scholarly journals Centripetal nuclear shape fluctuations associate with chromatin condensation towards mitosis

2021 ◽  
Author(s):  
Viola Introini ◽  
Gururaj Rao Kidiyoor ◽  
Giancarlo Porcella ◽  
Marco Foiani ◽  
Pietro Cicuta ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Cell Cycle Progression ◽  
Chromatin Condensation ◽  
Nuclear Shape ◽  
Cycle Progression ◽  
Cellular Processes ◽  
Nuclear Envelope Breakdown ◽  
Nuclear Mechanics ◽  
Nuclear Processes

The cell nucleus plays a central role in several key cellular processes, including chromosome organisation, replication and transcription. Recent work intriguingly suggests an association between nuclear mechanics and cell-cycle progression, but many aspects of this connection remain unexplored. Here, by monitoring nuclear shape fluctuations at different cell cycle stages, we uncover increasing inward fluctuations in late G2 and early mitosis, which are initially transient, but develop into instabilities that culminate into nuclear-envelope breakdown in mitosis. Perturbation experiments and correlation analysis reveal an association of these processes with chromatin condensation. We propose that the contrasting forces between an extensile stress and centripetal pulling from chromatin condensation could link mechanically chromosome condensation and nuclear-envelope breakdown, the two main nuclear processes during mitosis.

scholarly journals Lamin B1 Polymorphism Influences Morphology of the Nuclear Envelope, Cell Cycle Progression, and Risk of Neural Tube Defects in Mice

PLoS Genetics ◽  
2012 ◽  
Vol 8 (11) ◽  
pp. e1003059 ◽  
Author(s):  
Sandra C. P. De Castro ◽  
Ashraf Malhas ◽  
Kit-Yi Leung ◽  
Peter Gustavsson ◽  
David J. Vaux ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Neural Tube ◽  
Neural Tube Defects ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Lamin B1

scholarly journals Regulation of cell cycle drivers by Cullin-RING ubiquitin ligases

2020 ◽  
Vol 52 (10) ◽  
pp. 1637-1651 ◽  
Author(s):  
Sang-Min Jang ◽  
Christophe E. Redon ◽  
Bhushan L. Thakur ◽  
Meriam K. Bahta ◽  
Mirit I. Aladjem
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Cycle Progression ◽  
Ubiquitin Ligases ◽  
Anaphase Promoting Complex ◽  
Cycle Progression ◽  
Cellular Processes ◽  
Cellular Pathways ◽  
Regulation Of Cell Cycle ◽  
F Box Protein

Abstract The last decade has revealed new roles for Cullin-RING ubiquitin ligases (CRLs) in a myriad of cellular processes, including cell cycle progression. In addition to CRL1, also named SCF (SKP1-Cullin 1-F box protein), which has been known for decades as an important factor in the regulation of the cell cycle, it is now evident that all eight CRL family members are involved in the intricate cellular pathways driving cell cycle progression. In this review, we summarize the structure of CRLs and their functions in driving the cell cycle. We focus on how CRLs target key proteins for degradation or otherwise alter their functions to control the progression over the various cell cycle phases leading to cell division. We also summarize how CRLs and the anaphase-promoting complex/cyclosome (APC/C) ligase complex closely cooperate to govern efficient cell cycle progression.

scholarly journals Tyr198 is the Essential Autophosphorylation Site for STK16 Localization and Kinase Activity

2019 ◽  
Vol 20 (19) ◽  
pp. 4852 ◽  
Author(s):  
Junjun Wang ◽  
Juanjuan Liu ◽  
Xinmiao Ji ◽  
Xin Zhang
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Activity ◽  
Kinase Domain ◽  
Serine Threonine Kinase ◽  
Cycle Progression ◽  
Threonine Kinase ◽  
Cellular Processes ◽  
Activation Segment ◽  
And Function

