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Wang X, Li T, Xu J, Zhang F, Liu L, Wang T, Wang C, Ren H, Zhang Y. Distinct functions of microtubules and actin filaments in the transportation of the male germ unit in pollen. Nat Commun 2024; 15:5448. [PMID: 38937444 PMCID: PMC11211427 DOI: 10.1038/s41467-024-49323-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 06/02/2024] [Indexed: 06/29/2024] Open
Abstract
Flowering plants rely on the polarized growth of pollen tubes to deliver sperm cells (SCs) to the embryo sac for double fertilization. In pollen, the vegetative nucleus (VN) and two SCs form the male germ unit (MGU). However, the mechanism underlying directional transportation of MGU is not well understood. In this study, we provide the first full picture of the dynamic interplay among microtubules, actin filaments, and MGU during pollen germination and tube growth. Depolymerization of microtubules and inhibition of kinesin activity result in an increased velocity and magnified amplitude of VN's forward and backward movement. Pharmacological washout experiments further suggest that microtubules participate in coordinating the directional movement of MGU. In contrast, suppression of the actomyosin system leads to a reduced velocity of VN mobility but without a moving pattern change. Moreover, detailed observation shows that the direction and velocity of VN's movement are in close correlations with those of the actomyosin-driven cytoplasmic streaming surrounding VN. Therefore, we propose that while actomyosin-based cytoplasmic streaming influences on the oscillational movement of MGU, microtubules and kinesins avoid MGU drifting with the cytoplasmic streaming and act as the major regulator for fine-tuning the proper positioning and directional migration of MGU in pollen.
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Affiliation(s)
- Xiangfei Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Tonghui Li
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Jiuting Xu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Fanfan Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Lifang Liu
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Ting Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Chun Wang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China
| | - Haiyun Ren
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China.
- Center for Biological Science and Technology, Guangdong Zhuhai-Macao Joint Biotech Laboratory, Beijing Normal University, 519087, Zhuhai, China.
| | - Yi Zhang
- Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, 100875, Beijing, China.
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Ren J, Yao X, Yang M, Cheng S, Wu D, Xu K, Li R, Zhang H, Zhang D. Kinesin Family Member-18A (KIF18A) Promotes Cell Proliferation and Metastasis in Hepatocellular Carcinoma. Dig Dis Sci 2024; 69:1274-1286. [PMID: 38446308 PMCID: PMC11026273 DOI: 10.1007/s10620-024-08321-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 01/26/2024] [Indexed: 03/07/2024]
Abstract
BACKGROUND & AIMS Kinesin family member 18A (KIF18A) is notable for its aberrant expression across various cancer types and its pivotal role is driving cancer progression. In this study, we aim to investigate the intricate molecular mechanisms underlying the impact of KIF18A on the progression of HCC. METHODS Western blotting assays, a quantitative real-time PCR and immunohistochemical analyses were performed to quantitatively assess KIF18A expression in HCC tissues. We then performed genetic manipulations within HCC cells by silencing endogenous KIF18A using short hairpin RNA (shRNA) and introducing exogenous plasmids to overexpress KIF18A. We monitored cell progression, analyzed cell cycle and cell apoptosis and assessed cell migration and invasion both in vitro and in vivo. Moreover, we conducted RNA-sequencing to explore KIF18A-related signaling pathways utilizing Reactome and KEGG enrichment methods and validated these critical mediators in these pathways. RESULTS Analysis of the TCGA-LIHC database revealed pronounced overexpression of KIF18A in HCC tissues, the finding was subsequently confirmed through the analysis of clinical samples obtained from HCC patients. Notably, silencing KIF18A in cells led to an obvious inhibition of cell proliferation, migration and invasion in vitro. Furthermore, in subcutaneous and orthotopic xenograft models, suppression of KIF18A sgnificantly redudce tumor weight and the number of lung metastatic nodules. Mechanistically, KIF18A appears to facilitate cell proliferation by upregulating MAD2 and CDK1/CyclinB1 expression levels, with the activation of SMAD2/3 signaling contributing to KIF18A-driven metastasis. CONCLUSION Our study elucidates the molecular mechanism by which KIF18A mediates proliferation and metastasis in HCC cells, offering new insights into potential therapeutic targets.
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Affiliation(s)
- Jihua Ren
- The Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, 400016, China
| | - Xinyan Yao
- The Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, 400016, China
| | - Minli Yang
- The Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, 400016, China
| | - Shengtao Cheng
- The Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, 400016, China
| | - Daiqing Wu
- The Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, 400016, China
| | - Kexin Xu
- The Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, 400016, China
| | - Ranran Li
- The Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, 400016, China
| | - Han Zhang
- The Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, 400016, China
| | - Dapeng Zhang
- The Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, 400016, China.
- , Room 706, Chongyi Building, 1 Yixue Yuan Road, Yuzhong District, Chongqing, 400016, China.
