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The Journal of Pharmacy and Pharmacology Apr 2023Haploid germ cell-specific nuclear protein kinase (Haspin) is a serine/threonine kinase as an atypical kinase, which is structurally distinct from conventional protein... (Review)
Review
OBJECTIVES
Haploid germ cell-specific nuclear protein kinase (Haspin) is a serine/threonine kinase as an atypical kinase, which is structurally distinct from conventional protein kinases.
KEY FINDINGS
Functionally, Haspin is involved in important cell cycle progression, particularly in critical mitosis regulating centromeric sister chromatid cohesion during prophase and prometaphase, and subsequently ensuring proper chromosome alignment during metaphase and the normal chromosome segregation during anaphase. However, increasing evidence has demonstrated that Haspin is significantly upregulated in a variety of cancer cells in addition to normal proliferating somatic cells. Its knockdown or small molecule inhibition could prevent cancer cell growth and induce apoptosis by disrupting the regular mitotic progression. Given the specificity of its expressed tissues or cells and the uniqueness of its current known substrate, Haspin can be a promising target against cancer. Consequently, selective synthetic and natural inhibitors of Haspin have been widely developed to determine their inhibitory power for various cancer cells in vivo and in vitro.
SUMMARY
Here our perspective includes a comprehensive review of the roles and structure of Haspin, its relatively potent and selective inhibitors and Haspin's preliminary studies in a variety of cancers.
Topics: Humans; Antimitotic Agents; Phosphorylation; Intracellular Signaling Peptides and Proteins; Protein Serine-Threonine Kinases; Mitosis; Neoplasms
PubMed: 36334086
DOI: 10.1093/jpp/rgac080 -
Cell Cycle (Georgetown, Tex.) Jul 2020To maintain genome stability, chromosomes must be equally distributed among daughter cells at the end of mitosis. The accuracy of chromosome segregation requires... (Review)
Review
To maintain genome stability, chromosomes must be equally distributed among daughter cells at the end of mitosis. The accuracy of chromosome segregation requires sister-kinetochores to stably attach to microtubules emanating from opposite spindle poles. However, initial kinetochore-microtubule interactions are able to turnover so that defective attachment configurations that typically arise during early mitosis may be corrected. Growing evidence supports a role for the RZZ complex in preventing the stabilization of erroneous kinetochore-microtubule attachments. This inhibitory function of RZZ toward end-on attachments is relieved by DYNEIN-mediated transport of the complex as chromosomes congress and appropriate interactions with microtubules are established. However, it remains unclear how DYNEIN is antagonized to prevent premature RZZ removal. We recently described a new mechanism that sheds new light on this matter. We found that POLO kinase phosphorylates the DYNEIN adaptor SPINDLY to promote the uncoupling between RZZ and DYNEIN. Elevated POLO activity during prometaphase ensures that RZZ is retained at kinetochores to allow the dynamic turnover of kinetochore-microtubule interactions and prevent the stabilization of erroneous attachments. Here, we discuss additional interpretations to explain a model for POLO-dependent regulation of the RZZ-SPINDLY-DYNEIN module during mitosis.
Topics: Animals; Cell Cycle Proteins; Chromosome Segregation; Dyneins; Humans; Kinetochores; Mitosis
PubMed: 32544383
DOI: 10.1080/15384101.2020.1780382 -
Cell Discovery May 2022Noncoding RNAs are known to associate with mitotic chromosomes, but the identities and functions of chromosome-associated RNAs in mitosis remain elusive. Here, we show...
Noncoding RNAs are known to associate with mitotic chromosomes, but the identities and functions of chromosome-associated RNAs in mitosis remain elusive. Here, we show that rRNA species associate with condensed chromosomes during mitosis. In particular, pre-rRNAs such as 45S, 32S, and 30S are highly enriched on mitotic chromosomes. Immediately following nucleolus disassembly in mitotic prophase, rRNAs are released and associate with and coat each condensed chromosome at prometaphase. Using unbiased mass spectrometry analysis, we further demonstrate that chromosome-bound rRNAs are associated with Ki-67. Moreover, the FHA domain and the repeat region of Ki-67 recognize and anchor rRNAs to chromosomes. Finally, suppression of chromosome-bound rRNAs by RNA polymerase I inhibition or by using rRNA-binding-deficient Ki-67 mutants impair mitotic chromosome dispersion during prometaphase. Our study thus reveals an important role of rRNAs in preventing chromosome clustering during mitosis.
