-α) inhibits mitotic spindle pole formation. The central region (harboring nucleoporin-binding sites) regulates microtubule dynamic functions and interaction with kinetochores. Importin-β interacts through this region with NUP358/RANBP2, which in turn binds SUMO-conjugated RANGAP1 in nuclear pores. We show that this interaction continues after nuclear pore disassembly. Overexpression of importin-β, or of the nucleoporin-binding region, inhibited RANGAP1 recruitment to mitotic kinetochores, an event that is known to require microtubule attachment and the exportin CRM1. Co-expressing either importin-β–interacting RANBP2 fragments, or CRM1, restored RANGAP1 to kinetochores and rescued importin-β–dependent mitotic dynamic defects. These results reveal previously unrecognized importin-β functions at kinetochores exerted via RANBP2 and opposed by CRM1.

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