1
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Sun S, Zhou J, Liu P. Liquid-liquid phase separation of microtubule-binding proteins in the regulation of spindle assembly. Cell Prolif 2024:e13649. [PMID: 38736355 DOI: 10.1111/cpr.13649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/19/2024] [Accepted: 04/15/2024] [Indexed: 05/14/2024] Open
Abstract
Cell division is a highly regulated process essential for the accurate segregation of chromosomes. Central to this process is the assembly of a bipolar mitotic spindle, a highly dynamic microtubule (MT)-based structure responsible for chromosome movement. The nucleation and dynamics of MTs are intricately regulated by MT-binding proteins. Over the recent years, various MT-binding proteins have been reported to undergo liquid-liquid phase separation, forming either single- or multi-component condensates on MTs. Herein, we provide a comprehensive summary of the phase separation characteristics of these proteins. We underscore their critical roles in MT nucleation, spindle assembly and kinetochore-MT attachment during the cell division process. Furthermore, we discuss the current challenges and various remaining unsolved problems, highlights the ongoing research efforts aimed at a deeper understanding of the role of the phase separation process during spindle assembly and orientation. Our review aims to contribute to the collective knowledge in this area and stimulate further investigations that will enhance our comprehension of the intricate mechanisms governing cell division.
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Affiliation(s)
- Shuang Sun
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Institute of Biomedical Sciences, College of Life Sciences, Shandong Normal University, Jinan, China
| | - Jun Zhou
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Institute of Biomedical Sciences, College of Life Sciences, Shandong Normal University, Jinan, China
- State Key Laboratory of Medicinal Chemical Biology, Haihe Laboratory of Cell Ecosystem, College of Life Sciences, Nankai University, Tianjin, China
| | - Peiwei Liu
- Center for Cell Structure and Function, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Institute of Biomedical Sciences, College of Life Sciences, Shandong Normal University, Jinan, China
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2
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Islam A, Manjarrez-González JC, Song X, Gore T, Draviam VM. Search for chromosomal instability aiding variants reveal naturally occurring kinetochore gene variants that perturb chromosome segregation. iScience 2024; 27:109007. [PMID: 38361632 PMCID: PMC10867425 DOI: 10.1016/j.isci.2024.109007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/15/2023] [Accepted: 01/19/2024] [Indexed: 02/17/2024] Open
Abstract
Chromosomal instability (CIN) is a hallmark of cancers, and CIN-promoting mutations are not fully understood. Here, we report 141 chromosomal instability aiding variant (CIVa) candidates by assessing the prevalence of loss-of-function (LoF) variants in 135 chromosome segregation genes from over 150,000 humans. Unexpectedly, we observe both heterozygous and homozygous CIVa in Astrin and SKA3, two evolutionarily conserved kinetochore and microtubule-associated proteins essential for chromosome segregation. To stratify harmful versus harmless variants, we combine live-cell microscopy and controlled protein expression. We find the naturally occurring Astrin p.Q1012∗ variant is harmful as it fails to localize normally and induces chromosome misalignment and missegregation, in a dominant negative manner. In contrast, the Astrin p.L7Qfs∗21 variant generates a shorter isoform that localizes and functions normally, and the SKA3 p.Q70Kfs∗7 variant allows wild-type SKA complex localisation and function, revealing distinct resilience mechanisms that render these variants harmless. Thus, we present a scalable framework to predict and stratify naturally occurring CIVa, and provide insight into resilience mechanisms that compensate for naturally occurring CIVa.
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Affiliation(s)
- Asifa Islam
- School of Biological and Chemical Sciences, Queen Mary, University of London, London E1 4NS, UK
| | | | - Xinhong Song
- School of Biological and Chemical Sciences, Queen Mary, University of London, London E1 4NS, UK
| | - Trupti Gore
- School of Biological and Chemical Sciences, Queen Mary, University of London, London E1 4NS, UK
- London Interdisciplinary Doctoral Program, University College London, London, UK
| | - Viji M. Draviam
- School of Biological and Chemical Sciences, Queen Mary, University of London, London E1 4NS, UK
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3
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Zhang W, Xiao Y, Zhou Q, Zhu X, Zhang Y, Xiang Q, Wu S, Song X, Zhao J, Yuan R, Xiao B, Li L. KNSTRN Is a Prognostic Biomarker That Is Correlated with Immune Infiltration in Breast Cancer and Promotes Cell Cycle and Proliferation. Biochem Genet 2024:10.1007/s10528-023-10615-2. [PMID: 38198023 DOI: 10.1007/s10528-023-10615-2] [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: 09/25/2023] [Accepted: 11/29/2023] [Indexed: 01/11/2024]
Abstract
Kinetochore-localized astrin/SPAG5-binding protein (KNSTRN) promotes the progression of bladder cancer and lung adenocarcinoma. However, its expression and biological function in breast cancer remain largely unknown. Therefore, this study aimed to analyze KNSTRN expression, prognoses, correlation with immune infiltration, expression-associated genes, and regulated signaling pathways to characterize its role in regulating the cell cycle using both bioinformatics and in vitro functional experiments. Analyses of The Cancer Genome Atlas, Gene Expression Omnibus, TIMER, and The Human Protein Atlas databases revealed a significant upregulation of KNSTRN transcript and protein levels in breast cancer. Kaplan-Meier survival analyses demonstrated a significant association between high expression of KNSTRN and poor overall survival, relapse-free survival, post-progression survival, and distant metastases-free survival in patients with breast cancer. Furthermore, multivariate Cox regression analyses confirmed that KNSTRN is an independent prognostic factor for breast cancer. Immune infiltration analysis indicated a positive correlation between KNSTRN expression and T regulatory cell infiltration while showing a negative correlation with Tgd and natural killer cell infiltration. Gene set enrichment analysis along with single-cell transcriptome data analysis suggested that KNSTRN promoted cell cycle progression by regulating the expression of key cell cycle proteins. The overexpression and silencing of KNSTRN in vitro, respectively, promoted and inhibited the proliferation of breast cancer cells. The overexpression of KNSTRN enhanced the expression of key cell cycle regulators, including CDK4, CDK6, and cyclin D3, thereby accelerating the G1/S phase transition and leading to aberrant proliferation of breast cancer cells. In conclusion, our study demonstrates that KNSTRN functions as an oncogene in breast cancer by regulating immune response, promoting G1/S transition, and facilitating breast cancer cell proliferation. Moreover, KNSTRN has potential as a molecular biomarker for diagnostic and prognostic prediction in breast cancer.
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Affiliation(s)
- Wenwu Zhang
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, 511518, China
- Department of Laboratory Medicine, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, 215008, China
| | - Yuhan Xiao
- School of Public Health, Dali University, Dali, 671000, China
| | - Quan Zhou
- Department of Laboratory Medicine, General Hospital of Southern Theater Command of People's Liberation Army (PLA), Guangzhou, 510010, China
| | - Xin Zhu
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, 511518, China
| | - Yanxia Zhang
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, 511518, China
| | - Qin Xiang
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, 511518, China
| | - Shunhong Wu
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, 511518, China
| | - Xiaoyu Song
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, 511518, China
| | - Junxiu Zhao
- School of Public Health, Dali University, Dali, 671000, China
| | - Ruanfei Yuan
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, 511518, China
| | - Bin Xiao
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, 511518, China.
| | - Linhai Li
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People's Hospital, Qingyuan, 511518, China.
