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Spindle assembly checkpoint targets

Jan G Ruppert, Kumiko Samejima, Melpomeni Platani, Oscar Molina, Hiroshi Kimura, A Arockia Jeyaprakash, Shinya Ohta, William C Earnshaw
The chromosomal passenger complex (CPC) is directed to centromeres during mitosis via binding to H3T3ph and Sgo1. Whether and how heterochromatin protein 1α (HP1α) influences CPC localisation and function during mitotic entry is less clear. Here, we alter HP1α dynamics by fusing it to a CENP-B DNA-binding domain. Tethered HP1 strongly recruits the CPC, destabilising kinetochore-microtubule interactions and activating the spindle assembly checkpoint. During mitotic exit, the tethered HP1 traps active CPC at centromeres...
February 21, 2018: EMBO Journal
Danielle Sitry-Shevah, Sharon Kaisari, Adar Teichner, Shirly Miniowitz-Shemtov, Avram Hershko
The mitotic checkpoint system ensures the fidelity of chromosome segregation in mitosis by preventing premature initiation of anaphase until correct bipolar attachment of chromosomes to the mitotic spindle is reached. It promotes the assembly of a mitotic checkpoint complex (MCC), composed of BubR1, Bub3, Cdc20, and Mad2, which inhibits the activity of the anaphase-promoting complex/cyclosome (APC/C) ubiquitin ligase. When the checkpoint is satisfied, anaphase is initiated by the disassembly of MCC. Previous studies indicated that the dissociation of APC/C-bound MCC requires ubiquitylation and suggested that the target of ubiquitylation is the Cdc20 component of MCC...
February 5, 2018: Proceedings of the National Academy of Sciences of the United States of America
Dang Wu, Lepeng Wang, Yanhong Yang, Jin Huang, Yuhua Hu, Yongwei Shu, Jingyu Zhang, Jing Zheng
Mitotic arrest deficient-like-1 (MAD2, also known as MAD2L1) is thought to be an important spindle assembly checkpoint protein, which ensures accurate chromosome segregation and is closely associated with poor prognosis in many cancer. As a MAD2 binding protein, p31comet counteracts the function of MAD2 and leads to mitotic checkpoint silence. In this study, we explore the function of MAD2-p31comet axis in malignant glioma cells. Our results showed that disruption of MAD2-p31comet axis by MAD2 knockdown or p31comet overexpression suppressed cell proliferation, survival and migration of glioma, indicating that MAD2-p31comet axis is required for maintaining glioma cells malignancy...
February 2, 2018: Biochemical and Biophysical Research Communications
Özge Saatci, Simone Borgoni, Özge Akbulut, Selvi Durmuş, Umar Raza, Erol Eyüpoğlu, Can Alkan, Aytekin Akyol, Özgür Kütük, Stefan Wiemann, Özgür Şahin
Trastuzumab-refractory, HER2 (human epidermal growth factor receptor 2)-positive breast cancer is commonly treated with trastuzumab emtansine (T-DM1), an antibody-drug conjugate of trastuzumab and the microtubule-targeting agent, DM1. However, drug response reduces greatly over time due to acquisition of resistance whose molecular mechanisms are mostly unknown. Here, we uncovered a novel mechanism of resistance against T-DM1 by combining whole transcriptome sequencing (RNA-Seq), proteomics and a targeted small interfering RNA (siRNA) sensitization screen for molecular level analysis of acquired and de novo T-DM1-resistant models of HER2-overexpressing breast cancer...
February 2, 2018: Oncogene
Kai Chen, Wenxiu Duan, Qianqian Han, Xuan Sun, Wenqian Li, Shuangyun Hu, Jiajia Wan, Jiang Wu, Yushu Ge, Dan Liu
Protein kinase monopolar spindle 1 plays an important role in spindle assembly checkpoint at the onset of mitosis. Over expression of MPS1 correlated with a wide range of human tumors makes it an attractive target for finding an effective and specific inhibitor. In this work, we performed molecular dynamics simulations of protein MPS1 itself as well as protein bound systems with the inhibitor and natural substrate based on crystal structures. The reported orally bioavailable 1h-pyrrolo [3,2-c] pyridine inhibitors of MPS1 maintained stable binding in the catalytic site while natural substrate ATP could not stay...
