bims-micesi 2022-06-19 papers

bims-micesi

Biomed News

on Mitotic cell signalling

Issue of 2022–06–19
seven papers selected by
Valentina Piano, Max Planck Institute of Molecular Physiology

Haspin participates in AURKB recruitment to centromeres and contributes to chromosome congression in male mouse meiosis.
Aurora B activity is promoted by cooperation between discrete localization sites in budding yeast.
Factor quinolinone inhibitors disrupt spindles and multiple LSF (TFCP2)-protein interactions in mitosis, including with microtubule-associated proteins.
Anillin governs mitotic rounding during early epidermal development.
Polymer models reveal how chromatin modification can modulate force at the kinetochore.
The cell cycle gene centromere protein K (CENPK) contributes to the malignant progression and prognosis of prostate cancer.
Anti-tumor pharmacology of natural products targeting mitosis.

J Cell Sci. 2022 Jun 13. pii: jcs.259546. [Epub ahead of print]

Haspin participates in AURKB recruitment to centromeres and contributes to chromosome congression in male mouse meiosis.

Berenguer I, P López-Jiménez, I Mena, A Viera, J Page, J González-Martínez, C Maestre, M Malumbres, J A Suja, R Gómez.

  Chromosome segregation requires that centromeres properly attach to spindle microtubules. This essential step regulates the accuracy of cell division and therefore must be precisely regulated. One of the main centromeric regulatory signaling pathways is the Haspin-H3T3ph-chromosomal passenger complex (CPC) cascade, which is responsible for the recruitment of the CPC to the centromeres. In mitosis, Haspin kinase phosphorylates histone H3 at threonine 3 (H3T3ph), an essential epigenetic mark that recruits the CPC, whose catalytic component is Aurora B kinase. However, the centromeric Haspin-H3T3ph-CPC pathway remains largely uncharacterized in mammalian male meiosis. We have analyzed Haspin functions by either its chemical inhibition in cultured spermatocytes using LDN-192960, or the ablation of Haspin gene in Haspin-/-. Our studies suggest that Haspin kinase activity is required for proper chromosome congression during both meiotic divisions and for the recruitment of Aurora B and kinesin MCAK to meiotic centromeres. However, the absence of H3T3ph histone mark does not alter Borealin and SGO2 centromeric localization. These results add new and relevant information regarding the regulation of the Haspin-H3T3ph-CPC pathway and centromere function during meiosis.

Keywords:  AURKB; Centromere; H3T3ph; Haspin; Meiosis

DOI:  https://doi.org/10.1242/jcs.259546
Mol Biol Cell. 2022 Jun 15. mbcE21110590

Aurora B activity is promoted by cooperation between discrete localization sites in budding yeast.

Theodor Marsoner, Poornima Yedavalli, Chiara Masnovo, Sarah Fink, Katrin Schmitzer, Christopher S Campbell.

Chromosome biorientation is promoted by the four-member chromosomal passenger complex (CPC) through phosphorylation of incorrect kinetochore-microtubule attachments. During chromosome alignment, the CPC localizes to the inner centromere, the inner kinetochore and spindle microtubules. Here we show that a small domain of the CPC subunit INCENP/Sli15 is required to target the complex to all three of these locations in budding yeast. This domain, the SAH, is essential for phosphorylation of outer kinetochore substrates, chromosome segregation, and viability. By restoring the CPC to each of these three locations through targeted mutations and fusion constructs, we determined their individual contributions to chromosome biorientation. We find that only the inner centromere localization is sufficient for cell viability on its own. However, when combined, the inner kinetochore and microtubule binding activities are also sufficient to promote accurate chromosome segregation. Furthermore, we find that the two pathways target the CPC to different kinetochore attachment states, as the inner centromere-targeting pathway is primarily responsible for bringing the complex to unattached kinetochores. We have therefore discovered that two parallel localization pathways are each sufficient to promote CPC activity in chromosome biorientation, both depending on the SAH domain of INCENP/Sli15.

DOI: https://doi.org/10.1091/mbc.E21-11-0590
PLoS One. 2022 ;17(6): e0268857

Factor quinolinone inhibitors disrupt spindles and multiple LSF (TFCP2)-protein interactions in mitosis, including with microtubule-associated proteins.

Sarah A Yunes, Jennifer L S Willoughby, Julian H Kwan, Jessica M Biagi, Niranjana Pokharel, Hang Gyeong Chin, Emily A York, Kuan-Chung Su, Kelly George, Jagesh V Shah, Andrew Emili, Scott E Schaus, Ulla Hansen.