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3
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Zhao K, Li X, Feng Y, Wang J, Yao W. The role of kinesin family members in hepatobiliary carcinomas: from bench to bedside. Biomark Res 2024; 12:30. [PMID: 38433242 PMCID: PMC10910842 DOI: 10.1186/s40364-024-00559-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 01/03/2024] [Indexed: 03/05/2024] Open
Abstract
As a major component of the digestive system malignancies, tumors originating from the hepatic and biliary ducts seriously endanger public health. The kinesins (KIFs) are molecular motors that enable the microtubule-dependent intracellular trafficking necessary for mitosis and meiosis. Normally, the stability of KIFs is essential to maintain cell proliferation and genetic homeostasis. However, aberrant KIFs activity may destroy this dynamic stability, leading to uncontrolled cell division and tumor initiation. In this work, we have made an integral summarization of the specific roles of KIFs in hepatocellular and biliary duct carcinogenesis, referring to aberrant signal transduction and the potential for prognostic evaluation. Additionally, current clinical applications of KIFs-targeted inhibitors have also been discussed, including their efficacy advantages, relationship with drug sensitivity or resistance, the feasibility of combination chemotherapy or other targeted agents, as well as the corresponding clinical trials. In conclusion, the abnormally activated KIFs participate in the regulation of tumor progression via a diverse range of mechanisms and are closely associated with tumor prognosis. Meanwhile, KIFs-aimed inhibitors also carry out a promising tumor-targeted therapeutic strategy that deserves to be further investigated in hepatobiliary carcinoma (HBC).
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Affiliation(s)
- Kai Zhao
- Department of Biliary and Pancreatic Surgery, Cancer Research Center Affiliated Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Xiangyu Li
- Department of Thoracic Surgery Affiliated Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Yunxiang Feng
- Department of Biliary and Pancreatic Surgery, Cancer Research Center Affiliated Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
| | - Jianming Wang
- Department of Biliary and Pancreatic Surgery, Cancer Research Center Affiliated Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China.
- Affiliated Tianyou Hospital, Wuhan University of Science & Technology, 430064, Wuhan, China.
| | - Wei Yao
- Department of Oncology Affiliated Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China.
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4
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Normandin K, Coulombe-Huntington J, St-Denis C, Bernard A, Bourouh M, Bertomeu T, Tyers M, Archambault V. Genetic enhancers of partial PLK1 inhibition reveal hypersensitivity to kinetochore perturbations. PLoS Genet 2023; 19:e1010903. [PMID: 37639469 PMCID: PMC10491399 DOI: 10.1371/journal.pgen.1010903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 09/08/2023] [Accepted: 08/06/2023] [Indexed: 08/31/2023] Open
Abstract
Polo-like kinase 1 (PLK1) is a serine/threonine kinase required for mitosis and cytokinesis. As cancer cells are often hypersensitive to partial PLK1 inactivation, chemical inhibitors of PLK1 have been developed and tested in clinical trials. However, these small molecule inhibitors alone are not completely effective. PLK1 promotes numerous molecular and cellular events in the cell division cycle and it is unclear which of these events most crucially depend on PLK1 activity. We used a CRISPR-based genome-wide screening strategy to identify genes whose inactivation enhances cell proliferation defects upon partial chemical inhibition of PLK1. Genes identified encode proteins that are functionally linked to PLK1 in multiple ways, most notably factors that promote centromere and kinetochore function. Loss of the kinesin KIF18A or the outer kinetochore protein SKA1 in PLK1-compromised cells resulted in mitotic defects, activation of the spindle assembly checkpoint and nuclear reassembly defects. We also show that PLK1-dependent CENP-A loading at centromeres is extremely sensitive to partial PLK1 inhibition. Our results suggest that partial inhibition of PLK1 compromises the integrity and function of the centromere/kinetochore complex, rendering cells hypersensitive to different kinetochore perturbations. We propose that KIF18A is a promising target for combinatorial therapies with PLK1 inhibitors.