- Department of Laboratory Medicine, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Gusu School, Nanjing Medical University, Suzhou, 215008, China.
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4
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Jin L, Zhang X, Fan M, Li W, Zhang X. NamiRNA-mediated high expression of KNSTRN correlates with poor prognosis and immune infiltration in hepatocellular carcinoma. Contemp Oncol (Pozn) 2023; 27:163-175. [PMID: 38239867 PMCID: PMC10793618 DOI: 10.5114/wo.2023.133507] [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: 09/04/2023] [Accepted: 11/12/2023] [Indexed: 01/22/2024] Open
Abstract
Introduction Mutations of kinetochore-localized astrin/sperm-associated antigen 5 (KNSTRN) can interfere with chromatid cohesion, increase aneuploidy in tumours, and enhance tumourigenesis. However, the role of the KNSTRN-binding protein in hepatocellular carcinoma (HCC) remains unclear. Material and methods Using The Cancer Genome Atlas databases, we investigated the potential oncogenic functions of KNSTRN in HCC along with R and various computational tools. Results Detailed results revealed that elevated expression of KNSTRN was considerably associated with poor overall survival (HR = 1.48, 95% CI: 1.05-2.09, p = 0.027) and progress-free interval (HR = 1.41, 95% CI: 1.05-1.89, p = 0.021) in HCC. Gene ontology/Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis showed that KNSTRN is closely related to organelle fission, chromosomal region, tubulin binding, and cell cycle signalling pathway. TIMER database analysis showed the correlations between KNSTRN expression and tumour-infiltrating immune cells, biomarkers of immune cells, and immune checkpoint expression. Moreover, the KNSTRN level was significantly positively associated with immunosuppressive cells in the tumour microenvironment, including regulatory T-cells, myeloid-derived suppressor cells, and cancer-associated fibrocytes. Finally, a possible nuclear activating miRNA (NamiRNA)-enhancer network of hsa-miR-107, which activates the KNSTRN expression in liver hepatocellular carcinoma, was constructed by correlation analysis. Conclusions NamiRNA-mediated upregulation of KNSTRN correlated with poor prognosis and tumour immune infiltration in HCC. KNSTRN could serve as an effective biomarker for the diagnosis and prognosis of HCC and support the development of novel therapeutic strategies.
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Affiliation(s)
- Liang Jin
- Department of Hepatobiliary Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
| | - Xiaojing Zhang
- Department of Hepatobiliary Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
| | - Ming Fan
- Department of Hepatobiliary Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
| | - Weimin Li
- Department of Hepatobiliary Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
| | - Xuan Zhang
- Department of Hepatobiliary Surgery, Xijing Hospital, Air Force Medical University, Xi’an, Shaanxi, China
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5
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Ying Z, Wang K, Wu J, Wang M, Yang J, Wang X, Zhou G, Chen H, Xu H, Sze SCW, Gao F, Li C, Sha O. CCHCR1-astrin interaction promotes centriole duplication through recruitment of CEP72. BMC Biol 2022; 20:240. [PMID: 36280838 PMCID: PMC9590400 DOI: 10.1186/s12915-022-01437-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 10/14/2022] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND The centrosome is one of the most important non-membranous organelles regulating microtubule organization and progression of cell mitosis. The coiled-coil alpha-helical rod protein 1 (CCHCR1, also known as HCR) gene is considered to be a psoriasis susceptibility gene, and the protein is suggested to be localized to the P-bodies and centrosomes in mammalian cells. However, the exact cellular function of HCR and its potential regulatory role in the centrosomes remain unexplored. RESULTS We found that HCR interacts directly with astrin, a key factor in centrosome maturation and mitosis. Immunoprecipitation assays showed that the coiled-coil region present in the C-terminus of HCR and astrin respectively mediated the interaction between them. Astrin not only recruits HCR to the centrosome, but also protects HCR from ubiquitin-proteasome-mediated degradation. In addition, depletion of either HCR or astrin significantly reduced centrosome localization of CEP72 and subsequent MCPH proteins, including CEP152, CDK5RAP2, and CEP63. The absence of HCR also caused centriole duplication defects and mitotic errors, resulting in multipolar spindle formation, genomic instability, and DNA damage. CONCLUSION We conclude that HCR is localized and stabilized at the centrosome by directly binding to astrin. HCR are required for the centrosomal recruitment of MCPH proteins and centriolar duplication. Both HCR and astrin play key roles in keeping normal microtubule assembly and maintaining genomic stability.
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Affiliation(s)
- Zhenguang Ying
- Department of Anatomy, Histology and Developmental Biology, Shenzhen University Health Science Centre, Shenzhen, 518000, China
| | - Kaifang Wang
- Department of Anatomy, Histology and Developmental Biology, Shenzhen University Health Science Centre, Shenzhen, 518000, China
| | - Junfeng Wu
- Department of Anatomy, Histology and Developmental Biology, Shenzhen University Health Science Centre, Shenzhen, 518000, China
| | - Mingyu Wang
- Medical AI Laboratory, School of Biomedical Engineering, Shenzhen University Health Science Centre, Shenzhen, 518000, China
| | - Jing Yang
- Department of Anatomy, Histology and Developmental Biology, Shenzhen University Health Science Centre, Shenzhen, 518000, China
| | - Xia Wang
- Department of Anatomy, Histology and Developmental Biology, Shenzhen University Health Science Centre, Shenzhen, 518000, China
| | - Guowei Zhou
- Shenzhen University Health Science Centre, Shenzhen, 518000, China
| | - Haibin Chen
- Department of Histology and Embryology, Shantou University Medical College, Shantou, 515000, China
| | - Hongwu Xu
- Department of Neurosurgery, The First Affiliated Hospital of Shantou University Medical College, Shantou, 515000, China
- Department of Clinically Oriented Anatomy, Shantou University Medical College, Shantou, 515000, China
| | - Stephen Cho Wing Sze
- Department of Biology, Faculty of Science, Hong Kong Baptist University, Hongkong, 999077, China
- Golden Meditech Centre for NeuroRegeneration Sciences, Hong Kong Baptist University, Hongkong, 999077, China
| | - Feng Gao
- School of Dentistry, Shenzhen University Health Science Centre, Shenzhen, 518000, China
| | - Chunman Li
- Department of Anatomy, Shantou University Medical College, Shantou, 515000, China.
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou, 515000, China.
| | - Ou Sha
- Department of Anatomy, Histology and Developmental Biology, Shenzhen University Health Science Centre, Shenzhen, 518000, China.
- School of Dentistry, Shenzhen University Health Science Centre, Shenzhen, 518000, China.
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6
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Castrogiovanni C, Meraldi P. Cell division: The science friction of chromosome attachment. Curr Biol 2022; 32:R744-R746. [PMID: 35820385 DOI: 10.1016/j.cub.2022.05.045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
During mitosis, chromosomes must bind spindle microtubules via kinetochores in a stable yet dynamic manner to ensure rapid frictionless movements. A recent study identifies the first complex that specifically reduces friction in the kinetochore-microtubule interface to ensure efficient chromosome segregation.
