Aurora/Ipl1p-related kinases, a new oncogenic family of mitotic serine-threonine kinases

During the past five years, a growing number of serine-threonine kinases highly homologous to the Saccharomyces cerevisiae Ipl1p kinase have been isolated in various organisms. A Drosophila melanogaster homologue, aurora, was the first to be isolated from a multicellular organism. Since then, several related kinases have been found in mammalian cells. They localise to the mitotic apparatus: in the centrosome, at the poles of the bipolar spindle or in the midbody. The kinases are necessary for completion of mitotic events such as centrosome separation, bipolar spindle assembly and chromosome segregation. Extensive research is now focusing on these proteins because the three human homologues are overexpressed in various primary cancers. Furthermore, overexpression of one of these kinases transforms cells. Because of the myriad of kinases identified, we suggest a generic name: Aurora/Ipl1p-related kinase (AIRK). We denote AIRKs with a species prefix and a number, e.g. HsAIRK1.

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A microtubule polymerase cooperates with the kinesin-6 motor and a microtubule cross-linker to promote bipolar spindle assembly in the absence of kinesin-5 and kinesin-14 in fission yeast

Molecular Biology of the Cell ◽

10.1091/mbc.e17-08-0497 ◽

2017 ◽

Vol 28 (25) ◽

pp. 3647-3659 ◽

Cited By ~ 23

Author(s):

Masashi Yukawa ◽

Tomoki Kawakami ◽

Masaki Okazaki ◽

Kazunori Kume ◽

Ngang Heok Tang ◽

...

Keyword(s):

Fission Yeast ◽

Chromosome Segregation ◽

Spindle Pole Body ◽

Spindle Assembly ◽

Spindle Pole ◽

Temperature Sensitive ◽

Bipolar Spindle ◽

Pole Body ◽

Cross Linker ◽

Spindle Elongation

Accurate chromosome segregation relies on the bipolar mitotic spindle. In many eukaryotes, spindle formation is driven by the plus-end–directed motor kinesin-5 that generates outward force to establish spindle bipolarity. Its inhibition leads to the emergence of monopolar spindles with mitotic arrest. Intriguingly, simultaneous inactivation of the minus-end–directed motor kinesin-14 restores spindle bipolarity in many systems. Here we show that in fission yeast, three independent pathways contribute to spindle bipolarity in the absence of kinesin-5/Cut7 and kinesin-14/Pkl1. One is kinesin-6/Klp9 that engages with spindle elongation once short bipolar spindles assemble. Klp9 also ensures the medial positioning of anaphase spindles to prevent unequal chromosome segregation. Another is the Alp7/TACC-Alp14/TOG microtubule polymerase complex. Temperature-sensitive alp7cut7pkl1 mutants are arrested with either monopolar or very short spindles. Forced targeting of Alp14 to the spindle pole body is sufficient to render alp7cut7pkl1 triply deleted cells viable and promote spindle assembly, indicating that Alp14-mediated microtubule polymerization from the nuclear face of the spindle pole body could generate outward force in place of Cut7 during early mitosis. The third pathway involves the Ase1/PRC1 microtubule cross-linker that stabilizes antiparallel microtubules. Our study, therefore, unveils multifaceted interplay among kinesin-dependent and -independent pathways leading to mitotic bipolar spindle assembly.

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The Drosophila Kinesin-like Protein KLP67A Is Essential for Mitotic and Male Meiotic Spindle Assembly

Molecular Biology of the Cell ◽

10.1091/mbc.e03-05-0342 ◽

2004 ◽

Vol 15 (1) ◽

pp. 121-131 ◽

Cited By ~ 58

Author(s):

Rita Gandhi ◽

Silvia Bonaccorsi ◽

Diana Wentworth ◽

Stephen Doxsey ◽

Maurizio Gatti ◽

...