Factor quinolinone inhibitors (FQIs), a first-in-class set of small molecule inhibitors targeted to the transcription factor LSF (TFCP2), exhibit promising cancer chemotherapeutic properties. FQI1, the initial lead compound identified, unexpectedly induced a concentration-dependent delay in mitotic progression. Here, we show that FQI1 can rapidly and reversibly lead to mitotic arrest, even when added directly to mitotic cells, implying that FQI1-mediated mitotic defects are not transcriptionally based. Furthermore, treatment with FQIs resulted in a striking, concentration-dependent diminishment of spindle microtubules, accompanied by a concentration-dependent increase in multi-aster formation. Aberrant γ-tubulin localization was also observed. These phenotypes suggest that perturbation of spindle microtubules is the primary event leading to the mitotic delays upon FQI1 treatment. Previously, FQIs were shown to specifically inhibit not only LSF DNA-binding activity, which requires LSF oligomerization to tetramers, but also other specific LSF-protein interactions. Other transcription factors participate in mitosis through non-transcriptional means, and we recently reported that LSF directly binds α-tubulin and is present in purified cellular tubulin preparations. Consistent with a microtubule role for LSF, here we show that LSF enhanced the rate of tubulin polymerization in vitro, and FQI1 inhibited such polymerization. To probe whether the FQI1-mediated spindle abnormalities could result from inhibition of mitotic LSF-protein interactions, mass spectrometry was performed using as bait an inducible, tagged form of LSF that is biotinylated by endogenous enzymes. The global proteomics analysis yielded expected associations for a transcription factor, notably with RNA processing machinery, but also to nontranscriptional components. In particular, and consistent with spindle disruption due to FQI treatment, mitotic, FQI1-sensitive interactions were identified between the biotinylated LSF and microtubule-associated proteins that regulate spindle assembly, positioning, and dynamics, as well as centrosome-associated proteins. Probing the mitotic LSF interactome using small molecule inhibitors therefore supported a non-transcriptional role for LSF in mediating progression through mitosis.

DOI: https://doi.org/10.1371/journal.pone.0268857
BMC Biol. 2022 Jun 16. 20(1): 145

Anillin governs mitotic rounding during early epidermal development.

Adnan Mahly, Krishnanand Padmanabhan, Arad Soffer, Jonathan Cohen, Jana Omar, Ronit Sagi-Eisenberg, Chen Luxenburg.

   BACKGROUND: The establishment of tissue architecture requires coordination between distinct processes including basement membrane assembly, cell adhesion, and polarity; however, the underlying mechanisms remain poorly understood. The actin cytoskeleton is ideally situated to orchestrate tissue morphogenesis due to its roles in mechanical, structural, and regulatory processes. However, the function of many pivotal actin-binding proteins in mammalian development is poorly understood.
RESULTS: Here, we identify a crucial role for anillin (ANLN), an actin-binding protein, in orchestrating epidermal morphogenesis. In utero RNAi-mediated silencing of Anln in mouse embryos disrupted epidermal architecture marked by adhesion, polarity, and basement membrane defects. Unexpectedly, these defects cannot explain the profoundly perturbed epidermis of Anln-depleted embryos. Indeed, even before these defects emerge, Anln-depleted epidermis exhibits abnormalities in mitotic rounding and its associated processes: chromosome segregation, spindle orientation, and mitotic progression, though not in cytokinesis that was disrupted only in Anln-depleted cultured keratinocytes. We further show that ANLN localizes to the cell cortex during mitotic rounding, where it regulates the distribution of active RhoA and the levels, activity, and structural organization of the cortical actomyosin proteins.
CONCLUSIONS: Our results demonstrate that ANLN is a major regulator of epidermal morphogenesis and identify a novel role for ANLN in mitotic rounding, a near-universal process that governs cell shape, fate, and tissue morphogenesis.

Keywords:  Actin; Adhesion; Anillin; Cytokinesis; Development; Epidermis; Mitotic rounding; Morphogenesis; Skin

DOI:  https://doi.org/10.1186/s12915-022-01345-9
Mol Biol Cell. 2022 Jun 15. mbcE22020041

Polymer models reveal how chromatin modification can modulate force at the kinetochore.

Josh Lawrimore, Solenn C de Larminat, Diana Cook, Brandon Friedman, Ayush Doshi, Elaine Yeh, Kerry Bloom.