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Affiliation(s)
- Cédric Castrogiovanni
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva 4, Switzerland; Translational Research Centre in Onco-hematology, Faculty of Medicine, University of Geneva, 1211 Geneva 4, Switzerland.
| | - Patrick Meraldi
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1211 Geneva 4, Switzerland; Translational Research Centre in Onco-hematology, Faculty of Medicine, University of Geneva, 1211 Geneva 4, Switzerland.
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7
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Rosas-Salvans M, Sutanto R, Suresh P, Dumont S. The Astrin-SKAP complex reduces friction at the kinetochore-microtubule interface. Curr Biol 2022; 32:2621-2631.e3. [PMID: 35580605 PMCID: PMC9295892 DOI: 10.1016/j.cub.2022.04.061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/17/2022] [Accepted: 04/21/2022] [Indexed: 10/18/2022]
Abstract
The kinetochore links chromosomes to spindle microtubules to drive chromosome segregation at cell division. While we know nearly all mammalian kinetochore proteins, how these give rise to the strong yet dynamic microtubule attachments required for function remains poorly understood. Here, we focus on the Astrin-SKAP complex, which localizes to bioriented kinetochores and is essential for chromosome segregation but whose mechanical role is unclear. Live imaging reveals that SKAP depletion dampens the movement and decreases the coordination of metaphase sister kinetochores and increases the tension between them. Using laser ablation to isolate kinetochores bound to polymerizing versus depolymerizing microtubules, we show that without SKAP, kinetochores move slower on both polymerizing and depolymerizing microtubules and that more force is needed to rescue microtubules to polymerize. Thus, in contrast to the previously described kinetochore proteins that increase the grip on microtubules under force, Astrin-SKAP reduces the grip, increasing attachment dynamics and force responsiveness and reducing friction. Together, our findings suggest a model where the Astrin-SKAP complex effectively "lubricates" correct, bioriented attachments to help preserve them.
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Affiliation(s)
- Miquel Rosas-Salvans
- Department of Bioengineering & Therapeutic Sciences, UCSF, 600 16th Street, San Francisco, CA 94158, USA.
| | - Renaldo Sutanto
- Department of Bioengineering & Therapeutic Sciences, UCSF, 600 16th Street, San Francisco, CA 94158, USA
| | - Pooja Suresh
- Department of Bioengineering & Therapeutic Sciences, UCSF, 600 16th Street, San Francisco, CA 94158, USA; Biophysics Graduate Program, UCSF, 600 16th Street, San Francisco, CA 94158, USA
| | - Sophie Dumont
- Department of Bioengineering & Therapeutic Sciences, UCSF, 600 16th Street, San Francisco, CA 94158, USA; Biophysics Graduate Program, UCSF, 600 16th Street, San Francisco, CA 94158, USA; Department of Biochemistry & Biophysics, UCSF, 600 16th Street, San Francisco, CA 94158, USA; Chan Zuckerberg Biohub, 499 Illinois Street, San Francisco, CA 94158, USA.
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8
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Dema A, van Haren J, Wittmann T. Optogenetic EB1 inactivation shortens metaphase spindles by disrupting cortical force-producing interactions with astral microtubules. Curr Biol 2022; 32:1197-1205.e4. [PMID: 35090591 PMCID: PMC8930524 DOI: 10.1016/j.cub.2022.01.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/09/2021] [Accepted: 01/07/2022] [Indexed: 10/19/2022]
Abstract
Chromosome segregation is accomplished by the mitotic spindle, a bipolar micromachine built primarily from microtubules. Different microtubule populations contribute to spindle function: kinetochore microtubules attach and transmit forces to chromosomes, antiparallel interpolar microtubules support spindle structure, and astral microtubules connect spindle poles to the cell cortex.1,2 In mammalian cells, end-binding (EB) proteins associate with all growing microtubule plus ends throughout the cell cycle and serve as adaptors for diverse +TIPs that control microtubule dynamics and interactions with other intracellular structures.3 Because binding of many +TIPs to EB1 and thus microtubule-end association is switched off by mitotic phosphorylation,4-6 the mitotic function of EBs remains poorly understood. To analyze how EB1 and associated +TIPs on different spindle microtubule populations contribute to mitotic spindle dynamics, we use a light-sensitive EB1 variant, π-EB1, that allows local, acute, and reversible inactivation of +TIP association with growing microtubule ends in live cells.7 We find that acute π-EB1 photoinactivation results in rapid and reversible metaphase spindle shortening and transient relaxation of tension across the central spindle. However, in contrast to interphase, π-EB1 photoinactivation does not inhibit microtubule growth in metaphase but instead increases astral microtubule length and number. Yet in the absence of EB1 activity, astral microtubules fail to engage the cortical dynein/dynactin machinery, and spindle poles move away from regions of π-EB1 photoinactivation. In conclusion, our optogenetic approach reveals mitotic EB1 functions that remain hidden in genetic experiments, likely due to compensatory molecular systems regulating vertebrate spindle dynamics.
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Affiliation(s)
- Alessandro Dema
- Department of Cell & Tissue Biology, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA
| | | | - Torsten Wittmann
- Department of Cell & Tissue Biology, University of California, San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143, USA.
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9
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Niazi Tabar A, Azizi H, Hashemi Karoii D, Skutella T. Testicular Localization and Potential Function of Vimentin Positive Cells during Spermatogonial Differentiation Stages. Animals (Basel) 2022; 12:ani12030268. [PMID: 35158592 PMCID: PMC8833806 DOI: 10.3390/ani12030268] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 12/18/2021] [Accepted: 01/03/2022] [Indexed: 01/27/2023] Open
Abstract
Simple Summary Spermatogonia stem cells (SSCs) in the testis are responsible for transmitting genetic information to subsequent generations. During the differentiation of SSCs, various cytoskeletons are involved in giving the cell shape and internal organization. One of the essential cytoskeletons that play functions in these spermatogenic processes is vimentin. This study examined the vimentin expression in vivo and in vitro by immunocytochemistry (ICC), immunohistochemistry (IMH), Fluidigm real-time polymerase chain reaction, and bioinformatics analysis. IMH analysis demonstrated that the high vimentin expression was localized in the middle and central testicular cords cells of seminiferous tubules and low expression in the basal region under in vivo conditions. To evaluate the expression of vimentin in vitro, we first isolated SSCs and then cultured cells from the testis. Our results showed that vimentin plays important roles in the differentiation of testicular germ cells. Abstract Vimentin is a type of intermediate filament (IF) and one of the first filaments expressed in spermatogenesis. Vimentin plays numerous roles, consisting of the determination of cell shape, differentiation, cell motility, the maintenance of cell junctions, intracellular trafficking, and assisting in keeping normal differentiating germ cell morphology. This study investigated the vimentin expression in two populations of undifferentiated and differentiated spermatogonia. We examined vimentin expression in vivo and in vitro by immunocytochemistry (ICC), immunohistochemistry (IMH), and Fluidigm real-time polymerase chain reaction. IMH data showed that the high vimentin expression was localized in the middle of seminiferous tubules, and low expression was in the basal membrane. ICC analysis of the colonies by isolated differentiated spermatogonia indicated the positive expression for the vimentin antibody, but vimentin’s expression level in the undifferentiated population was negative under in vitro conditions. Fluidigm real-time PCR analysis showed significant vimentin expression in differentiated spermatogonia compared to undifferentiated spermatogonia (p < 0.05). Our results showed that vimentin is upregulated in the differentiation stages of spermatogenesis, proving that vimentin is an intermediate filament with crucial roles in the differentiation stages of testicular germ cells. These results support the advanced investigations of the spermatogenic process, both in vitro and in vivo.