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Affiliation(s)
- Karine Normandin
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | | | - Corinne St-Denis
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Alexandre Bernard
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Mohammed Bourouh
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Thierry Bertomeu
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
| | - Mike Tyers
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
- Département de médecine, Université de Montréal, Montréal, Canada
| | - Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, Canada
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5
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Tao BY, Liu YY, Liu HY, Zhang ZH, Guan YQ, Wang H, Shi Y, Zhang J. Prognostic Biomarker KIF18A and Its Correlations With Immune Infiltrates and Mitosis in Glioma. Front Genet 2022; 13:852049. [PMID: 35591854 PMCID: PMC9110815 DOI: 10.3389/fgene.2022.852049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 04/13/2022] [Indexed: 11/21/2022] Open
Abstract
Background: Glioma is globally recognised as one of the most frequently occurring primary malignant brain tumours, making the identification of glioma biomarkers critically significant. The protein KIF18A (Kinesin Family Member 18A) is a member of the kinesin superfamily of microtubule-associated molecular motors and has been shown to participate in cell cycle and mitotic metaphase and anaphase. This is the first investigation into the expression of KIF18A and its prognostic value, potential biological functions, and effects on the immune system and mitosis in glioma patients. Methods: Gene expression and clinicopathological analysis, enrichment analysis, and immune infiltration analysis were based on data obtained from The Cancer Genome Atlas (TCGA), with additional bioinformatics analyses performed. Statistical analysis was conducted in R software. Clinical samples were used to evaluate the expression of KIF18A via immunohistochemical staining. In addition, the expression level of KIF18A was validated on U87 cell line. Results: Our results highlighted that KIF18A plays a key role as an independent prognostic factor in patients with glioma. KIF18A was highly expressed in glioma tissues, and KIF18A expression was associated with age, World Health Organization grade, isocitrate dehydrogenase (IDH) status, 1p/19q codeletion, primary therapy outcome, and overall survival (OS). Enrichment analysis revealed that KIF18A is closely correlated with the cell cycle and mitosis. Single sample gene set enrichment analysis (ssGSEA) analysis revealed that KIF18A expression was related to the immune microenvironment. The increased expression of KIF18A in glioma was verified in clinical samples and U87 cell line. Conclusion: The identification of KIF18A as a new biomarker for glioma could help elucidate how changes in the glioma cell and immune microenvironment promote glioma malignancy. With further analysis, KIF18A may serve as an independent prognostic indicator for human glioma.
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Affiliation(s)
- Bing-Yan Tao
- Medical School of Chinese PLA, Beijing, China
- Department of Neurosurgery, The First Medical Centre, Chinese PLA General Hospital, Beijing, China
| | - Yu-Yang Liu
- Medical School of Chinese PLA, Beijing, China
- Department of Neurosurgery, The First Medical Centre, Chinese PLA General Hospital, Beijing, China
| | - Hong-Yu Liu
- Medical School of Chinese PLA, Beijing, China
- Department of Neurosurgery, The First Medical Centre, Chinese PLA General Hospital, Beijing, China
- Department of Neurosurgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, China
| | - Ze-Han Zhang
- Medical School of Chinese PLA, Beijing, China
- Department of Neurosurgery, The First Medical Centre, Chinese PLA General Hospital, Beijing, China
| | - Yun-Qian Guan
- Cell Therapy Center, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Hui Wang
- Department of Experimental Pathology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Ying Shi
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Jun Zhang
- Department of Neurosurgery, The First Medical Centre, Chinese PLA General Hospital, Beijing, China
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6
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Wang LB, Zhang XB, Liu J, Liu QJ. The Proliferation of Glioblastoma Is Contributed to Kinesin Family Member 18A and Medical Data Analysis of GBM. Front Genet 2022; 13:858882. [PMID: 35464837 PMCID: PMC9033168 DOI: 10.3389/fgene.2022.858882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 01/26/2022] [Indexed: 11/23/2022] Open
Abstract
Background: Glioblastoma (GBM) is widely known as a classical kind of malignant tumor originating in the brain with high morbidity and mortality. Targeted therapy has shown great promise in treating glioblastoma, but more promising targets, including effective therapeutic targets, remain to be identified. 18A (KIF18A) is a microtubule-based motor protein that is dysregulated and involved in the progression of multiple human cancers. However, the possible effects of KIF18A on GBM progression are still unclear. Methods: We performed DEG analysis, medical data analysis, and network analysis to identify critical genes affecting glioma progression. We also performed immunohistochemical analysis of the KIF18A levels in 94 patients with glioblastoma and the associated surrounding tissues. Patients were divided into two groups according to the high and low expression. Using a clinical analysis, we showed the potential associations between KIF18A expression and clinical characteristics of 94 GBM patients. We then investigated the effects of KIF18A on GBM cell proliferation by colony establishment, MTT, and immune blogging. The possible effect of KIF18A on GBM tumor growth was determined in mice. Results: We identified KIF18A as a potential gene affecting GBM progression. We further demonstrated that GBM tissues expressed KIF18A much higher, and its presentation was associated with recurrence in glioblastoma patients. We believe KIF18A promotes GBM cell proliferation. Conclusion: We demonstrated that KIF18A could be a promising target in treating GBM.