Keyword(s):

Cell Division ◽

Chromosome Segregation ◽

Mutational Analysis ◽

Spindle Assembly ◽

Male Meiosis ◽

Meiotic Spindle ◽

Drosophila Cell ◽

Centrosome Separation ◽

Mutant Cells

We have performed a mutational analysis together with RNA interference to determine the role of the kinesin-like protein KLP67A in Drosophila cell division. During both mitosis and male meiosis, Klp67A mutations cause an increase in MT length and disrupt discrete aspects of spindle assembly, as well as cytokinesis. Mutant cells exhibit greatly enlarged metaphase spindle as a result of excessive MT polymerization. The analysis of both living and fixed cells also shows perturbations in centrosome separation, chromosome segregation, and central spindle assembly. These data demonstrate that the MT plus end-directed motor KLP67A is essential for spindle assembly during mitosis and male meiosis and suggest that the regulation of MT plus-end polymerization is a key determinant of spindle architecture throughout cell division.

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PP2A-B56 opposes Mps1 phosphorylation of Knl1 and thereby promotes spindle assembly checkpoint silencing

The Journal of Cell Biology ◽

10.1083/jcb.201406109 ◽

2014 ◽

Vol 206 (7) ◽

pp. 833-842 ◽

Cited By ~ 96

Author(s):

Antonio Espert ◽

Pelin Uluocak ◽

Ricardo Nunes Bastos ◽

Davinderpreet Mangat ◽

Philipp Graab ◽

...

Keyword(s):

Chromosome Segregation ◽

Mammalian Cells ◽

Feedback Loop ◽

Spindle Assembly Checkpoint ◽

Spindle Assembly ◽

Eukaryotic Cells ◽

Aurora B ◽

Safeguard Mechanism

The spindle assembly checkpoint (SAC) monitors correct attachment of chromosomes to microtubules, an important safeguard mechanism ensuring faithful chromosome segregation in eukaryotic cells. How the SAC signal is turned off once all the chromosomes have successfully attached to the spindle remains an unresolved question. Mps1 phosphorylation of Knl1 results in recruitment of the SAC proteins Bub1, Bub3, and BubR1 to the kinetochore and production of the wait-anaphase signal. SAC silencing is therefore expected to involve a phosphatase opposing Mps1. Here we demonstrate in vivo and in vitro that BubR1-associated PP2A-B56 is a key phosphatase for the removal of the Mps1-mediated Knl1 phosphorylations necessary for Bub1/BubR1 recruitment in mammalian cells. SAC silencing is thus promoted by a negative feedback loop involving the Mps1-dependent recruitment of a phosphatase opposing Mps1. Our findings extend the previously reported role for BubR1-associated PP2A-B56 in opposing Aurora B and suggest that BubR1-bound PP2A-B56 integrates kinetochore surveillance and silencing of the SAC.

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Dynein, Lis1 and CLIP-170 counteract Eg5-dependent centrosome separation during bipolar spindle assembly

The EMBO Journal ◽

10.1038/emboj.2008.242 ◽

2008 ◽

Vol 27 (24) ◽

pp. 3235-3245 ◽

Cited By ~ 104

Author(s):

Marvin E Tanenbaum ◽

Libor Macůrek ◽

Niels Galjart ◽

René H Medema

Keyword(s):

Spindle Assembly ◽

Bipolar Spindle ◽

Centrosome Separation

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Nek5 promotes centrosome integrity in interphase and loss of centrosome cohesion in mitosis

The Journal of Cell Biology ◽

10.1083/jcb.201412099 ◽

2015 ◽

Vol 209 (3) ◽

pp. 339-348 ◽

Cited By ~ 24

Author(s):

Suzanna L. Prosser ◽

Navdeep K. Sahota ◽

Laurence Pelletier ◽

Ciaran G. Morrison ◽

Andrew M. Fry

Keyword(s):