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Affiliation(s)
- Amirreza Niazi Tabar
- Faculty of Biotechnology, Amol University of Special Modern Technologies, Amol 4616849767, Iran; (A.N.T.); (D.H.K.)
| | - Hossein Azizi
- Faculty of Biotechnology, Amol University of Special Modern Technologies, Amol 4616849767, Iran; (A.N.T.); (D.H.K.)
- Correspondence:
| | - Danial Hashemi Karoii
- Faculty of Biotechnology, Amol University of Special Modern Technologies, Amol 4616849767, Iran; (A.N.T.); (D.H.K.)
| | - Thomas Skutella
- Institute for Anatomy and Cell Biology, Medical Faculty, University of Heidelberg, Im Neuenheimer Feld 307, 69120 Heidelberg, Germany;
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10
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Song X, Conti D, Shrestha RL, Braun D, Draviam VM. Counteraction between Astrin-PP1 and Cyclin-B-CDK1 pathways protects chromosome-microtubule attachments independent of biorientation. Nat Commun 2021; 12:7010. [PMID: 34853300 PMCID: PMC8636589 DOI: 10.1038/s41467-021-27131-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 11/02/2021] [Indexed: 02/08/2023] Open
Abstract
Defects in chromosome-microtubule attachment can cause chromosomal instability (CIN), frequently associated with infertility and aggressive cancers. Chromosome-microtubule attachment is mediated by a large macromolecular structure, the kinetochore. Sister kinetochores of each chromosome are pulled by microtubules from opposing spindle-poles, a state called biorientation which prevents chromosome missegregation. Kinetochore-microtubule attachments that lack the opposing-pull are detached by Aurora-B/Ipl1. It is unclear how mono-oriented attachments that precede biorientation are spared despite the lack of opposing-pull. Using an RNAi-screen, we uncover a unique role for the Astrin-SKAP complex in protecting mono-oriented attachments. We provide evidence of domains in the microtubule-end associated protein that sense changes specific to end-on kinetochore-microtubule attachments and assemble an outer-kinetochore crescent to stabilise attachments. We find that Astrin-PP1 and Cyclin-B-CDK1 pathways counteract each other to preserve mono-oriented attachments. Thus, CIN prevention pathways are not only surveying attachment defects but also actively recognising and stabilising mature attachments independent of biorientation. Chromosome instability frequently occurs due to issues with chromosome-microtubule attachments. Here the authors show that the Astrin-PP1 and Cyclin-B-CDK1 pathways counteract each other to protect chromosome-microtubule attachments independent of biorientation.
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Affiliation(s)
- Xinhong Song
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, E1 4NS, UK
| | - Duccio Conti
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, E1 4NS, UK.,Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227, Dortmund, Germany
| | - Roshan L Shrestha
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK.,Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Dominique Braun
- Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK
| | - Viji M Draviam
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, E1 4NS, UK. .,Department of Genetics, University of Cambridge, Cambridge, CB2 3EH, UK.
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11
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The Aurora B gradient sustains kinetochore stability in anaphase. Cell Rep 2021; 37:109818. [PMID: 34758321 PMCID: PMC8595645 DOI: 10.1016/j.celrep.2021.109818] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/20/2021] [Accepted: 09/17/2021] [Indexed: 12/02/2022] Open
Abstract
Kinetochores assemble on chromosomes in mitosis to allow microtubules to attach and bring about accurate chromosome segregation. The kinases Cyclin B-Cdk1 and Aurora B are crucial for the formation of stable kinetochores. However, the activity of these two kinases appears to decline dramatically at centromeres during anaphase onset, precisely when microtubule attachments are required to move chromosomes toward opposite poles of the dividing cell. We find that, although Aurora B leaves centromeres at anaphase, a gradient of Aurora B activity centered on the central spindle is still able to phosphorylate kinetochore substrates such as Dsn1 to modulate kinetochore stability in anaphase and to regulate kinetochore disassembly as cells enter telophase. We provide a model to explain how Aurora B co-operates with Cyclin B-Cdk1 to maintain kinetochore function in anaphase. Central spindle Aurora B targets kinetochore substrates in anaphase Phosphorylation of Dsn1 by Aurora B stabilizes kinetochores in anaphase Dsn1 phosphorylation modulates chromosome movements in anaphase
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12
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Garcia YA, Velasquez EF, Gao LW, Gholkar AA, Clutario KM, Cheung K, Williams-Hamilton T, Whitelegge JP, Torres JZ. Mapping Proximity Associations of Core Spindle Assembly Checkpoint Proteins. J Proteome Res 2021; 20:3414-3427. [PMID: 34087075 PMCID: PMC8256817 DOI: 10.1021/acs.jproteome.0c00941] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Indexed: 12/25/2022]
Abstract
The spindle assembly checkpoint (SAC) is critical for sensing defective microtubule-kinetochore attachments and tension across the kinetochore and functions to arrest cells in prometaphase to allow time to repair any errors before proceeding into anaphase. Dysregulation of the SAC leads to chromosome segregation errors that have been linked to human diseases like cancer. Although much has been learned about the composition of the SAC and the factors that regulate its activity, the proximity associations of core SAC components have not been explored in a systematic manner. Here, we have taken a BioID2-proximity-labeling proteomic approach to define the proximity protein environment for each of the five core SAC proteins BUB1, BUB3, BUBR1, MAD1L1, and MAD2L1 in mitotic-enriched populations of cells where the SAC is active. These five protein association maps were integrated to generate a SAC proximity protein network that contains multiple layers of information related to core SAC protein complexes, protein-protein interactions, and proximity associations. Our analysis validated many known SAC complexes and protein-protein interactions. Additionally, it uncovered new protein associations, including the ELYS-MAD1L1 interaction that we have validated, which lend insight into the functioning of core SAC proteins and highlight future areas of investigation to better understand the SAC.