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Affiliation(s)
- Lei-Bo Wang
- Department of Neurosurgery, Tianjin Huanhu Hospital, Tianjin, China
| | - Xue-Bin Zhang
- Department of Pathology, Tianjin Huanhu Hospital, Tianjin, China
| | - Jun Liu
- Department of Neurosurgery, Tianjin Huanhu Hospital, Tianjin, China
| | - Qing-Jun Liu
- Department of Neurosurgery, Tianjin Huanhu Hospital, Tianjin, China
- *Correspondence: Qing-Jun Liu,
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7
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Tamayo NA, Bourbeau MP, Allen JR, Ashton KS, Chen JJ, Kaller MR, Nguyen TT, Nishimura N, Pettus LH, Walton M, Belmontes B, Moriguchi J, Chen K, McCarter JD, Hanestad K, Chung G, Ninniri MSS, Sun J, Poppe L, Spahr C, Hui J, Jia L, Wu T, Dahal UP, Edson KZ, Payton M. Targeting the Mitotic Kinesin KIF18A in Chromosomally Unstable Cancers: Hit Optimization Toward an In Vivo Chemical Probe. J Med Chem 2022; 65:4972-4990. [PMID: 35286090 DOI: 10.1021/acs.jmedchem.1c02030] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chromosomal instability (CIN) is a hallmark of cancer that results from errors in chromosome segregation during mitosis. Targeting of CIN-associated vulnerabilities is an emerging therapeutic strategy in drug development. KIF18A, a mitotic kinesin, has been shown to play a role in maintaining bipolar spindle integrity and promotes viability of CIN cancer cells. To explore the potential of KIF18A, a series of inhibitors was identified. Optimization of an initial hit led to the discovery of analogues that could be used as chemical probes to interrogate the role of KIF18A inhibition. Compounds 23 and 24 caused significant mitotic arrest in vivo, which was sustained for 24 h. This would be followed by cell death either in mitosis or in the subsequent interphase. Furthermore, photoaffinity labeling experiments reveal that this series of inhibitors binds at the interface of KIF18A and tubulin. This study represents the first disclosure of KIF18A inhibitors with in vivo activity.
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Affiliation(s)
- Nuria A Tamayo
- Medicinal Chemistry, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Matthew P Bourbeau
- Medicinal Chemistry, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Jennifer R Allen
- Medicinal Chemistry, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Kate S Ashton
- Medicinal Chemistry, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Jian Jeffrey Chen
- Medicinal Chemistry, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Matthew R Kaller
- Medicinal Chemistry, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Thomas T Nguyen
- Medicinal Chemistry, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Nobuko Nishimura
- Medicinal Chemistry, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Liping H Pettus
- Medicinal Chemistry, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Mary Walton
- Medicinal Chemistry, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Brian Belmontes
- Oncology Research, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Jodi Moriguchi
- Oncology Research, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Kui Chen
- Discovery Technologies, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - John D McCarter
- Discovery Technologies, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Kelly Hanestad
- Oncology Research, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Grace Chung
- Oncology Research, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Maria Stefania S Ninniri
- Oncology Research, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Jan Sun
- Oncology Research, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Leszek Poppe
- Discovery Attribute Sciences, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Chris Spahr
- Discovery Attribute Sciences, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - John Hui
- Discovery Attribute Sciences, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Lei Jia
- Computational & Data Sciences, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Tian Wu
- Pre-Pivotal Drug Product, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Upendra P Dahal
- Pharmacokinetics and Drug Metabolism, Amgen Research, 1120 Veterans Blvd., South San Francisco, California 94080, United States
| | - Katheryne Z Edson
- Pharmacokinetics and Drug Metabolism, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
| | - Marc Payton
- Oncology Research, Amgen Research, One Amgen Center Drive, Thousand Oaks, California 91320, United States
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8
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Iemura K, Yoshizaki Y, Kuniyasu K, Tanaka K. Attenuated Chromosome Oscillation as a Cause of Chromosomal Instability in Cancer Cells. Cancers (Basel) 2021; 13:cancers13184531. [PMID: 34572757 PMCID: PMC8470601 DOI: 10.3390/cancers13184531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 09/01/2021] [Accepted: 09/07/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Chromosomal instability (CIN), a condition in which chromosome missegregation occurs at high rates, is widely seen in cancer cells. Causes of CIN in cancer cells are not fully understood. A recent report suggests that chromosome oscillation, an iterative chromosome motion typically seen in metaphase around the spindle equator, is attenuated in cancer cells, and is associated with CIN. Chromosome oscillation promotes the correction of erroneous kinetochore-microtubule attachments through phosphorylation of Hec1, a kinetochore protein that binds to microtubules, by Aurora A kinase residing on the spindle. In this review, we focused on this unappreciated link between chromosome oscillation and CIN. Abstract Chromosomal instability (CIN) is commonly seen in cancer cells, and related to tumor progression and poor prognosis. Among the causes of CIN, insufficient correction of erroneous kinetochore (KT)-microtubule (MT) attachments plays pivotal roles in various situations. In this review, we focused on the previously unappreciated role of chromosome oscillation in the correction of erroneous KT-MT attachments, and its relevance to the etiology of CIN. First, we provided an overview of the error correction mechanisms for KT-MT attachments, especially the role of Aurora kinases in error correction by phosphorylating Hec1, which connects MT to KT. Next, we explained chromosome oscillation and its underlying mechanisms. Then we introduced how chromosome oscillation is involved in the error correction of KT-MT attachments, based on recent findings. Chromosome oscillation has been shown to promote Hec1 phosphorylation by Aurora A which localizes to the spindle. Finally, we discussed the link between attenuated chromosome oscillation and CIN in cancer cells. This link underscores the role of chromosome dynamics in mitotic fidelity, and the mutual relationship between defective chromosome dynamics and CIN in cancer cells that can be a target for cancer therapy.
