bims-micesi 2022-04-10 papers

bims-micesi

Biomed News

on Mitotic cell signalling

Issue of 2022–04–10
ten papers selected by
Valentina Piano, Max Planck Institute of Molecular Physiology

Mad2 promotes Cyclin B2 recruitment to the kinetochore for guiding accurate mitotic checkpoint.
Structure of the RZZ complex and molecular basis of Spindly-driven corona assembly at human kinetochores.
The spindle assembly checkpoint and the spatial activation of Polo kinase determine the duration of cell division and prevent tumor formation.
Augmin-dependent microtubule self-organization drives kinetochore fiber maturation in mammals.
Aurora kinase A inhibition induces synthetic lethality in SMAD4-deficient colorectal cancer cells via spindle assembly checkpoint activation.
Ser68 phosphoregulation is essential for CENP-A deposition, centromere function and viability in mice.
Mitotic protein kinase-driven crosstalk of machineries for mitosis and metastasis.
PKM2 Interacts With the Cdk1-CyclinB Complex to Facilitate Cell Cycle Progression in Gliomas.
Quantifying chromosomal instability from intratumoral karyotype diversity using agent-based modeling and Bayesian inference.
Domain Adaptive Box-supervised Instance Segmentation Network for Mitosis Detection.

EMBO Rep. 2022 Apr 05. e54171

Mad2 promotes Cyclin B2 recruitment to the kinetochore for guiding accurate mitotic checkpoint.

Sikai Liu, Xiao Yuan, Ping Gui, Ran Liu, Olanrewaju Durojaye, Donald L Hill, Chuanhai Fu, Xuebiao Yao, Zhen Dou, Xing Liu.

  Accurate mitotic progression relies on the dynamic phosphorylation of multiple substrates by key mitotic kinases. Cyclin-dependent kinase 1 is a master kinase that coordinates mitotic progression and requires its regulatory subunit Cyclin B to ensure full kinase activity and substrate specificity. The function of Cyclin B2, which is a closely related family member of Cyclin B1, remains largely elusive. Here, we show that Mad2 promotes the kinetochore localization of Cyclin B2 and that their interaction at the kinetochores guides accurate chromosome segregation. Our biochemical analyses have characterized the Mad2-Cyclin B2 interaction and delineated a novel Mad2-interacting motif (MIM) on Cyclin B2. The functional importance of the Cyclin B2-Mad2 interaction was demonstrated by real-time imaging in which MIM-deficient mutant Cyclin B2 failed to rescue the chromosomal segregation defects. Taken together, we have delineated a previously undefined function of Cyclin B2 at the kinetochore and have established, in human cells, a mechanism of action by which Mad2 contributes to the spindle checkpoint.

Keywords:  Mad2; cyclin B2; kinetochore; mitosis; spindle assembly checkpoint

DOI:  https://doi.org/10.15252/embr.202154171
EMBO J. 2022 Apr 04. e110411

Structure of the RZZ complex and molecular basis of Spindly-driven corona assembly at human kinetochores.

Tobias Raisch, Giuseppe Ciossani, Ennio d'Amico, Verena Cmentowski, Sara Carmignani, Stefano Maffini, Felipe Merino, Sabine Wohlgemuth, Ingrid R Vetter, Stefan Raunser, Andrea Musacchio.

  In metazoans, a ≈1 megadalton (MDa) multiprotein complex comprising the dynein-dynactin adaptor Spindly and the ROD-Zwilch-ZW10 (RZZ) complex is the building block of a fibrous biopolymer, the kinetochore fibrous corona. The corona assembles on mitotic kinetochores to promote microtubule capture and spindle assembly checkpoint (SAC) signaling. We report here a high-resolution cryo-EM structure that captures the essential features of the RZZ complex, including a farnesyl-binding site required for Spindly binding. Using a highly predictive in vitro assay, we demonstrate that the SAC kinase MPS1 is necessary and sufficient for corona assembly at supercritical concentrations of the RZZ-Spindly (RZZS) complex, and describe the molecular mechanism of phosphorylation-dependent filament nucleation. We identify several structural requirements for RZZS polymerization in rings and sheets. Finally, we identify determinants of kinetochore localization and corona assembly of Spindly. Our results describe a framework for the long-sought-for molecular basis of corona assembly on metazoan kinetochores.

