scholarly journals Mitotic kinase CDK1 cooperates with polo kinase to ensure the temporal regulation of kinetochore microtubule dynamics and spindle checkpoint (802.14)

2014 ◽  
Vol 28 (S1) ◽  
Author(s):  
Huijuan Yu ◽  
Xiaoxuan Zhuang ◽  
Fei Mo ◽  
Guowei Fang ◽  
Xuebiao Yao
Keyword(s):  
Spindle Checkpoint ◽  
Microtubule Dynamics ◽  
Temporal Regulation ◽  
Mitotic Kinase ◽  
Polo Kinase

Cdc28-Clb mitotic kinase negatively regulates bud site assembly in the budding yeast

2001 ◽  
Vol 114 (1) ◽  
pp. 207-218 ◽  
Author(s):  
C.G. Padmashree ◽  
U. Surana
Keyword(s):  
Kinase Activity ◽  
Budding Yeast ◽  
Critical Role ◽  
The Other ◽  
Yeast Saccharomyces Cerevisiae ◽  
Bud Formation ◽  
Temporal Regulation ◽  
Mitotic Kinase ◽  
Cortical Localization ◽  
Bud Site

In the budding yeast Saccharomyces cerevisiae, a prospective mother normally commences the formation of a daughter (the bud) only in the G(1) phase of the cell division cycle. This suggests a strict temporal regulation of the processes that initiate the formation of a new bud. Using cortical localization of bud site components Spa2 and Bni1 as an indicator of bud site assembly, we show that cells assemble a bud site following inactivation of the Cdc28-Clb mitotic kinase but prior to START. Interestingly, an untimely inactivation of the mitotic kinase is sufficient to drive cells to assemble a new bud site inappropriately in G(2) or M phases. The induction of Cdc28/Clb kinase activity in G(1), on the other hand, dramatically reduces a cell's ability to construct an incipient bud site. Our findings strongly suggest that the Cdc28-Clb kinase plays a critical role in the mechanism that restricts the timing of bud formation to the G(1) phase of the cell cycle.

Pharicin a, a Novel Natural Compound That Induces Mitotic Arrest and Catastrophe of Cancer Cells by Perturbing Microtubule Dynamics and the Spindle Checkpoint

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4723-4723
Author(s):  
Guo-Qiang Chen ◽  
Wei Dai ◽  
Han-Zhang Xu ◽  
Dao Li
Keyword(s):  
Functional Characterization ◽  
Folk Medicine ◽  
Spindle Checkpoint ◽  
Mitotic Arrest ◽  
Spindle Pole ◽  
Microtubule Dynamics ◽  
Jurkat Cells ◽  
Cancer Drug

Abstract Microtubule poisons such as taxol represent a potent and effective class of anticancer compounds. In the past decades, great efforts have been directed to identify novel natural products with a mode of action similar to taxol but with a minimal side effect. In this study, we report the functional characterization of a new ent-kaurene diterpenoid termed pharicin A, which was originally isolated from Isodon pharicus leaves, a perennial shrub frequently used in Chinese folk medicine for tumor treatment. Pharicin A induces mitotic arrest in Jurkat, Raji and HeLa based on their morphology, DNA content, histone H3 serine-10 phosphorylation, and mitotic marker protein analyses. Pharicin A stabilizes the formation of mitotic spindles, which is coupled with a rapid accumulation of Cdc20 as well as an increased phosphorylation of Cdc27 and BubR1. Pharicin A treatment also results in an enhanced interaction between Cdc20 and spindle checkpoint components including Mad2 and BubR1. Moreover, pharicin A-induced mitotic arrest in HeLa cells is tightly associated with the presence of lagging/missegregated chromosomes at spindle pole regions, which are highly enriched in BubR1, CENP-E and Sgo1. Although pharicin A stabilizes microtubules both in vitro and in vivo, it induces mitotic arrest in taxol-resistant Jurkat cells. Combined, our study strongly suggests that pharicin A represents a novel class of small molecule compounds capable of perturbing microtubule dynamics and the spindle checkpoint in tumor cells, which merits further preclinical and clinical investigations for cancer drug development.

scholarly journals EB1 Targets to Kinetochores with Attached, Polymerizing Microtubules

2002 ◽  
Vol 13 (12) ◽  
pp. 4308-4316 ◽  
Author(s):  
Jennifer S. Tirnauer ◽  
Julie C. Canman ◽  
E.D. Salmon ◽  
Timothy J. Mitchison
Keyword(s):  
Spindle Checkpoint ◽  
Time Lapse ◽  
Microtubule Dynamics ◽  
Microtubule Polymerization ◽  
Spindle Microtubules ◽  
Chromosome Movements