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Cohen-Sharir Y, McFarland JM, Abdusamad M, Marquis C, Bernhard SV, Kazachkova M, Tang H, Ippolito MR, Laue K, Zerbib J, Malaby HLH, Jones A, Stautmeister LM, Bockaj I, Wardenaar R, Lyons N, Nagaraja A, Bass AJ, Spierings DCJ, Foijer F, Beroukhim R, Santaguida S, Golub TR, Stumpff J, Storchová Z, Ben-David U. Aneuploidy renders cancer cells vulnerable to mitotic checkpoint inhibition. Nature 2021; 590:486-491. [PMID: 33505028 PMCID: PMC8262644 DOI: 10.1038/s41586-020-03114-6] [Citation(s) in RCA: 112] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 11/19/2020] [Indexed: 01/30/2023]
Abstract
Selective targeting of aneuploid cells is an attractive strategy for cancer treatment1. However, it is unclear whether aneuploidy generates any clinically relevant vulnerabilities in cancer cells. Here we mapped the aneuploidy landscapes of about 1,000 human cancer cell lines, and analysed genetic and chemical perturbation screens2-9 to identify cellular vulnerabilities associated with aneuploidy. We found that aneuploid cancer cells show increased sensitivity to genetic perturbation of core components of the spindle assembly checkpoint (SAC), which ensures the proper segregation of chromosomes during mitosis10. Unexpectedly, we also found that aneuploid cancer cells were less sensitive than diploid cells to short-term exposure to multiple SAC inhibitors. Indeed, aneuploid cancer cells became increasingly sensitive to inhibition of SAC over time. Aneuploid cells exhibited aberrant spindle geometry and dynamics, and kept dividing when the SAC was inhibited, resulting in the accumulation of mitotic defects, and in unstable and less-fit karyotypes. Therefore, although aneuploid cancer cells could overcome inhibition of SAC more readily than diploid cells, their long-term proliferation was jeopardized. We identified a specific mitotic kinesin, KIF18A, whose activity was perturbed in aneuploid cancer cells. Aneuploid cancer cells were particularly vulnerable to depletion of KIF18A, and KIF18A overexpression restored their response to SAC inhibition. Our results identify a therapeutically relevant, synthetic lethal interaction between aneuploidy and the SAC.
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Affiliation(s)
- Yael Cohen-Sharir
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - James M McFarland
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Mai Abdusamad
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Carolyn Marquis
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Sara V Bernhard
- Department of Molecular Genetics, TU Kaiserlautern, Kaiserlautern, Germany
| | - Mariya Kazachkova
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Helen Tang
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Marica R Ippolito
- Department of Experimental Oncology at IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Kathrin Laue
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Johanna Zerbib
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Heidi L H Malaby
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Andrew Jones
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - Irena Bockaj
- European Research Institute for the Biology of Aging (ERIBA), University of Groningen, Groningen, The Netherlands
| | - René Wardenaar
- European Research Institute for the Biology of Aging (ERIBA), University of Groningen, Groningen, The Netherlands
| | - Nicholas Lyons
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ankur Nagaraja
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Dana Farber Cancer Institute, Boston, MA, USA
| | - Adam J Bass
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Dana Farber Cancer Institute, Boston, MA, USA
| | - Diana C J Spierings
- European Research Institute for the Biology of Aging (ERIBA), University of Groningen, Groningen, The Netherlands
| | - Floris Foijer
- European Research Institute for the Biology of Aging (ERIBA), University of Groningen, Groningen, The Netherlands
| | - Rameen Beroukhim
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Dana Farber Cancer Institute, Boston, MA, USA
| | - Stefano Santaguida
- Department of Experimental Oncology at IEO, European Institute of Oncology IRCCS, Milan, Italy
- Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy
| | - Todd R Golub
- Cancer Program, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Dana Farber Cancer Institute, Boston, MA, USA
| | - Jason Stumpff
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT, USA
| | - Zuzana Storchová
- Department of Molecular Genetics, TU Kaiserlautern, Kaiserlautern, Germany
| | - Uri Ben-David
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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10
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He X, Sun X, Shao Y. Network-based survival analysis to discover target genes for developing cancer immunotherapies and predicting patient survival. J Appl Stat 2021; 48:1352-1373. [PMID: 35444359 DOI: 10.1080/02664763.2020.1812543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recently, cancer immunotherapies have been life-savers, however, only a fraction of treated patients have durable responses. Consequently, statistical methods that enable the discovery of target genes for developing new treatments and predicting patient survival are of importance. This paper introduced a network-based survival analysis method and applied it to identify candidate genes as possible targets for developing new treatments. RNA-seq data from a mouse study was used to select differentially expressed genes, which were then translated to those in humans. We constructed a gene network and identified gene clusters using a training set of 310 human gliomas. Then we conducted gene set enrichment analysis to select the gene clusters with significant biological function. A penalized Cox model was built to identify a small set of candidate genes to predict survival. An independent set of 690 human glioma samples was used to evaluate predictive accuracy of the survival model. The areas under time-dependent ROC curves in both the training and validation sets are more than 90%, indicating strong association between selected genes and patient survival. Consequently, potential biomedical interventions targeting these genes might be able to alter their expressions and prolong patient survival.