Cell Cycle ◽

Chromosome Segregation ◽

Cell Cycle Progression ◽

Primary Cilia ◽

Microtubule Nucleation ◽

Cycle Progression ◽

Spindle Formation ◽

Mitotic Entry ◽

Bipolar Spindle ◽

Centrosome Separation

Nek5 is a poorly characterized member of the NIMA-related kinase family, other members of which play roles in cell cycle progression and primary cilia function. Here, we show that Nek5, similar to Nek2, localizes to the proximal ends of centrioles. Depletion of Nek5 or overexpression of kinase-inactive Nek5 caused unscheduled separation of centrosomes in interphase, a phenotype also observed upon overexpression of active Nek2. However, separated centrosomes that resulted from Nek5 depletion remained relatively close together, exhibited excess recruitment of the centrosome linker protein rootletin, and had reduced levels of Nek2. In addition, Nek5 depletion led to loss of PCM components, including γ-tubulin, pericentrin, and Cdk5Rap2, with centrosomes exhibiting reduced microtubule nucleation. Upon mitotic entry, Nek5-depleted cells inappropriately retained centrosome linker components and exhibited delayed centrosome separation and defective chromosome segregation. Hence, Nek5 is required for the loss of centrosome linker proteins and enhanced microtubule nucleation that lead to timely centrosome separation and bipolar spindle formation in mitosis.

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Intrakinetochore stretch is associated with changes in kinetochore phosphorylation and spindle assembly checkpoint activity

The Journal of Cell Biology ◽

10.1083/jcb.200808130 ◽

2009 ◽

Vol 184 (3) ◽

pp. 373-381 ◽

Cited By ~ 181

Author(s):

Thomas J. Maresca ◽

Edward D. Salmon

Keyword(s):

Drosophila Melanogaster ◽

Green Fluorescent Protein ◽

Chromosome Segregation ◽

Mitotic Spindle ◽

Spindle Assembly Checkpoint ◽

Fluorescent Protein ◽

Spindle Assembly ◽

Centromeric Chromatin ◽

Cell Assays ◽

Green Fluorescent

Cells have evolved a signaling pathway called the spindle assembly checkpoint (SAC) to increase the fidelity of chromosome segregation by generating a “wait anaphase” signal until all chromosomes are properly aligned within the mitotic spindle. It has been proposed that tension generated by the stretch of the centromeric chromatin of bioriented chromosomes stabilizes kinetochore microtubule attachments and turns off SAC activity. Although biorientation clearly causes stretching of the centromeric chromatin, it is unclear whether the kinetochore is also stretched. To test whether intrakinetochore stretch occurs and is involved in SAC regulation, we developed a Drosophila melanogaster S2 cell line expressing centromere identifier–mCherry and Ndc80–green fluorescent protein to mark the inner and outer kinetochore domains, respectively. We observed stretching within kinetochores of bioriented chromosomes by monitoring both inter- and intrakinetochore distances in live cell assays. This intrakinetochore stretch is largely independent of a 30-fold variation in centromere stretch. Furthermore, loss of intrakinetochore stretch is associated with enhancement of 3F3/2 phosphorylation and SAC activation.

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Interaction of NuMA protein with the kinesin Eg5: its possible role in bipolar spindle assembly and chromosome alignment

Biochemical Journal ◽

10.1042/bj20121447 ◽

2013 ◽

Vol 451 (2) ◽

pp. 195-204 ◽

Cited By ~ 11

Author(s):

Yuko Iwakiri ◽

Sachiko Kamakura ◽

Junya Hayase ◽

Hideki Sumimoto

Keyword(s):