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Affiliation(s)
- Yenni A. Garcia
- Department of Chemistry and Biochemistry,
University of California, Los Angeles, California 90095,
United States
| | - Erick F. Velasquez
- Department of Chemistry and Biochemistry,
University of California, Los Angeles, California 90095,
United States
| | - Lucy W. Gao
- Pasarow Mass Spectrometry Laboratory, The Jane and
Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of
Medicine, University of California, Los Angeles, California
90095, United States
| | - Ankur A. Gholkar
- Department of Chemistry and Biochemistry,
University of California, Los Angeles, California 90095,
United States
| | - Kevin M. Clutario
- Department of Chemistry and Biochemistry,
University of California, Los Angeles, California 90095,
United States
| | - Keith Cheung
- Department of Chemistry and Biochemistry,
University of California, Los Angeles, California 90095,
United States
| | - Taylor Williams-Hamilton
- Department of Chemistry and Biochemistry,
University of California, Los Angeles, California 90095,
United States
| | - Julian P. Whitelegge
- Pasarow Mass Spectrometry Laboratory, The Jane and
Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of
Medicine, University of California, Los Angeles, California
90095, United States
- Molecular Biology Institute, University of
California, Los Angeles, California 90095, United
States
- Jonsson Comprehensive Cancer Center,
University of California, Los Angeles, California 90095,
United States
| | - Jorge Z. Torres
- Department of Chemistry and Biochemistry,
University of California, Los Angeles, California 90095,
United States
- Molecular Biology Institute, University of
California, Los Angeles, California 90095, United
States
- Jonsson Comprehensive Cancer Center,
University of California, Los Angeles, California 90095,
United States
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13
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Navarro AP, Cheeseman IM. Kinetochore assembly throughout the cell cycle. Semin Cell Dev Biol 2021; 117:62-74. [PMID: 33753005 DOI: 10.1016/j.semcdb.2021.03.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/12/2021] [Accepted: 03/13/2021] [Indexed: 11/29/2022]
Abstract
The kinetochore plays an essential role in facilitating chromosome segregation during cell division. This massive protein complex assembles onto the centromere of chromosomes and enables their attachment to spindle microtubules during mitosis. The kinetochore also functions as a signaling hub to regulate cell cycle progression, and is crucial to ensuring the fidelity of chromosome segregation. Despite the fact that kinetochores are large and robust molecular assemblies, they are also highly dynamic structures that undergo structural and organizational changes throughout the cell cycle. This review will highlight our current understanding of kinetochore structure and function, focusing on the dynamic processes that underlie kinetochore assembly.
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Affiliation(s)
- Alexandra P Navarro
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Iain M Cheeseman
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
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14
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Xiong Y, Ju L, Yuan L, Chen L, Wang G, Xu H, Peng T, Luo Y, Xiao Y, Wang X. KNSTRN promotes tumorigenesis and gemcitabine resistance by activating AKT in bladder cancer. Oncogene 2021; 40:1595-1608. [PMID: 33452459 DOI: 10.1038/s41388-020-01634-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 01/29/2023]
Abstract
KNSTRN is a component of the mitotic spindle, which was rarely investigated in tumorigenesis. AKT plays an essential role in tumorigenesis by modulating the phosphorylation of various substrates. The activation of AKT is regulated by PTEN and PIP3. Here, we prove KNSTRN is positively correlated with malignancy of bladder cancer and KNSTRN activates AKT phosphorylation at Thr308 and Ser473. More importantly, our study reveals that both KNSTRN and PTEN interact with PH domain of AKT at cell membrane. The amount of KNSTRN interacted with AKT is negatively related to PTEN. Furthermore, PIP3 pull-down assay proves that KNSTRN promoted AKT movement to PIP3. These data suggest KNSTRN may activate AKT phosphorylation by promoting AKT movement to PIP3 and alleviating PTEN suppression. Based on the activation of AKT phosphorylation, our study demonstrates that KNSTRN promotes bladder cancer metastasis and gemcitabine resistance in vitro and in vivo. Meanwhile, the effect of KNSTRN on tumorigenesis and gemcitabine resistance could be restored by AKT specific inhibitor MK2206 or AKT overexpression. In conclusion, we identify an oncogene KNSTRN that promotes tumorigenesis and gemcitabine resistance by activating AKT phosphorylation and may serve as a therapeutic target in bladder cancer.
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Affiliation(s)
- Yaoyi Xiong
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Lingao Ju
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China.,Human Genetic Resource Preservation Center of Hubei Province, Wuhan, China.,Research Center of Wuhan for Infectious Diseases and Cancer, Chinese Academy of Medical Sciences, Wuhan, China
| | - Lushun Yuan
- Division of Nephrology, Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Liang Chen
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China.,Signal Transduction Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, NC, USA
| | - Gang Wang
- Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China.,Human Genetic Resource Preservation Center of Hubei Province, Wuhan, China.,Research Center of Wuhan for Infectious Diseases and Cancer, Chinese Academy of Medical Sciences, Wuhan, China
| | - Huimin Xu
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Tianchen Peng
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yongwen Luo
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Yu Xiao
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China. .,Department of Biological Repositories, Zhongnan Hospital of Wuhan University, Wuhan, China. .,Human Genetic Resource Preservation Center of Hubei Province, Wuhan, China. .,Research Center of Wuhan for Infectious Diseases and Cancer, Chinese Academy of Medical Sciences, Wuhan, China. .,Laboratory of Precision Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China.
| | - Xinghuan Wang
- Department of Urology, Zhongnan Hospital of Wuhan University, Wuhan, China. .,Research Center of Wuhan for Infectious Diseases and Cancer, Chinese Academy of Medical Sciences, Wuhan, China. .,Medical Research Institute, Wuhan University, Wuhan, China.
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15
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Geraghty Z, Barnard C, Uluocak P, Gruneberg U. The association of Plk1 with the astrin-kinastrin complex promotes formation and maintenance of a metaphase plate. J Cell Sci 2021; 134:jcs251025. [PMID: 33288550 PMCID: PMC7803464 DOI: 10.1242/jcs.251025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 11/30/2020] [Indexed: 11/20/2022] Open
Abstract
Errors in mitotic chromosome segregation can lead to DNA damage and aneuploidy, both hallmarks of cancer. To achieve synchronous error-free segregation, mitotic chromosomes must align at the metaphase plate with stable amphitelic attachments to microtubules emanating from opposing spindle poles. The astrin-kinastrin (astrin is also known as SPAG5 and kinastrin as SKAP) complex, also containing DYNLL1 and MYCBP, is a spindle and kinetochore protein complex with important roles in bipolar spindle formation, chromosome alignment and microtubule-kinetochore attachment. However, the molecular mechanisms by which astrin-kinastrin fulfils these diverse roles are not fully understood. Here, we characterise a direct interaction between astrin and the mitotic kinase Plk1. We identify the Plk1-binding site on astrin as well as four Plk1 phosphorylation sites on astrin. Regulation of astrin by Plk1 is dispensable for bipolar spindle formation and bulk chromosome congression, but promotes stable microtubule-kinetochore attachments and metaphase plate maintenance. It is known that Plk1 activity is required for effective microtubule-kinetochore attachment formation, and we suggest that astrin phosphorylation by Plk1 contributes to this process.