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11
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Lin Y, Wei YL, She ZY. Kinesin-8 motors: regulation of microtubule dynamics and chromosome movements. Chromosoma 2020; 129:99-110. [PMID: 32417983 DOI: 10.1007/s00412-020-00736-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 02/01/2023]
Abstract
Microtubules are essential for intracellular transport, cell motility, spindle assembly, and chromosome segregation during cell division. Microtubule dynamics regulate the proper spindle organization and thus contribute to chromosome congression and segregation. Accumulating studies suggest that kinesin-8 motors are emerging regulators of microtubule dynamics and organizations. In this review, we provide an overview of the studies focused on kinesin-8 motors in cell division. We discuss the structures and molecular kinetics of kinesin-8 motors. We highlight the essential roles and mechanisms of kinesin-8 in the regulation of microtubule dynamics and spindle organization. We also shed light on the functions of kinesin-8 motors in chromosome movement and the spindle assembly checkpoint during the cell cycle.
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Affiliation(s)
- Yang Lin
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, Fujian, China.,Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, 350122, Fujian, China
| | - Ya-Lan Wei
- Fujian Obstetrics and Gynecology Hospital, Fuzhou, 350011, Fujian, China.,Medical Research Center, Fujian Maternity and Child Health Hospital, Affiliated Hospital of Fujian Medical University, Fuzhou, 350001, Fujian, China
| | - Zhen-Yu She
- Department of Cell Biology and Genetics, The School of Basic Medical Sciences, Fujian Medical University, Fuzhou, 350122, Fujian, China. .,Key Laboratory of Stem Cell Engineering and Regenerative Medicine, Fujian Province University, Fuzhou, 350122, Fujian, China.
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12
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Cho YB, Hong S, Kang KW, Kang JH, Lee SM, Seo YJ. Selective and ATP-competitive kinesin KIF18A inhibitor suppresses the replication of influenza A virus. J Cell Mol Med 2020; 24:5463-5475. [PMID: 32253833 PMCID: PMC7214149 DOI: 10.1111/jcmm.15200] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/13/2020] [Accepted: 03/06/2020] [Indexed: 12/22/2022] Open
Abstract
The influenza virus is one of the major public health threats. However, the development of efficient vaccines and therapeutic drugs to combat this virus is greatly limited by its frequent genetic mutations. Because of this, targeting the host factors required for influenza virus replication may be a more effective strategy for inhibiting a broader spectrum of variants. Here, we demonstrated that inhibition of a motor protein kinesin family member 18A (KIF18A) suppresses the replication of the influenza A virus (IAV). The expression of KIF18A in host cells was increased following IAV infection. Intriguingly, treatment with the selective and ATP‐competitive mitotic kinesin KIF18A inhibitor BTB‐1 substantially decreased the expression of viral RNAs and proteins, and the production of infectious viral particles, while overexpression of KIF18A enhanced the replication of IAV. Importantly, BTB‐1 treatment attenuated the activation of AKT, p38 MAPK, SAPK and Ran‐binding protein 3 (RanBP3), which led to the prevention of the nuclear export of viral ribonucleoprotein complexes. Notably, administration of BTB‐1 greatly improved the viability of IAV‐infected mice. Collectively, our results unveiled a beneficial role of KIF18A in IAV replication, and thus, KIF18A could be a potential therapeutic target for the control of IAV infection.
