EML4 and NUDC in mitotic spindle formation

Reactome ◽  
2020 ◽  
Author(s):  
Susanne Bechstedt ◽  
Andrew M. Fry ◽  
Kellie J Lucken ◽  
Laura O'Regan
Keyword(s):  
Mitotic Spindle ◽  
Spindle Formation

Regulation of Microtubule Assembly: The View From The End

2000 ◽  
Vol 6 (S2) ◽  
pp. 80-81
Author(s):  
L. Cassimeris ◽  
C. Spittle ◽  
M. Kratzer
Keyword(s):  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
Dynamic Instability ◽  
Intrinsic Property ◽  
Microtubule Dynamics ◽  
Microtubule Assembly ◽  
Chromosome Movement ◽  
Spindle Formation ◽  
Associated Proteins

The mitotic spindle is responsible for chromosome movement during mitosis. It is composed of a dynamic array of microtubules and associated proteins whose assembly and constant turnover are required for both spindle formation and chromosome movement. Because microtubule assembly and turnover are necessary for chromosome segregation, we are studying how cells regulate microtubule dynamics. Microtubules are polarized polymers composed of tubulin subunits; they assemble by a process of dynamic instability where individual microtubules exist in persistent phases of elongation or rapid shortening with abrupt transitions between these two states. The switch from elongation to shortening is termed catastrophe, and the switch from shortening to elongation, rescue. Although dynamic instability is an intrinsic property of the tubulin subunits, cells use associated proteins to both speed elongation (∼ 10 fold) and regulate transitions.The only protein isolated to date capable of promoting fast polymerization consistent with rates in vivo is XMAP215, a 215 kD protein from Xenopus eggs.

The role ofSaccharomyces cerevisiae Cdc40p in DNA replication and mitotic spindle formation and/or maintenance

1995 ◽  
Vol 247 (2) ◽  
pp. 123-136 ◽  
Author(s):  
Nora Vaisman ◽  
Andrey Tsouladze ◽  
Kenneth Robzyk ◽  
Sigal Ben-Yehuda ◽  
Martin Kupiec ◽  
...  
Keyword(s):  
Dna Replication ◽  
Mitotic Spindle ◽  
Spindle Formation

Nucleophosmin is required for chromosome congression, proper mitotic spindle formation, and kinetochore-microtubule attachment in HeLa cells

FEBS Letters ◽  
2008 ◽  
Vol 582 (27) ◽  
pp. 3839-3844 ◽  
Author(s):  
Mohammed Abdullahel Amin ◽  
Sachihiro Matsunaga ◽  
Susumu Uchiyama ◽  
Kiichi Fukui
Keyword(s):  
Hela Cells ◽  
Mitotic Spindle ◽  
Spindle Formation ◽  
Microtubule Attachment ◽  
Chromosome Congression

scholarly journals Challenges In Modeling Chromosome-driven Mitotic Spindle Formation

2009 ◽  
Vol 96 (3) ◽  
pp. 505a
Author(s):  
Stuart Schaffner ◽  
Jorge V. Jose
Keyword(s):  
Mitotic Spindle ◽  
Spindle Formation

scholarly journals Differing requirements for Augmin in male meiotic and mitotic spindle formation in Drosophila

Open Biology ◽  
2014 ◽  
Vol 4 (5) ◽  
pp. 140047 ◽  
Author(s):  
Matthew S. Savoian ◽  
David M. Glover
Keyword(s):  
Mitotic Spindle ◽  
Cell Types ◽  
Male Meiosis ◽  
Negative Regulation ◽  
Mitotic Spindles ◽  
Animal Cells ◽  
Spindle Formation ◽  
Formation Pathway ◽  
Fixed Cell ◽  
Mitotic Cells

Animal cells divide using a microtubule-based, bipolar spindle. Both somatic, mitotic cells and sperm-producing male meiotic spermatocytes use centrosome-dependent and acentrosomal spindle-forming mechanisms. Here, we characterize the largely undefined, centrosome-independent spindle formation pathway used during male meiosis. Our live and fixed cell analyses of Drosophila spermatocytes reveal that acentrosomal microtubules are nucleated at kinetochores and in the vicinity of chromatin and that together these assemble into functional spindles. Mutational studies indicate that γ-tubulin and its extra-centrosomal targeting complex, Augmin, are vital for this process. In addition, Augmin facilitates efficient spindle assembly in the presence of centrosomes. In contrast to the pronounced recruitment of Augmin on spindles in other cell types, the complex is absent from those of spermatocytes but does accumulate on kinetochores. Polo kinase facilitates this kinetochore recruitment while inhibiting Augmin's spindle association, and this in turn dictates γ-tubulin distribution and spindle density. Polo's negative regulation of Augmin in male meiosis contrasts with its requirement in loading Augmin along mitotic spindles in somatic Drosophila cells. Together our data identify a novel mechanism of acentrosomal spindle formation in spermatocytes and reveal its divergence from that used in mitotic cells.