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Affiliation(s)
- Zoë Geraghty
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Christina Barnard
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Pelin Uluocak
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Ulrike Gruneberg
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
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16
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Kajio N, Takeshita M, Suzuki K, Kaneda Y, Yamane H, Ikeura K, Sato H, Kato S, Shimizu H, Tsunoda K, Takeuchi T. Anti-centromere antibodies target centromere-kinetochore macrocomplex: a comprehensive autoantigen profiling. Ann Rheum Dis 2020; 80:651-659. [PMID: 33208344 PMCID: PMC8053351 DOI: 10.1136/annrheumdis-2020-218881] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 12/01/2022]
Abstract
Objectives Anti-centromere antibodies (ACAs) are detected in patients with various autoimmune diseases such as Sjögren’s syndrome (SS), systemic sclerosis (SSc) and primary biliary cholangitis (PBC). However, the targeted antigens of ACAs are not fully elucidated despite the accumulating understanding of the molecular structure of the centromere. The aim of this study was to comprehensively reveal the autoantigenicity of centromere proteins. Methods A centromere antigen library including 16 principal subcomplexes composed of 41 centromere proteins was constructed. Centromere protein/complex binding beads were used to detect serum ACAs in patients with SS, SSc and PBC. ACA-secreting cells in salivary glands obtained from patients with SS were detected with green fluorescent protein-fusion centromere antigens and semiquantified with confocal microscopy. Results A total of 241 individuals with SS, SSc or PBC and healthy controls were recruited for serum ACA profiling. A broad spectrum of serum autoantibodies was observed, and some of them had comparative frequency as anti-CENP-B antibody, which is the known major ACA. The prevalence of each antibody was shared across the three diseases. Immunostaining of SS salivary glands showed the accumulation of antibody-secreting cells (ASCs) specific for kinetochore, which is a part of the centromere, whereas little reactivity against CENP-B was seen. Conclusions We demonstrated that serum autoantibodies target the centromere–kinetochore macrocomplex in patients with SS, SSc and PBC. The specificity of ASCs in SS salivary glands suggests kinetochore complex-driven autoantibody selection, providing insight into the underlying mechanism of ACA acquisition.
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Affiliation(s)
- Nobuhiko Kajio
- Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Masaru Takeshita
- Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Katsuya Suzuki
- Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Yukari Kaneda
- Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Humitsugu Yamane
- Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Kazuhiro Ikeura
- Division of Oral and Maxillofacial Surgery, Department of Dentistry and Oral Surgery, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Hidekazu Sato
- Division of Oral and Maxillofacial Surgery, Department of Dentistry and Oral Surgery, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Shin Kato
- Division of Oral and Maxillofacial Surgery, Department of Dentistry and Oral Surgery, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Hiroyuki Shimizu
- Division of Oral and Maxillofacial Surgery, Department of Dentistry and Oral Surgery, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Kazuyuki Tsunoda
- Division of Oral and Maxillofacial Surgery, Department of Dentistry and Oral Surgery, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Tsutomu Takeuchi
- Division of Rheumatology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
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17
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Ying Z, Yang J, Li W, Wang X, Zhu Z, Jiang W, Li C, Sha O. Astrin: A Key Player in Mitosis and Cancer. Front Cell Dev Biol 2020; 8:866. [PMID: 32984344 PMCID: PMC7484939 DOI: 10.3389/fcell.2020.00866] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/11/2020] [Indexed: 12/04/2022] Open
Abstract
Astrin, which is a spindle-associated protein, was found to be closely related to mitotic spindle formation and maintenance. It interacts with other spindle-related proteins to play a key role in maintaining the attachment of the kinetochore-microtubule and integrity of centrosomes and promoting the centriole duplication. In addition, Astrin was quite recently found to be abnormally highly expressed in a variety of cancers. Astrin promotes the development of cancer by participating in various molecular pathways and is considered as a potential prognostic and survival predictor.
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Affiliation(s)
- Zhenguang Ying
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science Centre, Shenzhen, China
| | - Jing Yang
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science Centre, Shenzhen, China
| | - Wei Li
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science Centre, Shenzhen, China
| | - Xia Wang
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science Centre, Shenzhen, China
| | - Zeyao Zhu
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science Centre, Shenzhen, China
| | - Weipeng Jiang
- School of Dentistry, Shenzhen University Health Science Centre, Shenzhen, China
| | - Chunman Li
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science Centre, Shenzhen, China
| | - Ou Sha
- Department of Anatomy, Histology and Developmental Biology, School of Basic Medical Sciences, Shenzhen University Health Science Centre, Shenzhen, China.,School of Dentistry, Shenzhen University Health Science Centre, Shenzhen, China
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18
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Kinetochore-microtubule coupling mechanisms mediated by the Ska1 complex and Cdt1. Essays Biochem 2020; 64:337-347. [PMID: 32844209 DOI: 10.1042/ebc20190075] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/03/2020] [Accepted: 08/06/2020] [Indexed: 11/17/2022]
Abstract
The faithful segregation of duplicated sister chromatids rely on the remarkable ability of kinetochores to sustain stable load bearing attachments with the dynamic plus ends of kinetochore-microtubules (kMTs). The outer layer of the kinetochore recruits several motor and non-motor microtubule-associated proteins (MAPs) that help the kinetochores establish and maintain a load bearing dynamic attachment with kMTs. The primary kMT-binding protein, the Ndc80 complex (Ndc80c), which is highly conserved among diverse organisms from yeast to humans, performs this essential function with assistance from other MAPs. These MAPs are not an integral part of the kinetochore, but they localize to the kinetochore periodically throughout mitosis and regulate the strength of the kinetochore microtubule attachments. Here, we attempt to summarize the recent advances that have been made toward furthering our understanding of this co-operation between the Ndc80c and these MAPs, focusing on the spindle and kinetochore-associated 1 (Ska1) complex (Ska1c) and Cdc10-dependent transcript 1 (Cdt1) in humans.
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19
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Kixmoeller K, Allu PK, Black BE. The centromere comes into focus: from CENP-A nucleosomes to kinetochore connections with the spindle. Open Biol 2020; 10:200051. [PMID: 32516549 PMCID: PMC7333888 DOI: 10.1098/rsob.200051] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Eukaryotic chromosome segregation relies upon specific connections from DNA to the microtubule-based spindle that forms at cell division. The chromosomal locus that directs this process is the centromere, where a structure called the kinetochore forms upon entry into mitosis. Recent crystallography and single-particle electron microscopy have provided unprecedented high-resolution views of the molecular complexes involved in this process. The centromere is epigenetically specified by nucleosomes harbouring a histone H3 variant, CENP-A, and we review recent progress on how it differentiates centromeric chromatin from the rest of the chromosome, the biochemical pathway that mediates its assembly and how two non-histone components of the centromere specifically recognize CENP-A nucleosomes. The core centromeric nucleosome complex (CCNC) is required to recruit a 16-subunit complex termed the constitutive centromere associated network (CCAN), and we highlight recent structures reported of the budding yeast CCAN. Finally, the structures of multiple modular sub-complexes of the kinetochore have been solved at near-atomic resolution, providing insight into how connections are made to the CCAN on one end and to the spindle microtubules on the other. One can now build molecular models from the DNA through to the physical connections to microtubules.
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Affiliation(s)
- Kathryn Kixmoeller
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Penn Center for Genome Integrity, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Graduate Program in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Praveen Kumar Allu
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Penn Center for Genome Integrity, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ben E Black
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Penn Center for Genome Integrity, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Graduate Program in Biochemistry and Molecular Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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20
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Conti D, Gul P, Islam A, Martín-Durán JM, Pickersgill RW, Draviam VM. Kinetochores attached to microtubule-ends are stabilised by Astrin bound PP1 to ensure proper chromosome segregation. eLife 2019; 8:49325. [PMID: 31808746 PMCID: PMC6930079 DOI: 10.7554/elife.49325] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 12/01/2019] [Indexed: 12/12/2022] Open
Abstract
Microtubules segregate chromosomes by attaching to macromolecular kinetochores. Only microtubule-end attached kinetochores can be pulled apart; how these end-on attachments are selectively recognised and stabilised is not known. Using the kinetochore and microtubule-associated protein, Astrin, as a molecular probe, we show that end-on attachments are rapidly stabilised by spatially-restricted delivery of PP1 near the C-terminus of Ndc80, a core kinetochore-microtubule linker. PP1 is delivered by the evolutionarily conserved tail of Astrin and this promotes Astrin’s own enrichment creating a highly-responsive positive feedback, independent of biorientation. Abrogating Astrin:PP1-delivery disrupts attachment stability, which is not rescued by inhibiting Aurora-B, an attachment destabiliser, but is reversed by artificially tethering PP1 near the C-terminus of Ndc80. Constitutive Astrin:PP1-delivery disrupts chromosome congression and segregation, revealing a dynamic mechanism for stabilising attachments. Thus, Astrin-PP1 mediates a dynamic ‘lock’ that selectively and rapidly stabilises end-on attachments, independent of biorientation, and ensures proper chromosome segregation.
