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1.
Theranostics ; 14(10): 3927-3944, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38994017

RESUMO

Rationale: Myocardial infarction (MI) is a severe global clinical condition with widespread prevalence. The adult mammalian heart's limited capacity to generate new cardiomyocytes (CMs) in response to injury remains a primary obstacle in developing effective therapies. Current approaches focus on inducing the proliferation of existing CMs through cell-cycle reentry. However, this method primarily elevates cyclin dependent kinase 6 (CDK6) and DNA content, lacking proper cytokinesis and resulting in the formation of dysfunctional binucleated CMs. Cytokinesis is dependent on ribosome biogenesis (Ribo-bio), a crucial process modulated by nucleolin (Ncl). Our objective was to identify a novel approach that promotes both DNA synthesis and cytokinesis. Methods: Various techniques, including RNA/protein-sequencing analysis, Ribo-Halo, Ribo-disome, flow cytometry, and cardiac-specific tumor-suppressor retinoblastoma-1 (Rb1) knockout mice, were employed to assess the series signaling of proliferation/cell-cycle reentry and Ribo-bio/cytokinesis. Echocardiography, confocal imaging, and histology were utilized to evaluate cardiac function. Results: Analysis revealed significantly elevated levels of Rb1, bur decreased levels of circASXL1 in the hearts of MI mice compared to control mice. Deletion of Rb1 induces solely cell-cycle reentry, while augmenting the Ribo-bio modulator Ncl leads to cytokinesis. Mechanically, bioinformatics and the loss/gain studies uncovered that circASXL1/CDK6/Rb1 regulates cell-cycle reentry. Moreover, Ribo-Halo, Ribo-disome and circRNA pull-down assays demonstrated that circASXL1 promotes cytokinesis through Ncl/Ribo-bio. Importantly, exosomes derived from umbilical cord mesenchymal stem cells (UMSC-Exo) had the ability to enhance cardiac function by facilitating the coordinated signaling of cell-cycle reentry and Ribo-bio/cytokinesis. These effects were attenuated by silencing circASXL1 in UMSC-Exo. Conclusion: The series signaling of circASXL1/CDK6/Rb1/cell-cycle reentry and circASXL1/Ncl/Ribo-bio/cytokinesis plays a crucial role in cardiac repair. UMSC-Exo effectively repairs infarcted myocardium by stimulating CM cell-cycle reentry and cytokinesis in a circASXL1-dependent manner. This study provides innovative therapeutic strategies targeting the circASXL1 signaling network for MI and offering potential avenues for enhanced cardiac repair.


Assuntos
Ciclo Celular , Citocinese , Camundongos Knockout , Infarto do Miocárdio , Miócitos Cardíacos , Ribossomos , Animais , Camundongos , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Miócitos Cardíacos/metabolismo , Ribossomos/metabolismo , Fosfoproteínas/metabolismo , Fosfoproteínas/genética , Nucleolina , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Proteína do Retinoblastoma/metabolismo , Proteína do Retinoblastoma/genética , Proliferação de Células , Masculino , Humanos
2.
Methods Mol Biol ; 2814: 1-27, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38954194

RESUMO

The social amoeba Dictyostelium discoideum is a versatile model for understanding many different cellular processes involving cell motility including chemotaxis, phagocytosis, and cytokinesis. Cytokinesis, in particular, is a model cell-shaped change process in which a cell separates into two daughter cells. D. discoideum has been used extensively to identify players in cytokinesis and understand how they comprise the mechanosensory and biochemical pathways of cytokinesis. In this chapter, we describe how we use cDNA library complementation with D. discoideum to discover potential regulators of cytokinesis. Once identified, these regulators are further analyzed through live cell imaging, immunofluorescence imaging, fluorescence correlation and cross-correlation spectroscopy, micropipette aspiration, and fluorescence recovery after photobleaching. Collectively, these methods aid in detailing the mechanisms and signaling pathways that comprise cell division.