Microtubule polymerization dynamics at kinetochores is coupled to chromosome movements, but its regulation there is poorly understood. The plus end tracking protein EB1 is required both for regulating microtubule dynamics and for maintaining a euploid genome. To address the role of EB1 in aneuploidy, we visualized its targeting in mitotic PtK1 cells. Fluorescent EB1, which localized to polymerizing ends of astral and spindle microtubules, was used to track their polymerization. EB1 also associated with a subset of attached kinetochores in late prometaphase and metaphase, and rarely in anaphase. Localization occurred in a narrow crescent, concave toward the centromere, consistent with targeting to the microtubule plus end–kinetochore interface. EB1 did not localize to kinetochores lacking attached kinetochore microtubules in prophase or early prometaphase, or upon nocodazole treatment. By time lapse, EB1 specifically targeted to kinetochores moving antipoleward, coupled to microtubule plus end polymerization, and not during plus end depolymerization. It localized independently of spindle bipolarity, the spindle checkpoint, and dynein/dynactin function. EB1 is the first protein whose targeting reflects kinetochore directionality, unlike other plus end tracking proteins that show enhanced kinetochore binding in the absence of microtubules. Our results suggest EB1 may modulate kinetochore microtubule polymerization and/or attachment.

scholarly journals Inhibition of Aurora B Kinase Blocks Chromosome Segregation, Overrides the Spindle Checkpoint, and Perturbs Microtubule Dynamics in Mitosis

2002 ◽  
Vol 12 (11) ◽  
pp. 900-905 ◽  
Author(s):  
Marko J. Kallio ◽  
Mark L. McCleland ◽  
P.Todd Stukenberg ◽  
Gary J. Gorbsky
Keyword(s):  
Chromosome Segregation ◽  
Spindle Checkpoint ◽  
Microtubule Dynamics ◽  
Aurora B ◽  
Aurora B Kinase

scholarly journals Phosphorylation of Microtubule-binding Protein Hec1 by Mitotic Kinase Aurora B Specifies Spindle Checkpoint Kinase Mps1 Signaling at the Kinetochore

2013 ◽  
Vol 288 (50) ◽  
pp. 36149-36159 ◽  
Author(s):  
Tongge Zhu ◽  
Zhen Dou ◽  
Bo Qin ◽  
Changjiang Jin ◽  
Xinghui Wang ◽  
...  
Keyword(s):  
Binding Protein ◽  
Spindle Checkpoint ◽  
Aurora B ◽  
Checkpoint Kinase ◽  
Microtubule Binding ◽  
Mitotic Kinase

scholarly journals Cyclin B interaction with microtubule-associated protein 4 (MAP4) targets p34cdc2 kinase to microtubules and is a potential regulator of M-phase microtubule dynamics.

1995 ◽  
Vol 128 (5) ◽  
pp. 849-862 ◽  
Author(s):  
K Ookata ◽  
S Hisanaga ◽  
J C Bulinski ◽  
H Murofushi ◽  
H Aizawa ◽  
...  
Keyword(s):  
Microtubule Dynamics ◽  
Cyclin B ◽  
Microtubule Associated Proteins ◽  
Mitotic Kinase ◽  
Culture Cells ◽  
Tissue Culture Cells ◽  
Detergent Extraction ◽  
M Phase ◽  
Associated Proteins ◽  
Free Microtubules

We previously demonstrated (Ookata et al., 1992, 1993) that the p34cdc2/cyclin B complex associates with microtubules in the mitotic spindle and premeiotic aster in starfish oocytes, and that microtubule-associated proteins (MAPs) might be responsible for this interaction. In this study, we have investigated the mechanism by which p34cdc2 kinase associates with the microtubule cytoskeleton in primate tissue culture cells whose major MAP is known to be MAP4. Double staining of primate cells with anti-cyclin B and anti-MAP4 antibodies demonstrated these two antigens were colocalized on microtubules and copartitioned following two treatments that altered MAP4 distribution. Detergent extraction before fixation removed cyclin B as well as MAP4 from the microtubules. Depolymerization of some of the cellular microtubules with nocodazole preferentially retained the microtubule localization of both cyclin B and MAP4. The association of p34cdc2/cyclin B kinase with microtubules was also shown biochemically to be mediated by MAP4. Cosedimentation of purified p34cdc2/cyclin B with purified microtubule proteins containing MAP4, but not with MAP-free microtubules, as well as binding of MAP4 to GST-cyclin B fusion proteins, demonstrated an interaction between cyclin B and MAP4. Using recombinant MAP4 fragments, we demonstrated that the Pro-rich C-terminal region of MAP4 is sufficient to mediate the cyclin B-MAP4 interaction. Since p34cdc2/cyclin B physically associated with MAP4, we examined the ability of the kinase complex to phosphorylate MAP4. Incubation of a ternary complex of p34cdc2, cyclin B, and the COOH-terminal domain of MAP4, PA4, with ATP resulted in intracomplex phosphorylation of PA4. Finally, we tested the effects of MAP4 phosphorylation on microtubule dynamics. Phosphorylation of MAP4 by p34cdc2 kinase did not prevent its binding to microtubules, but abolished its microtubule stabilizing activity. Thus, the cyclin B/MAP4 interaction we have described may be important in targeting the mitotic kinase to appropriate cytoskeletal substrates, for the regulation of spindle assembly and dynamics.