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Affiliation(s)
- Duccio Conti
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Parveen Gul
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Asifa Islam
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - José M Martín-Durán
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Richard W Pickersgill
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| | - Viji M Draviam
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom.,Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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21
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Amin MA, Agarwal S, Varma D. Mapping the kinetochore MAP functions required for stabilizing microtubule attachments to chromosomes during metaphase. Cytoskeleton (Hoboken) 2019; 76:398-412. [PMID: 31454167 DOI: 10.1002/cm.21559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 08/07/2019] [Accepted: 08/22/2019] [Indexed: 12/24/2022]
Abstract
In mitosis, faithful chromosome segregation is orchestrated by the dynamic interactions between the spindle microtubules (MTs) emanating from the opposite poles and the kinetochores of the chromosomes. However, the precise mechanism that coordinates the coupling of the kinetochore components to dynamic MTs has been a long-standing question. Microtubule-associated proteins (MAPs) regulate MT nucleation and dynamics, MT-mediated transport and MT cross-linking in cells. During mitosis, MAPs play an essential role not only in determining spindle length, position, and orientation but also in facilitating robust kinetochore-microtubule (kMT) attachments by linking the kinetochores to spindle MTs efficiently. The stability of MTs imparted by the MAPs is critical to ensure accurate chromosome segregation. This review primarily focuses on the specific function of nonmotor kinetochore MAPs, their recruitment to kinetochores and their MT-binding properties. We also attempt to synthesize and strengthen our understanding of how these MAPs work in coordination with the kinetochore-bound Ndc80 complex (the key component at the MT-binding interface in metaphase and anaphase) to establish stable kMT attachments and control accurate chromosome segregation during mitosis.
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Affiliation(s)
- Mohammed A Amin
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Shivangi Agarwal
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Dileep Varma
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
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22
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The mammalian kinetochore-microtubule interface: robust mechanics and computation with many microtubules. Curr Opin Cell Biol 2019; 60:60-67. [PMID: 31132675 DOI: 10.1016/j.ceb.2019.04.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/10/2019] [Accepted: 04/15/2019] [Indexed: 12/31/2022]
Abstract
The kinetochore drives chromosome segregation at cell division. It acts as a physical link between chromosomes and dynamic microtubules, and as a signaling hub detecting and processing microtubule attachments to control anaphase onset. The mammalian kinetochore is a large macromolecular machine that forms a dynamic interface with the many microtubules that it binds. While we know most of the kinetochore's component parts, how they work together to give rise to its robust functions remains poorly understood. Here we highlight recent findings that shed light on this question, driven by an expanding physical and molecular toolkit. We present emerging principles that underlie the kinetochore's robust microtubule grip, such as redundancy, specialization, and dynamicity, and present signal processing principles that connect this microtubule grip to robust computation. Throughout, we identify open questions, and define simple engineering concepts that provide insight into kinetochore function.
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23
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Li M, Li A, Zhou S, Lv H, Yang W. SPAG5 upregulation contributes to enhanced c-MYC transcriptional activity via interaction with c-MYC binding protein in triple-negative breast cancer. J Hematol Oncol 2019; 12:14. [PMID: 30736840 PMCID: PMC6367803 DOI: 10.1186/s13045-019-0700-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Accepted: 01/22/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype that lacks effective therapeutic targets. Sperm-associated antigen 5 (SPAG5) is a mitotic spindle-associated protein that is involved in various biological processes in cervical cancer and bladder urothelial carcinoma. However, the role of SPAG5 in TNBC remains undefined. METHODS The expression of SPAG5 was examined in TNBC patients via quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and immunohistochemistry (IHC). The biological functions of SPAG5 in TNBC and the underlying mechanisms were investigated in vitro and in vivo. RESULTS SPAG5 expression was significantly upregulated in TNBC tissues compared with that in paired adjacent noncancerous tissues (ANTs). High SPAG5 expression was associated with increased lymph node metastasis and high risk of local recurrence. SPAG5 protein expression was significantly associated with poor disease-free survival in TNBC. Gene set enrichment analysis of TNBC data from The Cancer Genome Atlas (TCGA) indicated that high SPAG5 expression was significantly associated with cell cycle and the ATR-BRCA pathway. Functional assays demonstrated that SPAG5 expression promoted tumor growth in vitro and in vivo. In addition, SPAG5-silenced cells were more sensitive to the PARP inhibitor (PARPi) olaparib. Mechanistically, SPAG5 interacted with c-MYC binding protein (MYCBP), thereby increasing MYCBP protein levels and leading to increased c-MYC transcriptional activity, which promoted the expression of the c-MYC target genes: CDC20, CDC25C, BRCA1, BRCA2, and RAD51.Knockdown of MYCBP or c-MYC abolished the SPAG5-induced cell-cycle progression and cell proliferation of TNBC. CONCLUSIONS Collectively, our results indict that SPAG5 is an efficient prognostic factor in TNBC, and that SPAG5 knockdown increases the sensitivity of TNBC to the PARPi olaparib. SPAG5 promotes tumor growth and DNA repair by increasing c-MYC transcriptional activity via interaction with MYCBP. The SPAG5/MYCBP/c-MYC axis may represent a potential therapeutic target for TNBC treatment.
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Affiliation(s)
- Ming Li
- Department of Pathology, Fudan University Shanghai Cancer Center, 270 Dongan Road, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.,Institute of Pathology, Fudan University, Shanghai, China
| | - Anqi Li
- Department of Pathology, Fudan University Shanghai Cancer Center, 270 Dongan Road, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.,Institute of Pathology, Fudan University, Shanghai, China
| | - Shuling Zhou
- Department of Pathology, Fudan University Shanghai Cancer Center, 270 Dongan Road, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.,Institute of Pathology, Fudan University, Shanghai, China
| | - Hong Lv
- Department of Pathology, Fudan University Shanghai Cancer Center, 270 Dongan Road, Shanghai, 200032, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.,Institute of Pathology, Fudan University, Shanghai, China
| | - Wentao Yang
- Department of Pathology, Fudan University Shanghai Cancer Center, 270 Dongan Road, Shanghai, 200032, China. .,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China. .,Institute of Pathology, Fudan University, Shanghai, China.