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Affiliation(s)
- Yong-Bin Cho
- Department of Life Science, Chung-Ang University, Seoul, South Korea
| | - Sungguan Hong
- Department of Chemistry, Chung-Ang University, Seoul, South Korea
| | - Kyung-Won Kang
- Division of Biotechnology, College of Environmental and Bioresources, Jeonbuk National University, Iksan, South Korea
| | - Ji-Hun Kang
- Department of Life Science, Chung-Ang University, Seoul, South Korea
| | - Sang-Myeong Lee
- Division of Biotechnology, College of Environmental and Bioresources, Jeonbuk National University, Iksan, South Korea
| | - Young-Jin Seo
- Department of Life Science, Chung-Ang University, Seoul, South Korea
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13
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Li X, Liu M, Zhang Z, Zhang L, Liang X, Sun L, Zhong D. High kinesin family member 18A expression correlates with poor prognosis in primary lung adenocarcinoma. Thorac Cancer 2019; 10:1103-1110. [PMID: 30907518 PMCID: PMC6500977 DOI: 10.1111/1759-7714.13051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/03/2019] [Accepted: 03/03/2019] [Indexed: 01/06/2023] Open
Abstract
Background Lung adenocarcinoma (LUAD) is the most prevalent pathological subtype of lung cancer. Kinesin family member 18A (KIF18A) plays an important role in tumorigenesis. Its roles in breast cancer, colorectal cancer, and other tumors have been demonstrated; however, studies of KIF18A in LUAD are limited. This study aimed to determine the role of KIF18A in LUAD progression and prognostic prediction. Methods KIF18A expression was examined in LUAD cells and tissues by immunohistochemistry and Western blotting. Cell proliferation assay was performed to study the role of KIF18A in LUAD cells. Correlations between KIF18A expression and clinicopathological features were analyzed. The role of KIF18A in LUAD prognosis was evaluated using data from The Cancer Genome Atlas (TCGA). Results KIF18A expression was increased in tumor cells and tissues. Downregulation of KIF18A expression resulted in the suppression of cancer cell proliferation in in vitro assays, and was particularly related to poor tumor differentiation, big tumor size, lymph node metastasis, and more advanced tumor stage. In the TCGA dataset, high KIF18A messenger RNA expression was associated with poor disease‐free and overall survival in patients with LUAD. In addition, multivariate analysis indicated that KIF18A is an independent prognostic factor of disease‐free and overall survival in LUAD. Conclusions Collectively, our results demonstrate that KIFl8A is highly expressed in LUAD. KIFl8A plays an important role in LUAD cell proliferation, but is a poor prognostic factor.
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Affiliation(s)
- Xiaoqing Li
- Department of Oncology, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Meirong Liu
- Department of Oncology, Tianjin Medical University General Hospital, Tianjin, China
| | - Zheng Zhang
- Tianjin Medical University Graduate School, Tianjin, China
| | - Linlin Zhang
- Department of Oncology, Tianjin Medical University General Hospital, Tianjin, China
| | - Xingmei Liang
- Department of Oncology, Tianjin Medical University General Hospital, Tianjin, China
| | - Linlin Sun
- Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Diansheng Zhong
- Department of Oncology, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China
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14
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Bugiel M, Schäffer E. Three-Dimensional Optical Tweezers Tracking Resolves Random Sideward Steps of the Kinesin-8 Kip3. Biophys J 2018; 115:1993-2002. [PMID: 30360926 DOI: 10.1016/j.bpj.2018.09.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/30/2018] [Accepted: 09/24/2018] [Indexed: 01/10/2023] Open
Abstract
The budding yeast kinesin-8 Kip3 is a highly processive motor protein that walks to the ends of cytoskeletal microtubules and shortens them in a collective manner. However, how exactly Kip3 reaches the microtubule end is unclear. Although rotations of microtubules in multimotored Kip3 gliding assays implied directed sideward switching between microtubule protofilaments, two-dimensional, single-molecule, optical-tweezers assays indicated that Kip3 randomly switched protofilaments. Here, we topographically suspended microtubules such that Kip3 motors could freely access the microtubules in three dimensions. Tracking single-motor-driven microspheres with a three-dimensional, zero-load, optical-tweezers-based force clamp showed that Kip3 switched protofilaments in discrete steps equally frequent in both directions. A statistical analysis confirmed the diffusive sideward motion of Kip3, consistent with the two-dimensional single-molecule results. Furthermore, we found that motors were in one of three states: either not switching protofilaments or switching between them with a slow or fast sideward-stepping rate. Interestingly, this sideward diffusion was limited to one turn, suggesting that motors could not cross the microtubule seam. The diffusive protofilament switching may enable Kip3 to efficiently bypass obstacles and reach the microtubule end for length regulation.
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Affiliation(s)
- Michael Bugiel
- Cellular Nanoscience, Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany
| | - Erik Schäffer
- Cellular Nanoscience, Center for Plant Molecular Biology (ZMBP), University of Tübingen, Tübingen, Germany.