January 30, 2018: Journal of Biomolecular Structure & Dynamics
K L Thu, J Silvester, M J Elliott, W Ba-Alawi, M H Duncan, A C Elia, A S Mer, P Smirnov, Z Safikhani, B Haibe-Kains, T W Mak, D W Cescon
TTK protein kinase (TTK), also known as Monopolar spindle 1 (MPS1), is a key regulator of the spindle assembly checkpoint (SAC), which functions to maintain genomic integrity. TTK has emerged as a promising therapeutic target in human cancers, including triple-negative breast cancer (TNBC). Several TTK inhibitors (TTKis) are being evaluated in clinical trials, and an understanding of the mechanisms mediating TTKi sensitivity and resistance could inform the successful development of this class of agents. We evaluated the cellular effects of the potent clinical TTKi CFI-402257 in TNBC models...
January 29, 2018: Proceedings of the National Academy of Sciences of the United States of America
Joni M Seeling, Alexis A Farmer, Adam Mansfield, Hyuk Cho, Madhusudan Choudhary
Aurora kinases (AKs) are serine/threonine kinases that are essential for cell division. Humans have three AK genes: AKA, AKB, and AKC. AKA is required for centrosome assembly, centrosome separation, and bipolar spindle assembly, and its mutation leads to abnormal spindle morphology. AKB is required for the spindle checkpoint and proper cytokinesis, and mutations cause chromosome misalignment and cytokinesis failure. AKC is expressed in germ cells, and has a role in meiosis analogous to that of AKB in mitosis...
December 28, 2017: International Journal of Molecular Sciences
Yasuo Tsuda, Makoto Iimori, Yuichiro Nakashima, Ryota Nakanishi, Koji Ando, Kippei Ohgaki, Hiroyuki Kitao, Hiroshi Saeki, Eiji Oki, Yoshihiko Maehara
Tubulin-binding agents (TBAs) are designed to target microtubule (MT) dynamics, resulting in compromised mitotic spindles and an unsatisfied spindle assembly checkpoint. The activity of Aurora B kinase is indispensable for TBA-induced mitotic arrest, and its inhibition causes mitotic slippage and postmitotic endoreduplication. However, the precise phenomenon underlying mitotic slippage, which is caused by treatment with both Aurora B inhibitors and TBAs, and the cell fate after postmitotic slippage are not completely understood...
December 1, 2017: Scientific Reports
Claudio Alfieri, Suyang Zhang, David Barford
The anaphase promoting complex or cyclosome (APC/C) is a large multi-subunit E3 ubiquitin ligase that orchestrates cell cycle progression by mediating the degradation of important cell cycle regulators. During the two decades since its discovery, much has been learnt concerning its role in recognizing and ubiquitinating specific proteins in a cell-cycle-dependent manner, the mechanisms governing substrate specificity, the catalytic process of assembling polyubiquitin chains on its target proteins, and its regulation by phosphorylation and the spindle assembly checkpoint...
November 2017: Open Biology
Junbin Qian, Maria Adelaida García-Gimeno, Monique Beullens, Maria Giulia Manzione, Gerd Van der Hoeven, Juan Carlos Igual, Miguel Heredia, Pascual Sanz, Lendert Gelens, Mathieu Bollen
The spindle assembly checkpoint (SAC) generates a diffusible protein complex that prevents anaphase until all chromosomes are properly attached to spindle microtubules. A key step in SAC initiation is the recruitment of MAD1 to kinetochores, which is generally thought to be governed by the microtubule-kinetochore (MT-KT) attachment status. However, we demonstrate that the recruitment of MAD1 via BUB1, a conserved kinetochore receptor, is not affected by MT-KT interactions in human cells. Instead, BUB1:MAD1 interaction depends on BUB1 phosphorylation, which is controlled by a biochemical timer that integrates counteracting kinase and phosphatase effects on BUB1 into a pulse-generating incoherent feedforward loop...