Keywords:  RZZ; centromere; fibrous corona; kinetochore; spindle assembly checkpoint

DOI:  https://doi.org/10.15252/embj.2021110411
PLoS Genet. 2022 Apr 04. 18(4): e1010145

The spindle assembly checkpoint and the spatial activation of Polo kinase determine the duration of cell division and prevent tumor formation.

Emmanuel Gallaud, Laurent Richard-Parpaillon, Laetitia Bataillé, Aude Pascal, Mathieu Métivier, Vincent Archambault, Régis Giet.

The maintenance of a restricted pool of asymmetrically dividing stem cells is essential for tissue homeostasis. This process requires the control of mitotic progression that ensures the accurate chromosome segregation. In addition, this event is coupled to the asymmetric distribution of cell fate determinants in order to prevent stem cell amplification. How this coupling is regulated remains poorly described. Here, using asymmetrically dividing Drosophila neural stem cells (NSCs), we show that Polo kinase activity levels determine timely Cyclin B degradation and mitotic progression independent of the spindle assembly checkpoint (SAC). This event is mediated by the direct phosphorylation of Polo kinase by Aurora A at spindle poles and Aurora B kinases at centromeres. Furthermore, we show that Aurora A-dependent activation of Polo is the major event that promotes NSC polarization and together with the SAC prevents brain tumor growth. Altogether, our results show that an Aurora/Polo kinase module couples NSC mitotic progression and polarization for tissue homeostasis.

DOI: https://doi.org/10.1371/journal.pgen.1010145
Cell Rep. 2022 Apr 05. pii: S2211-1247(22)00358-8. [Epub ahead of print]39(1): 110610

Augmin-dependent microtubule self-organization drives kinetochore fiber maturation in mammals.

Ana C Almeida, Joana Soares-de-Oliveira, Danica Drpic, Liam P Cheeseman, Joana Damas, Harris A Lewin, Denis M Larkin, Paulo Aguiar, António J Pereira, Helder Maiato.

  Chromosome segregation in mammals relies on the maturation of a thick bundle of kinetochore-attached microtubules known as k-fiber. How k-fibers mature from initial kinetochore microtubule attachments remains a fundamental question. By combining molecular perturbations and phenotypic analyses in Indian muntjac fibroblasts containing the lowest known diploid chromosome number in mammals (2N = 6) and distinctively large kinetochores, with fixed/live-cell super-resolution coherent-hybrid stimulated emission depletion (CH-STED) nanoscopy and laser microsurgery, we demonstrate a key role for augmin in kinetochore microtubule self-organization and maturation, regardless of pioneer centrosomal microtubules. In doing so, augmin promotes kinetochore and interpolar microtubule turnover and poleward flux. Tracking of microtubule growth events within individual k-fibers reveals a wide angular dispersion, consistent with augmin-mediated branched microtubule nucleation. Augmin depletion reduces the frequency of kinetochore microtubule growth events and hampers efficient repair after acute k-fiber injury by laser microsurgery. Together, these findings underscore the contribution of augmin-mediated microtubule amplification for k-fiber self-organization and maturation in mammals.

Keywords:  CP: Cell biology; Indian muntjac; augmin; coherent-hybrid STED; k-fiber; kinetochore; laser microsurgery; microtubules; mitosis; mitotic spindle; super-resolution

DOI:  https://doi.org/10.1016/j.celrep.2022.110610
Oncogene. 2022 Apr 07.

Aurora kinase A inhibition induces synthetic lethality in SMAD4-deficient colorectal cancer cells via spindle assembly checkpoint activation.

Changxiang Shi, Shishi Tao, Guowen Ren, Eun Ju Yang, Xiaodong Shu, Pui Kei Mou, Yifan Liu, Yongjun Dang, Xiaoling Xu, Joong Sup Shim.