Assuntos
Citocinese , Dictyostelium , Dictyostelium/metabolismo , Dictyostelium/genética , Dictyostelium/citologia , Biblioteca Gênica , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Transdução de Sinais , Recuperação de Fluorescência Após Fotodegradação/métodos
3.
Proc Natl Acad Sci U S A ; 121(29): e2320769121, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-38990949

RESUMO

Cytokinesis is the process where the mother cell's cytoplasm separates into daughter cells. This is driven by an actomyosin contractile ring that produces cortical contractility and drives cleavage furrow ingression, resulting in the formation of a thin intercellular bridge. While cytoskeletal reorganization during cytokinesis has been extensively studied, less is known about the spatiotemporal dynamics of the plasma membrane. Here, we image and model plasma membrane lipid and protein dynamics on the cell surface during leukemia cell cytokinesis. We reveal an extensive accumulation and folding of the plasma membrane at the cleavage furrow and the intercellular bridge, accompanied by a depletion and unfolding of the plasma membrane at the cell poles. These membrane dynamics are caused by two actomyosin-driven biophysical mechanisms: the radial constriction of the cleavage furrow causes local compression of the apparent cell surface area and accumulation of the plasma membrane at the furrow, while actomyosin cortical flows drag the plasma membrane toward the cell division plane as the furrow ingresses. The magnitude of these effects depends on the plasma membrane fluidity, cortex adhesion, and cortical contractility. Overall, our work reveals cell-intrinsic mechanical regulation of plasma membrane accumulation at the cleavage furrow that is likely to generate localized differences in membrane tension across the cytokinetic cell. This may locally alter endocytosis, exocytosis, and mechanotransduction, while also serving as a self-protecting mechanism against cytokinesis failures that arise from high membrane tension at the intercellular bridge.


Assuntos
Actomiosina , Membrana Celular , Citocinese , Citocinese/fisiologia , Membrana Celular/metabolismo , Humanos , Actomiosina/metabolismo
4.
Int J Dev Biol ; 68(2): 47-53, 2024 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-39016373

RESUMO

Invertebrate and vertebrate species have many unusual cellular structures, such as long- or short-lived cell-in-cell structures and coenocytes. Coenocytes (often incorrectly described as syncytia) are multinuclear cells derived, unlike syncytia, not from the fusion of multiple cells but from multiple nuclear divisions without cytokinesis. An example of a somatic coenocyte is the coenocytic blastoderm in Drosophila. An astonishing property of coenocytes is the ability to differentiate the nuclei sharing a common cytoplasm into different subpopulations with different fate trajectories. An example of a germline coenocyte is the oogenic precursor of appendicularian tunicates, which shares many features with the somatic coenocyte of Drosophila. The germline coenocyte (coenocyst) is quite an unexpected structure because in most animals, including Drosophila, Xenopus, and mice, oogenesis proceeds within a group (cyst, nest) of sibling cells (cystocytes) connected by the intercellular bridges (ring canals, RCs) derived from multiple divisions with incomplete cytokinesis of a progenitor cell called the cystoblast. Here, I discuss the differences and similarities between cystocyte-based and coenocyst-based oogenesis, and the resemblance of coenocystic oogenesis to coenocytic somatic blastoderm in Drosophila. I also describe cell-in-cell structures that although not mechanistically, cytologically, or molecularly connected to somatic or germline coenocytes, are both unorthodox and intriguing cytological phenomena rarely covered by scientific literature.


Assuntos
Células Germinativas , Oogênese , Animais , Oogênese/fisiologia , Células Germinativas/citologia , Células Germinativas/fisiologia , Drosophila , Células Gigantes/citologia , Células Gigantes/metabolismo , Células Gigantes/fisiologia , Feminino , Camundongos , Citocinese/fisiologia
5.
Nat Commun ; 15(1): 6014, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39019889

RESUMO

Phenotypic heterogeneity in bacteria can result from stochastic processes or deterministic programs. The deterministic programs often involve the versatile second messenger c-di-GMP, and give rise to daughter cells with different c-di-GMP levels by deploying c-di-GMP metabolizing enzymes asymmetrically during cell division. By contrast, less is known about how phenotypic heterogeneity is kept to a minimum. Here, we identify a deterministic c-di-GMP-dependent program that is hardwired into the cell cycle of Myxococcus xanthus to minimize phenotypic heterogeneity and guarantee the formation of phenotypically similar daughter cells during division. Cells lacking the diguanylate cyclase DmxA have an aberrant motility behaviour. DmxA is recruited to the cell division site and its activity is switched on during cytokinesis, resulting in a transient increase in the c-di-GMP concentration. During cytokinesis, this c-di-GMP burst ensures the symmetric incorporation and allocation of structural motility proteins and motility regulators at the new cell poles of the two daughters, thereby generating phenotypically similar daughters with correct motility behaviours. Thus, our findings suggest a general c-di-GMP-dependent mechanism for minimizing phenotypic heterogeneity, and demonstrate that bacteria can ensure the formation of dissimilar or similar daughter cells by deploying c-di-GMP metabolizing enzymes to distinct subcellular locations.