PubMed: 35637200
DOI: 10.1038/s41421-022-00400-7 -
Frontiers in Cell and Developmental... 2021The division of one cell into two looks so easy, as if it happens without any control at all. Mitosis, the hallmark of mammalian life is, however, tightly regulated from... (Review)
Review
The division of one cell into two looks so easy, as if it happens without any control at all. Mitosis, the hallmark of mammalian life is, however, tightly regulated from the early onset to the very last phase. Despite the tight control, errors in mitotic division occur frequently and they may result in various chromosomal instabilities and malignancies. The flow of events during mitotic progression where the chromosomes condensate and rearrange with the help of the cytoskeletal network has been described in great detail. Plasma membrane dynamics and endocytic vesicle movement upon deadhesion and reattachment of dividing cells are also demonstrated to be functionally important for the mitotic integrity. Other cytoplasmic organelles, such as autophagosomes and lysosomes, have until recently been considered merely as passive bystanders in this process. Accordingly, at the onset of nuclear envelope breakdown in prometaphase, the number of autophagic structures and lysosomes is reduced and the bulk autophagic machinery is suppressed for the duration of mitosis. This is believed to ensure that the exposed nuclear components are not unintentionally delivered to autophagic degradation. With the evolving technologies that allow the detection of subtle alterations in cytoplasmic organelles, our understanding of the small-scale regulation of intracellular organelles has deepened rapidly and we discuss here recent discoveries revealing unexpected roles for autophagy and lysosomes in the preservation of genomic integrity during mitosis.
PubMed: 34485308
DOI: 10.3389/fcell.2021.727538 -
Developmental Biology Feb 2021The early stages of development involve complex sequences of morphological changes that are both reproducible from embryo to embryo and often robust to environmental...
The early stages of development involve complex sequences of morphological changes that are both reproducible from embryo to embryo and often robust to environmental variability. To investigate the relationship between reproducibility and robustness we examined cell cycle progression in early Drosophila embryos at different temperatures. Our experiments show that while the subdivision of cell cycle steps is conserved across a wide range of temperatures (5-35 °C), the relative duration of individual steps varies with temperature. We find that the transition into prometaphase is delayed at lower temperatures relative to other cell cycle events, arguing that it has a different mechanism of regulation. Using an in vivo biosensor, we quantified the ratio of activities of the major mitotic kinase, Cdk1 and one of the major mitotic phosphatases PP1. Comparing activation profile with cell cycle transition times at different temperatures indicates that in early fly embryos activation of Cdk1 drives entry into prometaphase but is not required for earlier cell cycle events. In fact, chromosome condensation can still occur when Cdk1 activity is inhibited pharmacologically. These results demonstrate that different kinases are rate-limiting for different steps of mitosis, arguing that robust inter-regulation may be needed for rapid and ordered mitosis.
Topics: Animals; CDC2 Protein Kinase; Cell Cycle; Cell Cycle Checkpoints; Cyclin B; Drosophila Proteins; Drosophila melanogaster; Embryo, Nonmammalian; Enzyme Activation; Metaphase; Mitosis; Prometaphase; Prophase; Protein Phosphatase 1; Temperature
PubMed: 33278404
DOI: 10.1016/j.ydbio.2020.11.010 -
Cell Reports Aug 2023Centromere localization of the chromosome passenger complex (CPC) is paramount for achieving accurate sister chromosome segregation in mitosis. Although it has been...