SMAD4 loss-of-function mutations have been frequently observed in colorectal cancer (CRC) and are recognized as a drug target for therapeutic exploitation. In this study, we performed a synthetic lethal drug screening with SMAD4-isogenic CRC cells and found that aurora kinase A (AURKA) inhibition is synthetic lethal with SMAD4 loss. Inhibition of AURKA selectively inhibited the growth of SMAD4-/- CRC in vitro and in vivo. Mechanistically, SMAD4 negatively regulated AURKA level, resulting in the significant elevation of AURKA in SMAD4-/- CRC cells. Inhibition of AURKA induced G2/M cell cycle delay in SMAD4+/+ CRC cells, but induced apoptosis in SMAD4-/- CRC cells. We further observed that a high level of AURKA in SMAD4-/- CRC cells led to abnormal mitotic spindles, leading to cellular aneuploidy. Moreover, SMAD4-/- CRC cells expressed high levels of spindle assembly checkpoint (SAC) proteins, suggesting the hyperactivation of SAC. The silencing of key SAC proteins significantly rescued the AURKA inhibition-induced cell death in SMAD4-/- cells, suggesting that SMAD4-/- CRC cells are hyper-dependent on AURKA activity for mitotic exit and survival during SAC hyperactivation. This study presents a unique synthetic lethal interaction between SMAD4 and AURKA and suggests that AURKA could be a potential drug target in SMAD4-deficient CRC.

DOI: https://doi.org/10.1038/s41388-022-02293-y
Sci China Life Sci. 2022 Apr 01.

Ser68 phosphoregulation is essential for CENP-A deposition, centromere function and viability in mice.

Yuting Liu, Kehui Wang, Li Huang, Jicheng Zhao, Xinpeng Chen, Qiang Wu, Zhouliang Yu, Guohong Li.

  Centromere identity is defined by nucleosomes containing CENP-A, a histone H3 variant. The deposition of CENP-A at centromeres is tightly regulated in a cell-cycle-dependent manner. We previously reported that the spatiotemporal control of centromeric CENP-A incorporation is mediated by the phosphorylation of CENP-A Ser68. However, a recent report argued that Ser68 phosphoregulation is dispensable for accurate CENP-A loading. Here, we report that the substitution of Ser68 of endogenous CENP-A with either Gln68 or Glu68 severely impairs CENP-A deposition and cell viability. We also find that mice harboring the corresponding mutations are lethal. Together, these results indicate that the dynamic phosphorylation of Ser68 ensures cell-cycle-dependent CENP-A deposition and cell viability.

Keywords:  CENP-A; cell cycle; centromere; chromosome segregation; mitosis; phosphorylation

DOI:  https://doi.org/10.1007/s11427-021-2077-1
Exp Mol Med. 2022 Apr 04.

Mitotic protein kinase-driven crosstalk of machineries for mitosis and metastasis.

Chang-Hyeon Kim, Da-Eun Kim, Dae-Hoon Kim, Ga-Hong Min, Jung-Won Park, Yeo-Bin Kim, Chang K Sung, Hyungshin Yim.

Accumulating evidence indicates that mitotic protein kinases are involved in metastatic migration as well as tumorigenesis. Protein kinases and cytoskeletal proteins play a role in the efficient release of metastatic cells from a tumor mass in the tumor microenvironment, in addition to playing roles in mitosis. Mitotic protein kinases, including Polo-like kinase 1 (PLK1) and Aurora kinases, have been shown to be involved in metastasis in addition to cell proliferation and tumorigenesis, depending on the phosphorylation status and cellular context. Although the genetic programs underlying mitosis and metastasis are different, the same protein kinases and cytoskeletal proteins can participate in both mitosis and cell migration/invasion, resulting in migratory tumors. Cytoskeletal remodeling supports several cellular events, including cell division, movement, and migration. Thus, understanding the contributions of cytoskeletal proteins to the processes of cell division and metastatic motility is crucial for developing efficient therapeutic tools to treat cancer metastases. Here, we identify mitotic kinases that function in cancer metastasis as well as tumorigenesis. Several mitotic kinases, namely, PLK1, Aurora kinases, Rho-associated protein kinase 1, and integrin-linked kinase, are considered in this review, as an understanding of the shared machineries between mitosis and metastasis could be helpful for developing new strategies to treat cancer.

DOI: https://doi.org/10.1038/s12276-022-00750-y
Front Oncol. 2022 ;12 844861

PKM2 Interacts With the Cdk1-CyclinB Complex to Facilitate Cell Cycle Progression in Gliomas.

Shigeo Ohba, Yongjian Tang, Tor-Christian Aase Johannessen, Joydeep Mukherjee.