A key feature of chromosome segregation is the ability to sense tension between sister kinetochores. DNA between sister kinetochores must be packaged in a way that sustains tension propagation from one kinetochore to its sister, approximately 1 micron away. A molecular bottlebrush consisting of a primary axis populated with a crowded array of side chains provides a means to build tension over length scales considerably larger than the stiffness of the individual elements, i.e., DNA polymer. Evidence for the bottlebrush organization of chromatin between sister kinetochores comes from genetic, cell biological, and polymer modeling of the budding yeast centromere. In this study, we have used polymer dynamic simulations of the bottlebrush to recapitulate experimental observations of kinetochore structure. Several aspects of the spatial distribution of kinetochore proteins and their response to perturbation lack a mechanistic understanding. Changes in physical parameters of bottlebrush, DNA stiffness, and DNA loops directly impact the architecture of the inner kinetochore. This study reveals that the bottlebrush is an active participant in building tension between sister kinetochores and proposes a mechanism for chromatin feedback to the kinetochore.

DOI: https://doi.org/10.1091/mbc.E22-02-0041
Transl Cancer Res. 2022 May;11(5): 1099-1111

The cell cycle gene centromere protein K (CENPK) contributes to the malignant progression and prognosis of prostate cancer.

Xuanrong Chen, Yi Shao, Yang Li, Zhao Yang, Yutong Chen, Wenyue Yu, Zhiqun Shang, Wanqing Wei.

   Background: The cell cycle gene centromere protein K (CENPK) is upregulated in various cancers; however, the clinical value and mechanism of CENPK in prostate cancer (PCa) and castration-resistant prostate cancer (CRPC) remain unclear.
Methods: The expression of CENPK in PCa was analyzed in both patients with PCa and cell lines using immunohistochemistry (IHC), real-time quantitative reverse transcription PCR (qRT-PCR), Western blot and bioinformatics analyses. Knockdown of CENPK in PCa cells was achieved by transfecting siRNAs and assessed using qRT-PCR and Western blotting. MTT and colony formation assays were used to assess the growth of PCa cells. The cell cycle was analyzed using propidium iodide (PI) staining and flow cytometry. To study the possible biological function of CENPK, pathway enrichment analysis was performed by dividing these groups into a high CENPK expression group and a low CENPK expression group based on the median CENPK expression level. Finally, the correlation between CENPK expression in PCa and clinical parameters was evaluated.
Results: Our study revealed that CENPK was expressed at high levels in CRPC tissues and cell lines compared to primary PCa. The downregulation of CENPK significantly inhibited cell viability and reduced the number of colonies formed by LNCaP-AI and DU145 cells (two CRPC cell lines). Gene enrichment and flow cytometry analyses showed that high CENPK expression was linked to mitotic spindles and the cell cycle and may be involved in mitosis in the cell cycle of cancer cells to modulate cell proliferation and promote the development of CRPC. Moreover, patients exhibiting higher expression of the CENPK mRNA experienced shorter disease-free survival (DFS) and overall survival (OS) than the lower expression group.
Conclusions: This study provides novel molecular insights into the role of CENPK in castration-resistant PCa cells and reveals that an increase in CENPK expression may indicate shorter DFS and a poor prognosis for patients with PCa. Targeting CENPK may be a novel strategy for the treatment of PCa.

Keywords:  Centromere protein K (CENPK); cell cycle; prognosis; progression; prostate cancer (PCa)

DOI:  https://doi.org/10.21037/tcr-21-2164
Cancer Biol Med. 2022 Jun 15. pii: j.issn.2095-3941.2022.0006. [Epub ahead of print]

Anti-tumor pharmacology of natural products targeting mitosis.

Manru Huang, Caiyan Liu, Yingying Shao, Shiyue Zhou, Gaoyong Hu, Shuangshuang Yin, Weiling Pu, Haiyang Yu.

  Cancer has been an insurmountable problem in the history of medical science. The uncontrollable proliferation of cancer cells is one of cancer's main characteristics, which is closely associated with abnormal mitosis. Targeting mitosis is an effective method for cancer treatment. This review summarizes several natural products with anti-tumor effects related to mitosis, focusing on targeting microtubulin, inducing DNA damage, and modulating mitosis-associated kinases. Furthermore, the main disadvantages of several typical compounds, including drug resistance, toxicity to non-tumor tissues, and poor aqueous solubility and pharmacokinetic properties, are also discussed, together with strategies to address them. Improved understanding of cancer cell mitosis and natural products may pave the way to drug development for the treatment of cancer.

Keywords:  Tumor; mechanism; mitosis; natural products; pharmacology

DOI:  https://doi.org/10.20892/j.issn.2095-3941.2022.0006