scholarly journals Complementation of fission yeast kinesin-5/Cut7 with human Eg5 provides a versatile platform for screening of anti-cancer compounds

Author(s):  
Woosang Hwang ◽  
Takashi Toda ◽  
Masashi Yukawa

Abstract Kinesin-5 family proteins are essential for bipolar spindle assembly to ensure mitotic fidelity. Here we demonstrate evolutionary functional conservation of kinesin-5 between human and fission yeast. Human Eg5 expressed in the nucleus replaces fission yeast counterpart Cut7. Intriguingly, Eg5 overproduction results in cytotoxicity. This phenotype provides a useful platform for the development of novel kinesin-5 inhibitors as anti-cancer drugs.

2017 ◽  
Vol 28 (25) ◽  
pp. 3647-3659 ◽  
Author(s):  
Masashi Yukawa ◽  
Tomoki Kawakami ◽  
Masaki Okazaki ◽  
Kazunori Kume ◽  
Ngang Heok Tang ◽  
...  

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.


2019 ◽  
Vol 30 (22) ◽  
pp. 2802-2813 ◽  
Author(s):  
Yutaka Shirasugi ◽  
Masamitsu Sato

Bipolar spindles are organized by motor proteins that generate microtubule-­dependent forces to separate the two spindle poles. The fission yeast Cut7 (kinesin-5) is a plus-end-directed motor that generates the outward force to separate the two spindle poles, whereas the minus-end-directed motor Pkl1 (kinesin-14) generates the inward force. Balanced forces by these antagonizing kinesins are essential for bipolar spindle organization in mitosis. Here, we demonstrate that chromosomes generate another outward force that contributes to the bipolar spindle assembly. First, it was noted that the cut7 pkl1 double knockout failed to separate spindle poles in meiosis I, although the mutant is known to succeed it in mitosis. It was assumed that this might be because meiotic kinetochores of bivalent chromosomes joined by cross-overs generate weaker tensions in meiosis I than the strong tensions in mitosis generated by tightly tethered sister kinetochores. In line with this idea, when meiotic mono-oriented kinetochores were artificially converted to a mitotic bioriented layout, the cut7 pkl1 mutant successfully separated spindle poles in meiosis I. Therefore, we propose that spindle pole separation is promoted by outward forces transmitted from kinetochores to spindle poles through microtubules.


Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1154 ◽  
Author(s):  
Masashi Yukawa ◽  
Yasuhiro Teratani ◽  
Takashi Toda

The bipolar mitotic spindle drives accurate chromosome segregation by capturing the kinetochore and pulling each set of sister chromatids to the opposite poles. In this review, we describe recent findings on the multiple pathways leading to bipolar spindle formation in fission yeast and discuss these results from a broader perspective. The roles of three mitotic kinesins (Kinesin-5, Kinesin-6 and Kinesin-14) in spindle assembly are depicted, and how a group of microtubule-associated proteins, sister chromatid cohesion and the kinetochore collaborate with these motors is shown. We have paid special attention to the molecular pathways that render otherwise essential Kinesin-5 to become non-essential: how cells build bipolar mitotic spindles without the need for Kinesin-5 and where the alternate forces come from are considered. We highlight the force balance for bipolar spindle assembly and explain how outward and inward forces are generated by various ways, in which the proper fine-tuning of microtubule dynamics plays a crucial role. Overall, these new pathways have illuminated the remarkable plasticity and adaptability of spindle mechanics. Kinesin molecules are regarded as prospective targets for cancer chemotherapy and many specific inhibitors have been developed. However, several hurdles have arisen against their clinical implementation. This review provides insight into possible strategies to overcome these challenges.


1993 ◽  
Vol 55 (1) ◽  
pp. 43-46
Author(s):  
Jun YOSHIDA ◽  
Juichiro NAKAYAMA ◽  
Nobuyuki SHIMIZU ◽  
Shonosuke NAGAE ◽  
Yoshiaki HORI

2019 ◽  
Vol 24 (32) ◽  
pp. 3829-3841 ◽  
Author(s):  
Lakshmanan Loganathan ◽  
Karthikeyan Muthusamy

Worldwide, colorectal cancer takes up the third position in commonly detected cancer and fourth in cancer mortality. Recent progress in molecular modeling studies has led to significant success in drug discovery using structure and ligand-based methods. This study highlights aspects of the anticancer drug design. The structure and ligand-based drug design are discussed to investigate the molecular and quantum mechanics in anti-cancer drugs. Recent advances in anticancer agent identification driven by structural and molecular insights are presented. As a result, the recent advances in the field and the current scenario in drug designing of cancer drugs are discussed. This review provides information on how cancer drugs were formulated and identified using computational power by the drug discovery society.


2020 ◽  
Vol 20 (9) ◽  
pp. 779-787
Author(s):  
Kajal Ghosal ◽  
Christian Agatemor ◽  
Richard I. Han ◽  
Amy T. Ku ◽  
Sabu Thomas ◽  
...  

Chemotherapy employs anti-cancer drugs to stop the growth of cancerous cells, but one common obstacle to the success is the development of chemoresistance, which leads to failure of the previously effective anti-cancer drugs. Resistance arises from different mechanistic pathways, and in this critical review, we focus on the Fanconi Anemia (FA) pathway in chemoresistance. This pathway has yet to be intensively researched by mainstream cancer researchers. This review aims to inspire a new thrust toward the contribution of the FA pathway to drug resistance in cancer. We believe an indepth understanding of this pathway will open new frontiers to effectively treat drug-resistant cancer.


2006 ◽  
Vol 1 (3) ◽  
pp. 327-346 ◽  
Author(s):  
Stephen Ralph ◽  
Pauline Low ◽  
Langfeng Dong ◽  
Alfons Lawen ◽  
Jiri Neuzil

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