  PKM2 is a phosphotyrosine-binding glycolytic enzyme upregulated in many cancers, including glioma, and contributes to tumor growth by regulating cell cycle progression. We noted, however, that in multiple glioma cell lines, PKM2 knock-down resulted in an accumulation of cells in G2-M phase. Moreover, PKM2 knock-down decreased Cdk1 activity while introducing a constitutively active Cdk1 reversed the effects of PKM2 knock-down on cell cycle progression. The means by which PKM2 increases Cdk1 activity have not been described. Transient interaction of T14/Y15-phosphorylated Cdk1 with cyclin B allows Cdk7-mediated pT161 Cdk1 phosphorylation followed by cdc25C-mediated removal of pT14/Y15 and activation of Cdk1 in cycling cells. In the present course of investigation, PKM2 modulation did not influence Cdk7 activity, but phosphotyrosine binding forms of PKM2 co-immunoprecipitated with pY15-containing Cdk1-cyclinB and enhanced formation of active pT161 Cdk1-cyclin B complexes. Moreover, exogenous expression of phosphotyrosine binding forms of PKM2 reversed the effects of PKM2 knock-down on G2-M arrest. We here show that PKM2 binds and stabilize otherwise transient pY15-containing Cdk1-cyclinB complexes that in turn facilitate Cdk1-cyclin B activation and entry of cells into mitosis. These results, therefore, establish metabolic enzyme PKM2 as a direct interactor and activator of Cdk1-cyclin B complex and thereby directly controls mitotic progression and the growth of brain tumor cells.

Keywords:  Cdk1; G2-M arrest; PKM2; cyclin B; glioma

DOI:  https://doi.org/10.3389/fonc.2022.844861
Elife. 2022 Apr 05. pii: e69799. [Epub ahead of print]11

Quantifying chromosomal instability from intratumoral karyotype diversity using agent-based modeling and Bayesian inference.

Andrew R Lynch, Nicholas L Arp, Amber S Zhou, Beth A Weaver, Mark E Burkard.

  Chromosomal instability (CIN)-persistent chromosome gain or loss through abnormal mitotic segregation-is a hallmark of cancer that drives aneuploidy. Intrinsic chromosome mis-segregation rate, a measure of CIN, can inform prognosis and is a promising biomarker for response to anti-microtubule agents. However, existing methodologies to measure this rate are labor intensive, indirect, and confounded by selection against aneuploid cells, which reduces observable diversity. We developed a framework to measure CIN, accounting for karyotype selection, using simulations with various levels of CIN and models of selection. To identify the model parameters that best fit karyotype data from single-cell sequencing, we used approximate Bayesian computation to infer mis-segregation rates and karyotype selection. Experimental validation confirmed the extensive chromosome mis-segregation rates caused by the chemotherapy paclitaxel (18.5±0.5/division). Extending this approach to clinical samples revealed that inferred rates fell within direct observations of cancer cell lines. This work provides the necessary framework to quantify CIN in human tumors and develop it as a predictive biomarker.

Keywords:  cancer biology; computational biology; human; systems biology

DOI:  https://doi.org/10.7554/eLife.69799
IEEE Trans Med Imaging. 2022 Apr 07. PP

Domain Adaptive Box-supervised Instance Segmentation Network for Mitosis Detection.

Yonghui Li, Yao Xue, Liangfu Li, Xingjun Zhang, Xueming Qian.

The number of mitotic cells present in histopathological slides is an important predictor of tumor proliferation in the diagnosis of breast cancer. However, the current approaches can hardly perform precise pixel-level prediction for mitosis datasets with only weak labels (i.e., only provide the centroid location of mitotic cells), and take no account of the large domain gap across histopathological slides from different pathology laboratories. In this work, we propose a Domain adaptive Box-supervised Instance segmentation Network (DBIN) to address the above issues. In DBIN, we propose a high-performance Box-supervised Instance-Aware (BIA) head with the core idea of redesigning three box-supervised mask loss terms. Furthermore, we add a Pseudo-Mask-supervised Semantic (PMS) head for enriching characteristics extracted from underlying feature maps. Besides, we align the pixel-level feature distributions between source and target domains by a Cross-Domain Adaptive Module (CDAM), so as to adapt the detector learned from one lab can work well on unlabeled data from another lab. The proposed method achieves state-of-the-art performance across four mainstream datasets. A series of analysis and experiments show that our proposed BIA and PMS head can accomplish mitosis pixel-wise localization under weak supervision, and we can boost the generalization ability of our model by CDAM.

DOI: https://doi.org/10.1109/TMI.2022.3165518