November 16, 2017: Molecular Cell
Kurt Engeland
Activation of the p53 tumor suppressor can lead to cell cycle arrest. The key mechanism of p53-mediated arrest is transcriptional downregulation of many cell cycle genes. In recent years it has become evident that p53-dependent repression is controlled by the p53-p21-DREAM-E2F/CHR pathway (p53-DREAM pathway). DREAM is a transcriptional repressor that binds to E2F or CHR promoter sites. Gene regulation and deregulation by DREAM shares many mechanistic characteristics with the retinoblastoma pRB tumor suppressor that acts through E2F elements...
November 10, 2017: Cell Death and Differentiation
Silvia Martini, Tanya Soliman, Giuliana Gobbi, Prisco Mirandola, Cecilia Carubbi, Elena Masselli, Giulia Pozzi, Peter J Parker, Marco Vitale
To form a proper mitotic spindle, centrosomes must be duplicated and driven poleward in a timely and controlled fashion. Improper timing of centrosome separation and errors in mitotic spindle assembly may lead to chromosome instability, a hallmark of cancer. Protein Kinase C epsilon (PKCε) has recently emerged as a regulator of several cell cycle processes associated with the resolution of mitotic catenation during the metaphase-anaphase transition and in regulating the abscission checkpoint. However, an engagement of PKCε in earlier (pre)mitotic events has not been addressed...
October 11, 2017: Molecular Cancer Research: MCR
Pulari U Thangavelu, Cheng-Yu Lin, Srividya Vaidyanathan, Thu H M Nguyen, Eloise Dray, Pascal H G Duijf
During cell division, chromosome segregation is facilitated by the mitotic checkpoint, or spindle assembly checkpoint (SAC), which ensures correct kinetochore-microtubule attachments and prevents premature sister-chromatid separation. It is well established that misexpression of SAC components on the outer kinetochores promotes chromosome instability (CIN) and tumorigenesis. Here, we study the expression of CENP-I, a key component of the HIKM complex at the inner kinetochores, in breast cancer, including ductal, lobular, medullary and male breast carcinomas...
September 22, 2017: Oncotarget
Katharina Overlack, Tanja Bange, Florian Weissmann, Alex C Faesen, Stefano Maffini, Ivana Primorac, Franziska Müller, Jan-Michael Peters, Andrea Musacchio
The spindle assembly checkpoint (SAC) prevents premature sister chromatid separation during mitosis. Phosphorylation of unattached kinetochores by the Mps1 kinase promotes recruitment of SAC machinery that catalyzes assembly of the SAC effector mitotic checkpoint complex (MCC). The SAC protein Bub3 is a phospho-amino acid adaptor that forms structurally related stable complexes with functionally distinct paralogs named Bub1 and BubR1. A short motif ("loop") of Bub1, but not the equivalent loop of BubR1, enhances binding of Bub3 to kinetochore phospho-targets...
October 9, 2017: Current Biology: CB
Anna Ajduk, Bernhard Strauss, Jonathon Pines, Magdalena Zernicka-Goetz
The correct temporal regulation of mitosis underpins genomic stability because it ensures the alignment of chromosomes on the mitotic spindle that is required for their proper segregation to the two daughter cells. Crucially, sister chromatid separation must be delayed until all the chromosomes have attached to the spindle; this is achieved by the Spindle Assembly Checkpoint (SAC) that inhibits the Anaphase Promoting Complex/Cyclosome (APC/C) ubiquitin ligase. In many species the first embryonic M-phase is significantly prolonged compared to the subsequent divisions, but the reason behind this has remained unclear...