Assuntos
Proteínas de Bactérias , GMP Cíclico , Citocinese , Myxococcus xanthus , Fenótipo , Fósforo-Oxigênio Liases , Citocinese/fisiologia , GMP Cíclico/metabolismo , GMP Cíclico/análogos & derivados , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Fósforo-Oxigênio Liases/metabolismo , Fósforo-Oxigênio Liases/genética , Myxococcus xanthus/metabolismo , Myxococcus xanthus/citologia , Myxococcus xanthus/fisiologia , Myxococcus xanthus/genética , Divisão Celular , Regulação Bacteriana da Expressão Gênica , Proteínas de Escherichia coli
6.
Pak J Biol Sci ; 27(5): 276-282, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38840468

RESUMO

<b>Background and Objective:</b> Gamma irradiation induces genotoxicity, characterized by the formation of extra-nuclear bodies and left behind during the anaphase stage of cell division, often referred to as a micronucleus (MN). The present work aims to monitor exposure to ionizing radiation as a genotoxic agent in the lymphocytes of workers at radiation energy centers. <b>Materials and Methods:</b> The lymphocyte cytokinesis block micronucleus assay used and analyzed the correlation between the Nuclear Division Index (NDI), age, blood type and the number of micronuclei (MN). Blood samples were collected from 20 volunteers in heparin tubes, exposed to 2 Gy gamma rays and cultured <i>in vitro</i>. <b>Results:</b> A significant difference in the number of micronuclei between blood group A and blood groups A, B and AB. The Nuclear Division Index (NDI) value for lymphocytes of radiation energy center workers after gamma radiation was significant (1.74±0.1) but still within the normal range. Neither MN frequency nor NDI values correlated with age, but MN frequency showed a correlation with blood type. <b>Conclusion:</b> The gamma irradiation did not induce a cytostatic effect but proved genotoxic to the lymphocytes of radiation energy center workers. Notably, blood type A demonstrated higher sensitivity to gamma radiation.


Assuntos
Citocinese , Raios gama , Linfócitos , Testes para Micronúcleos , Exposição Ocupacional , Humanos , Raios gama/efeitos adversos , Linfócitos/efeitos da radiação , Linfócitos/metabolismo , Testes para Micronúcleos/métodos , Citocinese/efeitos da radiação , Exposição Ocupacional/efeitos adversos , Adulto , Masculino , Pessoa de Meia-Idade , Micronúcleos com Defeito Cromossômico/efeitos da radiação , Feminino
7.
Microb Cell Fact ; 23(1): 179, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38890717

RESUMO

BACKGROUND: Human lysozyme (hLYZ) is a natural antibacterial protein with broad applications in food and pharmaceutical industries. Recombinant production of hLYZ in Komagataella phaffii (K. phaffii) has attracted considerable attention, but there are very limited strategies for its hyper-production in yeast. RESULTS: Here through Atmospheric and Room Temperature Plasma (ARTP)-based mutagenesis and transcriptomic analysis, the expression of two genes MYO1 and IQG1 encoding the cytokinesis core proteins was identified downregulated along with higher hLYZ production. Deletion of either gene caused severe cytokinesis defects, but significantly enhanced hLYZ production. The highest hLYZ yield of 1,052,444 ± 23,667 U/mL bioactivity and 4.12 ± 0.11 g/L total protein concentration were obtained after high-density fed-batch fermentation in the Δmyo1 mutant, representing the best production of hLYZ in yeast. Furthermore, O-linked mannose glycans were characterized on this recombinant hLYZ. CONCLUSIONS: Our work suggests that cytokinesis-based morphology engineering is an effective way to enhance the production of hLYZ in K. phaffii.