Centromere localization of the chromosome passenger complex (CPC) is paramount for achieving accurate sister chromosome segregation in mitosis. Although it has been widely recognized that the recruitment of CPC is directly regulated by two histone codes, phosphorylation of histone H3 at threonine 3 (H3T3ph) and phosphorylation of histone H2A at threonine 120 (H2AT120ph), the regulation of CPC localization by other histone codes remains elusive. We show that dysfunction of disruptor of telomeric silencing 1 like (DOT1L) leads to mislocation of the CPC in prometaphase, caused by disturbing the level of H3T3ph and its reader Survivin. This cascade is initiated by over-dephosphorylation of H3T3ph mediated by the phosphatase RepoMan-PP1, whose scaffold RepoMan translocalizes to chromosomes, while the level of H3K79me2/3 is diminished. Together, our findings uncover a biological function of DOT1L and H3K79 methylation in mitosis and give insight into how genomic stability is coordinated by different histone codes.
Topics: Histones; Protein Serine-Threonine Kinases; Methylation; Centromere; Mitosis; Aurora Kinase B; Phosphorylation; Threonine
PubMed: 37494186
DOI: 10.1016/j.celrep.2023.112885 -
European Journal of Medical Research Dec 2023Hepatocellular carcinoma (HCC) is one of the most prevalent forms of cancer and poses a threat to the health and survival of humans. Mitochondrial ribosomal protein L48...
BACKGROUND
Hepatocellular carcinoma (HCC) is one of the most prevalent forms of cancer and poses a threat to the health and survival of humans. Mitochondrial ribosomal protein L48 (MRPL48) belongs to the mitochondrial ribosomal protein family, which participates in energy production. Studies have shown that MRPL48 can predict osteosarcoma incidence and prognosis, as well as promotes colorectal cancer progression. However, the role of MRPL48 in HCC remains unknown.
METHODS
TCGA, GEO, HCCDB, CPTAC, SMART, UALCAN, Kaplan-Meier plotter, cBioPortal, and MethSurv were performed for bioinformatics purposes. Quantitative RT-PCR, immunoblotting, and functional studies were conducted to validate the methodology in vitro.
RESULTS
MRPL48 was greatly overexpressed in HCC tissues, compared with healthy tissue, which was subsequently demonstrated in vitro as well. The survival and regression analyses showed that MRPL48 expression is of significant clinical prognostic value in HCC. The ROC curve and nomogram analysis indicated that MRPL48 is a powerful predictor of HCC. MRPL48 methylation was adversely associated with the expression of MRPL48, and patients with a low level of methylation had poorer overall survival than those with a high level of methylation. GSEA showed that the expression of the MRPL48 was correlated with Resolution of Sister Chromatid Cohesion, Mitotic Prometaphase, Retinoblastoma Gene in Cancer, RHO Gtpases Activate Formins, Mitotic Metaphase and Anaphase, and Cell Cycle Checkpoints. An analysis of immune cell infiltration showed a significant association between MRPL48 and immune cell infiltration subsets, which impacted the survival of HCC patients. Additionally, MRPL48 knockdown reduced HCC cell proliferation, migration, and invasion in vitro.
CONCLUSIONS
We demonstrated that MRPL48 expression may be associated with HCC development and prognosis. These findings may open up new research directions and opportunities for the development of HCC treatments.
Topics: Humans; Prognosis; Carcinoma, Hepatocellular; Liver Neoplasms; Biomarkers; Ribosomal Proteins
PubMed: 38093387
DOI: 10.1186/s40001-023-01571-z -
The EMBO Journal May 2023Various cancer types exhibit characteristic and recurrent aneuploidy patterns. The origins of these cancer type-specific karyotypes are still unknown, partly because...
Various cancer types exhibit characteristic and recurrent aneuploidy patterns. The origins of these cancer type-specific karyotypes are still unknown, partly because introducing or eliminating specific chromosomes in human cells still poses a challenge. Here, we describe a novel strategy to induce mis-segregation of specific chromosomes in different human cell types. We employed Tet repressor or nuclease-dead Cas9 to link a microtubule minus-end-directed kinesin (Kinesin14VIb) from Physcomitrella patens to integrated Tet operon repeats and chromosome-specific endogenous repeats, respectively. By live- and fixed-cell imaging, we observed poleward movement of the targeted loci during (pro)metaphase. Kinesin14VIb-mediated pulling forces on the targeted chromosome were counteracted by forces from kinetochore-attached microtubules. This tug-of-war resulted in chromosome-specific segregation errors during anaphase and revealed that spindle forces can heavily stretch chromosomal arms. By single-cell whole-genome sequencing, we established that kinesin-induced targeted mis-segregations predominantly result in chromosomal arm aneuploidies after a single cell division. Our kinesin-based strategy opens the possibility to investigate the immediate cellular responses to specific aneuploidies in different cell types; an important step toward understanding how tissue-specific aneuploidy patterns evolve.