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15
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Luo W, Liao M, Liao Y, Chen X, Huang C, Fan J, Liao W. The role of kinesin KIF18A in the invasion and metastasis of hepatocellular carcinoma. World J Surg Oncol 2018; 16:36. [PMID: 29466986 PMCID: PMC5822562 DOI: 10.1186/s12957-018-1342-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 02/14/2018] [Indexed: 12/23/2022] Open
Abstract
Background KIF18A is associated with a variety of tumours; however, the specific mechanism of action of KIF18A in hepatocellular carcinoma (HCC) remains unclear. In this study, in vitro and in vivo experiments were performed with the aim of exploring the potential function and molecular mechanism of kinesin KIF18A in the occurrence and development of HCC. Methods We detected the expression of KIF18A in tumour and adjacent tissues as well as cell proliferation, cell invasion and migration in hepatoma cells after silencing KIF18A. KIF18A-silenced hepatoma cells were subcutaneously injected into nude mice to verify the tumorigenicity of KIF18A. We also detected the expression of signal pathway-related proteins in hepatoma cells after KIF18A knockdown with the aim of exploring the association between KIF18A and related signalling pathways. Results The level of KIF18A protein was higher in liver cancer tissues than adjacent tissues. After silencing KIF18A in SMMC-7721 and HepG2 cells, cell growth was obviously inhibited; the migration and invasion abilities were significantly decreased and the in vivo tumour weight was decreased compared to the control group (0.201 ± 0.088 g vs 0.476 ± 0.126 g, p = 0.009). The expression of cell cycle-related protein (cyclin B1), invasion and metastasis-related proteins (MMP-7 and MMP-9) and Akt-related proteins in hepatoma cells was also decreased after knocking down KIF18A. Conclusions KIF18A may promote proliferation, invasion and metastasis of HCC cells by promoting the cell cycle signalling pathway as well as the Akt and MMP-7/MMP-9-related signalling pathways and may serve as a new target for the diagnosis and treatment of HCC.
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Affiliation(s)
- Weiwei Luo
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, 541001, Guangxi, People's Republic of China
| | - Minjun Liao
- Guangxi Medical University, Nanning, 530021, Guangxi, People's Republic of China
| | - Yan Liao
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, 541001, Guangxi, People's Republic of China.,Disease Prevention and Control Center of Guilin, Guilin, 541001, Guangxi, People's Republic of China
| | - Xinhuang Chen
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, 541001, Guangxi, People's Republic of China
| | - Chunyan Huang
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, 541001, Guangxi, People's Republic of China
| | - Jiyuan Fan
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, 541001, Guangxi, People's Republic of China
| | - Weijia Liao
- Laboratory of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Guilin Medical University, Guilin, 541001, Guangxi, People's Republic of China.
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16
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Abstract
Kinesins are a superfamily of ATP-dependent motors important for many microtubule-based functions, including multiple roles in mitosis. Small-molecule inhibitors of mitotic kinesins disrupt cell division and are being developed as antimitotic therapies. We investigated the molecular mechanism of the multitasking human mitotic kinesin Kif18A and its inhibition by the small molecule BTB-1. We used cryo-electron microscopy to visualize nucleotide-dependent conformational changes in microtubule-bound Kif18A, and the conformation of microtubule-bound, BTB-1-bound Kif18A. We calculated a putative BTB-1–binding site and validated this site experimentally to reveal the BTB-1 inhibition mechanism. Our work points to a general mechanism of kinesin inhibition, with wide implications for a targeted blockade of these motors in both dividing and interphase cells. Kinesin motors play diverse roles in mitosis and are targets for antimitotic drugs. The clinical significance of these motors emphasizes the importance of understanding the molecular basis of their function. Equally important, investigations into the modes of inhibition of these motors provide crucial information about their molecular mechanisms. Kif18A regulates spindle microtubules through its dual functionality, with microtubule-based stepping and regulation of microtubule dynamics. We investigated the mechanism of Kif18A and its inhibition by the small molecule BTB-1. The Kif18A motor domain drives ATP-dependent plus-end microtubule gliding, and undergoes conformational changes consistent with canonical mechanisms of plus-end–directed motility. The Kif18A motor domain also depolymerizes microtubule plus and minus ends. BTB-1 inhibits both of these microtubule-based Kif18A activities. A reconstruction of BTB-1–bound, microtubule-bound Kif18A, in combination with computational modeling, identified an allosteric BTB-1–binding site near loop5, where it blocks the ATP-dependent conformational changes that we characterized. Strikingly, BTB-1 binding is close to that of well-characterized Kif11 inhibitors that block tight microtubule binding, whereas BTB-1 traps Kif18A on the microtubule. Our work highlights a general mechanism of kinesin inhibition in which small-molecule binding near loop5 prevents a range of conformational changes, blocking motor function.
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