STK16, reported as a Golgi localized serine/threonine kinase, has been shown to participate in multiple cellular processes, including the TGF-β signaling pathway, TGN protein secretion and sorting, as well as cell cycle and Golgi assembly regulation. However, the mechanisms of the regulation of its kinase activity remain underexplored. It was known that STK16 is autophosphorylated at Thr185, Ser197, and Tyr198 of the activation segment in its kinase domain. We found that STK16 localizes to the cell membrane and the Golgi throughout the cell cycle, but mutations in the auto-phosphorylation sites not only alter its subcellular localization but also affect its kinase activity. In particular, the Tyr198 mutation alone significantly reduced the kinase activity of STK16, abolished its Golgi and membrane localization, and affected the cell cycle progression. This study demonstrates that a single site autophosphorylation of STK16 could affect its localization and function, which provides insights into the molecular regulatory mechanism of STK16’s kinase activity.

Characterization of HDACI OSU42 as a Novel Histone Deacetylase Inhibitor in AML Cell Lines.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1988-1988
Author(s):  
Jin Sun ◽  
Shujun Liu ◽  
Jianhua Yu ◽  
Min Wei ◽  
Charlene Mao ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Gene Silencing ◽  
Cell Cycle Progression ◽  
Chromatin Condensation ◽  
Regulation Of Gene Expression ◽  
Histone H3 ◽  
Malignant Cells ◽  
Cycle Progression ◽  
Nb4 Cells ◽  
Histone Hypoacetylation

Abstract Histone acetylation plays a key role in the regulation of gene expression. Histone hyperacetylation is associated with chromatin opening and gene transcription, while histone hypoacetylation is associated with chromatin condensation and gene silencing. Abnormal histone hypoacetylation mediated by aberrant activity of histone deacetylases (HDACs) has been found to be associated with silencing of tumor suppressor and growth inhibitory genes in malignant cells. HDAC inhibitors (HDACIs) can relieve HDAC-mediated gene silencing and thereby induce normal patterns of cell cycle, differentiation and apoptosis in malignant cells. HDACI OSU 42 is a novel hydroxamate tethered phenylbutyrate derivative that was designed and synthesized at our institution, and exhibited IC50s at submicromolar level, compared with millimolar level for other members of this classes of HDACIs such as valproic acid (VPA). We characterized the activity of this compound in acute myeloid leukemia (AML) cells. It is known that the fusion proteins AML1/ETO and PML / RAR alpha that characterized t(8;21) and t(15;17) AML silence target genes through recruitment of HDACs to their promoter regions. Therefore we utilized AML1/ETO-positive Kasumi-1 and PML/RARA-positive NB4 cells to test the activity of HDACI OSU 42 and used THP-1 cells, characterized by AF9/MLL fusion gene, as a control. We hypothesized that by virtue of the fusion genes, Kasumi-1 and NB4 are more susceptible to HDACI treatment. IC50s for proliferation inhibition in Kasumi-1 cells treated with HDACI OSU42 were 71.8±14.3nM for 24hr and 31.3± 0.4nM for 48hr, significantly lower than VPA (2.0mM for 24hr, 0.9mM for 48hr). The IC50s for NB4 were 237.7±6.5nM for 24hr and 119±6.4nM for 48hr. As a contrast, IC50 for THP-1 was 507.3±68.3nM for 48hr. HDACI OSU42 inhibited 80% of total HDAC activity at 125nM in both Kasumi-1 and NB4; 30nM HDACI OSU42 induced hyperacetylation of histone H3 and H4. Apoptosis analysis showed that nearly 60% more of Kasumi-1 and NB4 underwent apoptosis after treated with 1μM of HDACI OSU42 for 24hr, compared with their untreated control. On the other hand, the same treatment only induced 15% more of THP-1 undergoing apoptosis. Apoptotic effect of HDACI OSU42 was mediated by activation of caspase 9 and caspase 3. Cell cycle analysis demonstrated that treatment of Kasumi-1 and NB4 with 150nM of HDACI OSU 42 inhibited cell cycle progression and arrested 20% to 30% more cells at S phase or G2/M phase, whereas this treatment had not effect on cell cycle progression of THP-1. This was consistent with the up-regulated expression of p21 at both transcription level and protein level. Q-PCR data suggested that Kasumi-1 and NB4 treated with HDACI OSU42 expressed ~10 folds of p21 higher than untreated cells. Chromatin immunoprecipitation assay revealed 10 to 50 folds increase in acetylation level of histone H3 and H4 associated with p21 promoter. Kasumi-1 and NB4 cells also show differentiation ability (increase in CD14 and CD 13 expression by flow cytometry) when treated with 30nM of HDACI OSU42, whereas THP-1 remained undifferentiated. These results support the activity of HDACI OSU42 as a new potent HDACI in AML.