Topics: Humans; Kinesins; Spindle Apparatus; Kinetochores; Microtubules; Chromosome Segregation; Anaphase; Aneuploidy
PubMed: 37038978
DOI: 10.15252/embj.2022111559 -
Molecular Biology of the Cell May 2021In prophase of meiosis I, homologous chromosomes pair and become connected by cross-overs. Chiasmata, the connections formed by cross-overs, enable the chromosome pair,...
In prophase of meiosis I, homologous chromosomes pair and become connected by cross-overs. Chiasmata, the connections formed by cross-overs, enable the chromosome pair, called a bivalent, to attach as a single unit to the spindle. When the meiotic spindle forms in prometaphase, most bivalents are associated with one spindle pole and then go through a series of oscillations on the spindle, attaching to and detaching from microtubules until the partners of the bivalent become bioriented-attached to microtubules from opposite sides of the spindle. The conserved kinase, Mps1, is essential for the bivalents to be pulled by microtubules across the spindle in prometaphase. Here we show that is needed for efficient triggering of the migration of microtubule-attached kinetochores toward the poles and promotes microtubule depolymerization. Our data support the model Mps1 acts at the kinetochore to coordinate the successful attachment of a microtubule and the triggering of microtubule depolymerization to then move the chromosome.
Topics: Cell Polarity; Chromosome Pairing; Chromosomes; Kinetochores; Microtubules; Mutation; Prometaphase; Protein Serine-Threonine Kinases; Saccharomyces cerevisiae Proteins; Saccharomycetales
PubMed: 33788584
DOI: 10.1091/mbc.E20-08-0525-T -
Life (Basel, Switzerland) May 2022Variants of linker histone H1 are tissue-specific and are responsible for chromatin compaction accompanying cell differentiation, mitotic chromosome condensation, and...
The Highest Density of Phosphorylated Histone H1 Appeared in Prophase and Prometaphase in Parallel with Reduced H3K9me3, and HDAC1 Depletion Increased H1.2/H1.3 and H1.4 Serine 38 Phosphorylation.
BACKGROUND
Variants of linker histone H1 are tissue-specific and are responsible for chromatin compaction accompanying cell differentiation, mitotic chromosome condensation, and apoptosis. Heterochromatinization, as the main feature of these processes, is also associated with pronounced trimethylation of histones H3 at the lysine 9 position (H3K9me3).
METHODS
By confocal microscopy, we analyzed cell cycle-dependent levels and distribution of phosphorylated histone H1 (H1ph) and H3K9me3. By mass spectrometry, we studied post-translational modifications of linker histones.
RESULTS
Phosphorylated histone H1, similarly to H3K9me3, has a comparable level in the G1, S, and G2 phases of the cell cycle. A high density of phosphorylated H1 was inside nucleoli of mouse embryonic stem cells (ESCs). H1ph was also abundant in prophase and prometaphase, while H1ph was absent in anaphase and telophase. H3K9me3 surrounded chromosomal DNA in telophase. This histone modification was barely detectable in the early phases of mitosis. Mass spectrometry revealed several ESC-specific phosphorylation sites of H1. HDAC1 depletion did not change H1 acetylation but potentiated phosphorylation of H1.2/H1.3 and H1.4 at serine 38 positions.
CONCLUSIONS
Differences in the level and distribution of H1ph and H3K9me3 were revealed during mitotic phases. ESC-specific phosphorylation sites were identified in a linker histone.
PubMed: 35743829
DOI: 10.3390/life12060798