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24
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Edzuka T, Goshima G. Drosophila kinesin-8 stabilizes the kinetochore-microtubule interaction. J Cell Biol 2018; 218:474-488. [PMID: 30538142 PMCID: PMC6363442 DOI: 10.1083/jcb.201807077] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 10/24/2018] [Accepted: 11/28/2018] [Indexed: 02/06/2023] Open
Abstract
Kinesin-8 motor proteins control chromosome alignment in a variety of species, but the specific biochemical activity responsible is unclear. Edzuka and Goshima find that Drosophila kinesin-8 (Klp67A) exhibits both microtubule plus end–stabilizing and –destabilizing activities in vitro. In cells, Klp67A, and likely human kinesin-8 (KIF18A) as well, stabilize the kinetochore–microtubule attachment during mitosis. Kinesin-8 is required for proper chromosome alignment in a variety of animal and yeast cell types. However, it is unclear how this motor protein family controls chromosome alignment, as multiple biochemical activities, including inconsistent ones between studies, have been identified. Here, we find that Drosophila kinesin-8 (Klp67A) possesses both microtubule (MT) plus end–stabilizing and –destabilizing activity, in addition to kinesin-8's commonly observed MT plus end–directed motility and tubulin-binding activity in vitro. We further show that Klp67A is required for stable kinetochore–MT attachment during prometaphase in S2 cells. In the absence of Klp67A, abnormally long MTs interact in an “end-on” fashion with kinetochores at normal frequency. However, the interaction is unstable, and MTs frequently become detached. This phenotype is rescued by ectopic expression of the MT plus end–stabilizing factor CLASP, but not by artificial shortening of MTs. We show that human kinesin-8 (KIF18A) is also important to ensure proper MT attachment. Overall, these results suggest that the MT-stabilizing activity of kinesin-8 is critical for stable kinetochore–MT attachment.
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Affiliation(s)
- Tomoya Edzuka
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan.,Marine Biological Laboratory, Woods Hole, MA
| | - Gohta Goshima
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan .,Marine Biological Laboratory, Woods Hole, MA
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25
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Monda JK, Cheeseman IM. The kinetochore-microtubule interface at a glance. J Cell Sci 2018; 131:131/16/jcs214577. [PMID: 30115751 DOI: 10.1242/jcs.214577] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Accurate chromosome segregation critically depends on the formation of attachments between microtubule polymers and each sister chromatid. The kinetochore is the macromolecular complex that assembles at the centromere of each chromosome during mitosis and serves as the link between the DNA and the microtubules. In this Cell Science at a Glance article and accompanying poster, we discuss the activities and molecular players that are involved in generating kinetochore-microtubule attachments, including the initial stages of lateral kinetochore-microtubule interactions and maturation to stabilized end-on attachments. We additionally explore the features that contribute to the ability of the kinetochore to track with dynamic microtubules. Finally, we examine the contributions of microtubule-associated proteins to the organization and stabilization of the mitotic spindle and the control of microtubule dynamics.
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Affiliation(s)
- Julie K Monda
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA.,Department of Biology, MIT, Cambridge, MA 02142, USA
| | - Iain M Cheeseman
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA .,Department of Biology, MIT, Cambridge, MA 02142, USA
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26
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Petsalaki E, Dandoulaki M, Zachos G. Chmp4c is required for stable kinetochore-microtubule attachments. Chromosoma 2018; 127:461-473. [PMID: 29968190 DOI: 10.1007/s00412-018-0675-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 06/21/2018] [Accepted: 06/26/2018] [Indexed: 01/20/2023]
Abstract
Formation of stable kinetochore-microtubule attachments is essential for accurate chromosome segregation in human cells and depends on the NDC80 complex. We recently showed that Chmp4c, an endosomal sorting complex required for transport protein involved in membrane remodelling, localises to prometaphase kinetochores and promotes cold-stable kinetochore microtubules, faithful chromosome alignment and segregation. In the present study, we show that Chmp4c associates with the NDC80 components Hec1 and Nuf2 and is required for optimal NDC80 stability and Hec1-Nuf2 localisation to kinetochores in prometaphase. However, Chmp4c-depletion does not cause a gross disassembly of outer or inner kinetochore complexes. Conversely, Nuf2 is required for Chmp4c kinetochore targeting. Constitutive Chmp4c kinetochore tethering partially rescues cold-stable microtubule polymers in cells depleted of the endogenous Nuf2, showing that Chmp4c also contributes to kinetochore-microtubule stability independently of regulating Hec1 and Nuf2 localisation. Chmp4c interacts with tubulin in cell extracts, and binds and bundles microtubules in vitro through its highly basic N-terminal region (amino acids 1-77). Furthermore, the N-terminal region of Chmp4c is required for cold-stable kinetochore microtubules and efficient chromosome alignment. We propose that Chmp4c promotes stable kinetochore-microtubule attachments by regulating Hec1-Nuf2 localisation to kinetochores in prometaphase and by binding to spindle microtubules. These results identify Chmp4c as a novel protein that regulates kinetochore-microtubule interactions to promote accurate chromosome segregation in human cells.
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Affiliation(s)
- Eleni Petsalaki
- Department of Biology, University of Crete, Vassilika Vouton, 70013, Heraklion, Greece
| | - Maria Dandoulaki
- Department of Biology, University of Crete, Vassilika Vouton, 70013, Heraklion, Greece
| | - George Zachos
- Department of Biology, University of Crete, Vassilika Vouton, 70013, Heraklion, Greece.
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27
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Platani M, Samejima I, Samejima K, Kanemaki MT, Earnshaw WC. Seh1 targets GATOR2 and Nup153 to mitotic chromosomes. J Cell Sci 2018; 131:jcs.213140. [PMID: 29618633 PMCID: PMC5992584 DOI: 10.1242/jcs.213140] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/23/2018] [Indexed: 12/27/2022] Open
Abstract
In metazoa, the Nup107 complex (also known as the nucleoporin Y-complex) plays a major role in formation of the nuclear pore complex in interphase and is localised to kinetochores in mitosis. The Nup107 complex shares a single highly conserved subunit, Seh1 (also known as SEH1L in mammals) with the GATOR2 complex, an essential activator of mTORC1 kinase. mTORC1/GATOR2 has a central role in the coordination of cell growth and proliferation. Here, we use chemical genetics and quantitative chromosome proteomics to study the role of the Seh1 protein in mitosis. Surprisingly, Seh1 is not required for the association of the Nup107 complex with mitotic chromosomes, but it is essential for the association of both the GATOR2 complex and nucleoporin Nup153 with mitotic chromosomes. Our analysis also reveals a role for Seh1 at human centromeres, where it is required for efficient localisation of the chromosomal passenger complex (CPC). Furthermore, this analysis detects a functional interaction between the Nup107 complex and the small kinetochore protein SKAP (also known as KNSTRN). Highlighted Article: The nucleoporin Seh1 is essential for the association of both the GATOR2 complex and the nucleoporin Nup153, but not the Nup107 complex, with mitotic chromosomes.
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Affiliation(s)
- Melpomeni Platani
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Itaru Samejima
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Kumiko Samejima
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
| | - Masato T Kanemaki
- Division of Molecular Cell Engineering, National Institute of Genetics, ROIS, and Department of Genetics, SOKENDAI, Yata 1111, Mishima, Shizuoka 411-8540, Japan
| | - William C Earnshaw
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh EH9 3BF, UK
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