scholarly journals The Nek6 and Nek7 Protein Kinases Are Required for Robust Mitotic Spindle Formation and Cytokinesis

2009 ◽  
Vol 29 (14) ◽  
pp. 3975-3990 ◽  
Author(s):  
Laura O'Regan ◽  
Andrew M. Fry
Keyword(s):  
Mitotic Spindle ◽  
Spindle Assembly Checkpoint ◽  
Mitotic Spindles ◽  
Mitotic Progression ◽  
Serine Threonine Kinase ◽  
Spindle Formation ◽  
Spindle Poles ◽  
And Function ◽  
Interfering Rna ◽  
Reduced Activity

ABSTRACT Nek6 and Nek7 are members of the NIMA-related serine/threonine kinase family. Previous work showed that they contribute to mitotic progression downstream of another NIMA-related kinase, Nek9, although the roles of these different kinases remain to be defined. Here, we carried out a comprehensive analysis of the regulation and function of Nek6 and Nek7 in human cells. By generating specific antibodies, we show that both Nek6 and Nek7 are activated in mitosis and that interfering with their activity by either depletion or expression of reduced-activity mutants leads to mitotic arrest and apoptosis. Interestingly, while completely inactive mutants and small interfering RNA-mediated depletion delay cells at metaphase with fragile mitotic spindles, hypomorphic mutants or RNA interference treatment combined with a spindle assembly checkpoint inhibitor delays cells at cytokinesis. Importantly, depletion of either Nek6 or Nek7 leads to defective mitotic progression, indicating that although highly similar, they are not redundant. Indeed, while both kinases localize to spindle poles, only Nek6 obviously localizes to spindle microtubules in metaphase and anaphase and to the midbody during cytokinesis. Together, these data lead us to propose that Nek6 and Nek7 play independent roles not only in robust mitotic spindle formation but also potentially in cytokinesis.

Generation of GTP-bound Ran by RCC1 is required for chromatin-induced mitotic spindle formation

Nature ◽  
10.1038/22133 ◽  
1999 ◽  
Vol 400 (6740) ◽  
pp. 178-181 ◽  
Author(s):  
Rafael E. Carazo-Salas ◽  
Giulia Guarguaglini ◽  
Oliver J. Gruss ◽  
Alexandra Segref ◽  
Eric Karsenti ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Spindle Formation

scholarly journals RASSF7 Is a Member of a New Family of RAS Association Domain–containing Proteins and Is Required for Completing Mitosis

2008 ◽  
Vol 19 (4) ◽  
pp. 1772-1782 ◽  
Author(s):  
Victoria Sherwood ◽  
Ria Manbodh ◽  
Carol Sheppard ◽  
Andrew D. Chalmers
Keyword(s):  
Neural Tube ◽  
Mitotic Spindle ◽  
Tissue Growth ◽  
Dependent Manner ◽  
Tissue Architecture ◽  
Spindle Formation ◽  
Embryonic Tissues ◽  
New Family ◽  
Evolutionarily Conserved ◽  
New Protein

Mitosis is a fundamental feature of all cellular organisms. It must be tightly regulated to allow normal tissue growth and to prevent cancer formation. Here, we identify a new protein that is required for mitosis. We show that the Ras association (RA) domain–containing protein, RASSF7, is part of an evolutionarily conserved group of four proteins. These are RASSF7, RASSF8, and two new RASSF proteins P-CIP1/RASSF9 and RASSF10. We call this group the N-terminal RASSF family. We analyzed the function of Xenopus RASSF7. RASSF7 was found to be expressed in several embryonic tissues including the skin, eyes, and neural tube. Knocking down its function led to cells failing to form a mitotic spindle and arresting in mitosis. This caused nuclear breakdown, apoptosis, and a striking loss of tissue architecture in the neural tube. Consistent with a role in spindle formation, RASSF7 protein was found to localize to the centrosome. This localization occurred in a microtubule-dependent manner, demonstrating that there is a mutually dependant relationship between RASSF7 localization and spindle formation. Thus RASSF7, the first member of the N-terminal RASSF family to be functionally analyzed, is a centrosome-associated protein required to form a spindle and complete mitosis in the neural tube.

scholarly journals First mitotic spindle formation is led by sperm centrosome-dependent MTOCs in humans

Reproduction ◽  
2021 ◽  
Vol 161 (5) ◽  
pp. V19-V22
Author(s):  
Yoshiteru Kai ◽  
Hiroomi Kawano ◽  
Naoki Yamashita
Keyword(s):  
Mitotic Spindle ◽  
High Frequency ◽  
Point Of View ◽  
Cell Stage ◽  
Spindle Formation ◽  
Microtubule Organizing Centers ◽  
High Incidence

Unlike in mice, multinucleated blastomeres appear at a high frequency in the two-cell-stage embryos in humans. In this Point of View article, we demonstrate that the first mitotic spindle formation led by sperm centrosome-dependent microtubule organizing centers may cause a high incidence of zygotic division errors using human tripronuclear zygotes.

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