Epigenetic dynamics across the cell cycle

2010 ◽  
Vol 48 ◽  
pp. 107-120 ◽  
Author(s):  
Tony Bou Kheir ◽  
Anders H. Lund
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Cell Cycle Progression ◽  
Current Knowledge ◽  
Chromatin Condensation ◽  
Chromatin Modifications ◽  
Cycle Progression ◽  
Daughter Cells ◽  
Mammalian Cell Cycle ◽  
Regulate Cell Cycle Progression

Progression of the mammalian cell cycle depends on correct timing and co-ordination of a series of events, which are managed by the cellular transcriptional machinery and epigenetic mechanisms governing genome accessibility. Epigenetic chromatin modifications are dynamic across the cell cycle, and are shown to influence and be influenced by cell-cycle progression. Chromatin modifiers regulate cell-cycle progression locally by controlling the expression of individual genes and globally by controlling chromatin condensation and chromosome segregation. The cell cycle, on the other hand, ensures a correct inheritance of epigenetic chromatin modifications to daughter cells. In this chapter, we summarize the current knowledge on the dynamics of epigenetic chromatin modifications during progression of the cell cycle.

scholarly journals KDP-1 is a nuclear envelope KASH protein required for cell-cycle progression

2009 ◽  
Vol 122 (16) ◽  
pp. 2895-2905 ◽  
Author(s):  
M. D. McGee ◽  
I. Stagljar ◽  
D. A. Starr
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Cell Cycle Progression ◽  
Cycle Progression

scholarly journals Mechanosensitive Expression of Lamellipodin Governs Cell Cycle Progression and Intracellular Stiffness

2020 ◽  
Author(s):  
Joseph A. Brazzo ◽  
Kwonmoo Lee ◽  
Yongho Bae
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Migration ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Cycle Progression ◽  
Cellular Processes ◽  
M Phase ◽  
And Migration ◽  
In Cells

SUMMARYCells exhibit pathological behaviors in response to increased extracellular matrix (ECM) stiffness, including accelerated cell proliferation and migration [1–9], which are correlated with increased intracellular stiffness and tension [2, 3, 10–12]. The biomechanical signal transduction of ECM stiffness into relevant molecular signals and resultant cellular processes is mediated through multiple proteins associated with the actin cytoskeleton in lamellipodia [2, 3, 10, 11, 13]. However, the molecular mechanisms by which lamellipodial dynamics regulate cellular responses to ECM stiffening remain unclear. Previous work described that lamellipodin, a phosphoinositide- and actin filament-binding protein that is known mostly for controlling cell migration [14–21], promotes ECM stiffness-mediated early cell cycle progression [2], revealing a potential commonality between the mechanisms controlling stiffness-dependent cell migration and those controlling cell proliferation. However, i) whether and how ECM stiffness affects the levels of lamellipodin expression and ii) whether stiffness-mediated lamellipodin expression is required throughout cell cycle progression and for intracellular stiffness have not been explored. Here, we show that the levels of lamellipodin expression in cells are significantly increased by a stiff ECM and that this stiffness-mediated lamellipodin upregulation persistently stimulates cell cycle progression and intracellular stiffness throughout the cell cycle, from the early G1 phase to M phase. Finally, we show that both Rac activation and intracellular stiffening are required for the mechanosensitive induction of lamellipodin. More specifically, inhibiting Rac1 activation in cells on stiff ECM reduces the levels of lamellipodin expression, and this effect is reversed by the overexpression of activated Rac1 in cells on soft ECM. We thus propose that lamellipodin is a critical molecular lynchpin in the control of mechanosensitive cell cycle progression and intracellular stiffness.