August 29, 2017: Scientific Reports
M Li, Z G Ren
Aurora A plays a key role in cellular mitosis. It is located in the centrosome and spindle, and is mainly involved in the processes of centrosome maturation and separation, bipolar spindle assembly, and the regulation of mitotic progression. Recent studies have suggested that Aurora A is involved in tumorigenesis and tumor development through multiple mechanisms. Overexpression of Aurora A could cause abnormal centrosome amplification, aneuploidy formation, and G2/M checkpoint defects, which result in chromosome instability and imbalance between cell division and apoptosis, and eventually leads to abnormal cell proliferation...
June 20, 2017: Zhonghua Gan Zang Bing za Zhi, Zhonghua Ganzangbing Zazhi, Chinese Journal of Hepatology
A Szymiczek, M Carbone, S Pastorino, A Napolitano, M Tanji, M Minaai, I Pagano, J M Mason, H I Pass, M R Bray, T W Mak, H Yang
Malignant mesothelioma (MM) is an aggressive malignancy, highly resistant to current medical and surgical therapies, whose tumor cells characteristically show a high level of aneuploidy and genomic instability. We tested our hypothesis that targeting chromosomal instability in MM would improve response to therapy. Thr/Tyr kinase (TTK)/monopolar spindle 1 kinase (Mps-1) is a kinase of the spindle assembly checkpoint that controls cell division and cell fate. CFI-402257 is a novel, selective inhibitor of Mps-1 with antineoplastic activity...
November 16, 2017: Oncogene
Pulari U Thangavelu, Cheng-Yu Lin, Srividya Vaidyanathan, Thu H M Nguyen, Eloise Dray, Pascal H G Duijf
During cell division, chromosome segregation is facilitated by the mitotic checkpoint, or spindle assembly checkpoint (SAC), which ensures correct kinetochore-microtubule attachments and prevents premature sister-chromatid separation. It is well established that misexpression of SAC components on the outer kinetochores promotes chromosome instability (CIN) and tumorigenesis. Here, we study the expression of CENP-I, a key component of the HIKM complex at the inner kinetochores, in breast cancer, including ductal, lobular, medullary and male breast carcinomas...
July 10, 2017: Oncotarget
Guido J R Zaman, Jeroen A D M de Roos, Marion A A Libouban, Martine B W Prinsen, Jos de Man, Rogier C Buijsman, Joost C M Uitdehaag
The spindle assembly checkpoint kinase TTK (Mps1) is a key regulator of chromosome segregation and is the subject of novel targeted therapy approaches by small-molecule inhibitors. Although the first TTK inhibitors have entered phase I dose escalating studies in combination with taxane chemotherapy, a patient stratification strategy is still missing. With the aim to identify a genomic biomarker to predict the response of tumor cells to TTK inhibitor therapy, we profiled a set of preclinical and clinical TTK inhibitors from different chemical series on a panel of 66 genetically characterized cell lines derived from different tumors (Oncolines)...
November 2017: Molecular Cancer Therapeutics
Jiamiao Zhang, Yan Jiang, Yu Zhao, Wanxue Wang, Yiran Xie, Huating Wang, Yihua Yang
Endometrial cancer is the most common gynecologic malignancy, about 80% of which is endometrial endometrioid carcinoma. Dysregulation of spindle assembly checkpoint plays a vital role in endometrial endometrioid carcinoma tumorigenesis and progression. The purpose of this study was to explore how tyrosine threonine kinase, a spindle assembly checkpoint-related protein, promotes the endometrial endometrioid carcinoma progression. We found that both messenger RNA and protein levels of tyrosine threonine kinase in endometrial endometrioid carcinoma tissues are higher than those in normal endometrial tissues, and its expression is associated with tumor stages...
July 2017: Tumour Biology: the Journal of the International Society for Oncodevelopmental Biology and Medicine
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