Spindle Assembly ◽

Cytoplasmic Dynein ◽

Mitotic Apparatus ◽

Bipolar Spindle ◽

Spindle Poles ◽

Interphase Cells ◽

Correct Alignment ◽

Spindle Microtubules

Bipolar spindle assembly in mitotic cells is a prerequisite to ensure correct alignment of chromosomes for their segregation to each daughter cell; spindle microtubules are tethered at plus ends to chromosomes and focused at minus ends to either of the two spindle poles. NuMA (nuclear mitotic apparatus protein) is present solely in the nucleus in interphase cells, but relocalizes during mitosis to the spindle poles to play a crucial role in spindle assembly via focusing spindle microtubules to each pole. In the present study we show that the kinesin-5 family motor Eg5 is a protein that directly interacts with NuMA, using a proteomics approach and various binding assays both in vivo and in vitro. During mitosis Eg5 appears to interact with NuMA in the vicinity of the spindle poles, whereas the interaction does not occur in interphase cells, where Eg5 is distributed throughout the cytoplasm but NuMA exclusively localizes to the nucleus. Slight, but significant, depletion of Eg5 in HeLa cells by RNA interference results in formation of less-focused spindle poles with misaligned chromosomes in metaphase; these phenotypes are similar to those induced by depletion of NuMA. Since NuMA is less accumulated at the spindle poles in Eg5-depleted cells, Eg5 probably contributes to spindle assembly via regulating NuMA localization. Furthermore, depletion of cytoplasmic dynein induces mislocalization of NuMA and phenotypes similar to those observed in NuMA-depleted cells, without affecting Eg5 localization to the spindles. Thus dynein appears to control NuMA function in conjunction with Eg5.

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Two Saccharomyces cerevisiae kinesin-related gene products required for mitotic spindle assembly.

The Journal of Cell Biology ◽

10.1083/jcb.118.1.109 ◽

1992 ◽

Vol 118 (1) ◽

pp. 109-120 ◽

Cited By ~ 241

Author(s):

M A Hoyt ◽

L He ◽

K K Loo ◽

W S Saunders

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Viability ◽

Chromosome Segregation ◽

Heavy Chain ◽

Mitotic Spindle ◽

Spindle Assembly ◽

Gene Products ◽

Related Gene ◽

Mitotic Spindle Assembly ◽

Spindle Microtubules

Two Saccharomyces cerevisiae genes, CIN8 and KIP1 (a.k.a. CIN9), were identified by their requirement for normal chromosome segregation. Both genes encode polypeptides related to the heavy chain of the microtubule-based force-generating enzyme kinesin. Cin8p was found to be required for pole separation during mitotic spindle assembly at 37 degrees C, although overproduced Kip1p could substitute. At lower temperatures, the activity of at least one of these proteins was required for cell viability, indicating that they perform an essential but redundant function. Cin8p was observed to be a component of the mitotic spindle, colocalizing with the microtubules that lie between the poles. Taken together, these findings suggest that these proteins interact with spindle microtubules to produce an outwardly directed force acting upon the poles.

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The deubiquitinating enzyme complex BRISC is required for proper mitotic spindle assembly in mammalian cells

The Journal of Cell Biology ◽

10.1083/jcb.201503039 ◽

2015 ◽

Vol 210 (2) ◽

pp. 209-224 ◽

Cited By ~ 33

Author(s):

Kaowen Yan ◽

Li Li ◽

Xiaojian Wang ◽

Ruisha Hong ◽

Ying Zhang ◽

...

Keyword(s):

Mitotic Spindle ◽

Mammalian Cells ◽

Critical Role ◽

Spindle Assembly ◽

Mitotic Division ◽

Deubiquitinating Enzymes ◽

Mitotic Apparatus ◽

Protein Ubiquitination ◽

Assembly Factor ◽

Mitotic Spindle Assembly

Deubiquitinating enzymes (DUBs) negatively regulate protein ubiquitination and play an important role in diverse physiological processes, including mitotic division. The BRCC36 isopeptidase complex (BRISC) is a DUB that is specific for lysine 63–linked ubiquitin hydrolysis; however, its biological function remains largely undefined. Here, we identify a critical role for BRISC in the control of mitotic spindle assembly in cultured mammalian cells. BRISC is a microtubule (MT)-associated protein complex that predominantly localizes to the minus ends of K-fibers and spindle poles and directly binds to MTs; importantly, BRISC promotes the assembly of functional bipolar spindle by deubiquitinating the essential spindle assembly factor nuclear mitotic apparatus (NuMA). The deubiquitination of NuMA regulates its interaction with dynein and importin-β, which are required for its function in spindle assembly. Collectively, these results uncover BRISC as an important regulator of the mitotic spindle assembly and cell division, and have important implications for the development of anticancer drugs targeting BRISC.

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