scholarly journals Spatial control of nucleoporin assembly by Fragile X-related proteins

2019 ◽  
Author(s):  
Arantxa Agote-Arán ◽  
Stephane Schmucker ◽  
Katerina Jerabkova ◽  
Inès Jmel Boyer ◽  
Alessandro Berto ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Nuclear Envelope ◽  
Fragile X Syndrome ◽  
Cell Cycle Progression ◽  
Fragile X ◽  
Nuclear Pore ◽  
Nuclear Morphology ◽  
Nuclear Pore Complexes ◽  
Cycle Progression ◽  
Pore Complexes

SummaryNucleoporins (Nups) build highly organized Nuclear Pore Complexes (NPCs) at the nuclear envelope (NE). Several Nups assemble into a sieve-like hydrogel within the central channel of the NPCs to regulate nucleocytoplasmic exchange. In the cytoplasm, a large excess of soluble Nups has been reported, but how their assembly is restricted to the NE is currently unknown. Here we show that Fragile X-related protein 1 (FXR1) can interact with several Nups and facilitate their localization to the NE during interphase through a microtubule and dynein-dependent mechanism. Downregulation of FXR1 or closely related orthologs FXR2 and Fragile X mental retardation protein (FMRP) leads to the accumulation of cytoplasmic Nup protein condensates. Likewise, several models of Fragile X syndrome (FXS), characterized by a loss of FMRP, also accumulate cytoplasmic Nup aggregates. These aggregate-containing cells display aberrant nuclear morphology and a delay in G1 cell cycle progression. Our results reveal an unexpected role for the FXR protein family and dynein in the spatial regulation of nucleoporin assembly.HighlightsCytoplasmic nucleoporins are assembled by Fragile X-related (FXR) proteins and dyneinFXR-Dynein pathway downregulation induces aberrant cytoplasmic aggregation of nucleoporinsCellular models of Fragile X syndrome accumulate aberrant cytoplasmic nucleoporin aggregates.FXR-Dynein pathway regulates nuclear morphology and G1 cell cycle progressioneTOC BlurbNucleoporins (Nups) form Nuclear Pore Complexes (NPCs) at the nuclear envelope. Agote-Arán at al. show how cells inhibit aberrant assembly of Nups in the cytoplasm and identify Fragile X-related (FXR) proteins and dynein that facilitate localization of Nups to the nuclear envelope and control G1 cell cycle progression.Graphical abstract

scholarly journals Src-transformed cells hijack mitosis to extrude from the epithelium

2018 ◽  
Author(s):  
Katarzyna A. Anton ◽  
Mihoko Kajita ◽  
Rika Narumi ◽  
Yasuyuki Fujita ◽  
Masazumi Tada
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Apical Part ◽  
Transformed Cells ◽  
Cycle Progression ◽  
Cellular Processes ◽  
Initial Stage ◽  
Apical Extrusion

AbstractAt the initial stage of carcinogenesis single mutated cells appear within an epithelium. Mammalian in vitro experiments show that potentially cancerous cells undergo live apical extrusion from normal monolayers. However, the mechanism underlying this process in vivo remains poorly understood. Mosaic expression of the oncogene vSrc in a simple epithelium of the early zebrafish embryo results in apical extrusion of transformed cells. Here we find that during extrusion components of the cytokinetic ring are recruited to adherens junctions of transformed cells, stimulating formation of a misoriented pseudo cytokinetic ring. During extrusion, the ring constricts and separates the basal from the apical part of the cell releasing both from the epithelium. This process requires cell cycle progression and occurs immediately after vSrc-transformed cell enters mitosis. To achieve extrusion, vSrc coordinates cell cycle progression, junctional integrity, cell survival and apicobasal polarity. Without vSrc, modulating these cellular processes reconstitutes vSrc-like extrusion, confirming their sufficiency for this process.

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