scholarly journals TAO1 kinase maintains chromosomal stability by facilitating proper congression of chromosomes

Open Biology ◽  
2014 ◽  
Vol 4 (6) ◽  
pp. 130108 ◽  
Author(s):  
Roshan L. Shrestha ◽  
Naoka Tamura ◽  
Anna Fries ◽  
Nicolas Levin ◽  
Joanna Clark ◽  
...  
Keyword(s):  
Error Correction ◽  
Chromosomal Instability ◽  
Spindle Checkpoint ◽  
Human Cells ◽  
Microtubule Dynamics ◽  
Regulatory Pathways ◽  
Chromosomal Stability ◽  
Microtubule Attachment ◽  
Drug Treatments

Chromosomal instability can arise from defects in chromosome–microtubule attachment. Using a variety of drug treatments, we show that TAO1 kinase is required for ensuring the normal congression of chromosomes. Depletion of TAO1 reduces the density of growing interphase and mitotic microtubules in human cells, showing TAO1's role in controlling microtubule dynamics. We demonstrate the aneugenic nature of chromosome–microtubule attachment defects in TAO1-depleted cells using an error-correction assay. Our model further strengthens the emerging paradigm that microtubule regulatory pathways are important for resolving erroneous kinetochore–microtubule attachments and maintaining the integrity of the genome, regardless of the spindle checkpoint status.

scholarly journals A microtubule dynamics reconstitutional convention

2016 ◽  
Vol 215 (3) ◽  
pp. 305-307
Author(s):  
Kevin C. Slep
Keyword(s):  
Kinase Activity ◽  
Biological Process ◽  
Microtubule Dynamics ◽  
The Core ◽  
Polo Kinase ◽  
Cell Biol ◽  
In Vitro Reconstitution ◽  
Core Components

In vitro reconstitution is the fundamental test for identification of the core components of a biological process. In this issue, Moriwaki and Goshima (2016. J. Cell Biol. https://doi.org/10.1083/jcb.201604118) reconstitute all phases of microtubule dynamics through the inclusion of five key regulators and demonstrate that Polo kinase activity shifts the system from an interphase mode into an enhanced mitotic mode.

scholarly journals Polo-like kinase-1 regulates kinetochore–microtubule dynamics and spindle checkpoint silencing

2012 ◽  
Vol 198 (4) ◽  
pp. 491-499 ◽  
Author(s):  
Dan Liu ◽  
Olga Davydenko ◽  
Michael A. Lampson
Keyword(s):  
High Activity ◽  
Spindle Checkpoint ◽  
Mitotic Arrest ◽  
Microtubule Dynamics ◽  
Signaling Proteins ◽  
Dynamic Localization ◽  
Checkpoint Signaling ◽  
Microtubule Attachment

Polo-like kinase-1 (Plk1) is a highly conserved kinase with multiple mitotic functions. Plk1 localizes to prometaphase kinetochores and is reduced at metaphase kinetochores, similar to many checkpoint signaling proteins, but Plk1 is not required for spindle checkpoint function. Plk1 is also implicated in stabilizing kinetochore–microtubule attachments, but these attachments are most stable when kinetochore Plk1 levels are low at metaphase. Therefore, it is unclear how Plk1 function at kinetochores can be understood in the context of its dynamic localization. In this paper, we show that Plk1 activity suppresses kinetochore–microtubule dynamics to stabilize initial attachments in prometaphase, and Plk1 removal from kinetochores is necessary to maintain dynamic microtubules in metaphase. Constitutively targeting Plk1 to kinetochores maintained high activity at metaphase, leading to reduced interkinetochore tension and intrakinetochore stretch, a checkpoint-dependent mitotic arrest, and accumulation of microtubule attachment errors. Together, our data show that Plk1 dynamics at kinetochores control two critical mitotic processes: initially establishing correct kinetochore–microtubule attachments and subsequently silencing the spindle checkpoint.

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