Assuntos
Muramidase , Proteínas Recombinantes , Saccharomycetales , Muramidase/metabolismo , Muramidase/genética , Muramidase/biossíntese , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Saccharomycetales/metabolismo , Saccharomycetales/genética , Humanos , Fermentação , Citocinese , Engenharia Metabólica/métodos , Técnicas de Cultura Celular por Lotes
8.
Proc Natl Acad Sci U S A ; 121(25): e2318838121, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38870057

RESUMO

Hertwig's rule states that cells divide along their longest axis, usually driven by forces acting on the mitotic spindle. Here, we show that in contrast to this rule, microtubule-based pulling forces in early Caenorhabditis elegans embryos align the spindle with the short axis of the cell. We combine theory with experiments to reveal that in order to correct this misalignment, inward forces generated by the constricting cytokinetic ring rotate the entire cell until the spindle is aligned with the cell's long axis. Experiments with slightly compressed mouse zygotes indicate that this cytokinetic ring-driven mechanism of ensuring Hertwig's rule is general for cells capable of rotating inside a confining shell, a scenario that applies to early cell divisions of many systems.


Assuntos
Caenorhabditis elegans , Fuso Acromático , Animais , Caenorhabditis elegans/embriologia , Camundongos , Fuso Acromático/metabolismo , Microtúbulos/metabolismo , Citocinese/fisiologia , Rotação , Zigoto/metabolismo , Zigoto/citologia , Zigoto/crescimento & desenvolvimento , Embrião não Mamífero/citologia , Desenvolvimento Embrionário/fisiologia , Modelos Biológicos
9.
Cell Rep ; 43(6): 114273, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38843397

RESUMO

Phosphoinositides (PtdIns) are a family of differentially phosphorylated lipid second messengers localized to the cytoplasmic leaflet of both plasma and intracellular membranes. Kinases and phosphatases can selectively modify the PtdIns composition of different cellular compartments, leading to the recruitment of specific binding proteins, which control cellular homeostasis and proliferation. Thus, while PtdIns affect cell growth and survival during interphase, they are also emerging as key drivers in multiple temporally defined membrane remodeling events of mitosis, like cell rounding, spindle orientation, cytokinesis, and abscission. In this review, we summarize and discuss what is known about PtdIns function during mitosis and how alterations in the production and removal of PtdIns can interfere with proper cell division.


Assuntos
Mitose , Fosfatidilinositóis , Humanos , Fosfatidilinositóis/metabolismo , Animais , Citocinese/fisiologia
10.
Development ; 151(11)2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38832826

RESUMO

Germline maintenance relies on adult stem cells to continually replenish lost gametes over a lifetime and respond to external cues altering the demands on the tissue. Mating worsens germline homeostasis over time, yet a negative impact on stem cell behavior has not been explored. Using extended live imaging of the Drosophila testis stem cell niche, we find that short periods of mating in young males disrupts cytokinesis in germline stem cells (GSCs). This defect leads to failure of abscission, preventing release of differentiating cells from the niche. We find that GSC abscission failure is caused by increased Ecdysone hormone signaling induced upon mating, which leads to disrupted somatic encystment of the germline. Abscission failure is rescued by isolating males from females, but recurs with resumption of mating. Importantly, reiterative mating also leads to increased GSC loss, requiring increased restoration of stem cells via symmetric renewal and de-differentiation. Together, these results suggest a model whereby acute mating results in hormonal changes that negatively impact GSC cytokinesis but preserves the stem cell population.


Assuntos
Citocinese , Drosophila melanogaster , Ecdisona , Células Germinativas , Testículo , Animais , Masculino , Ecdisona/metabolismo , Testículo/metabolismo , Feminino , Drosophila melanogaster/metabolismo , Células Germinativas/metabolismo , Células Germinativas/citologia , Nicho de Células-Tronco , Células-Tronco/metabolismo , Células-Tronco/citologia , Diferenciação Celular , Transdução de Sinais , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética
11.
Nat Commun ; 15(1): 5250, 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38897998

RESUMO

Cytokinesis is the final step of the cell division cycle that leads to the formation of two new cells. Successful cytokinesis requires significant remodelling of the plasma membrane by spatially distinct ß- and γ-actin networks. These networks are generated by the formin family of actin nucleators, DIAPH3 and DIAPH1 respectively. Here we show that ß- and γ-actin perform specialized and non-redundant roles in cytokinesis and cannot substitute for one another. Expression of hybrid DIAPH1 and DIAPH3 proteins with altered actin isoform specificity relocalized cytokinetic actin isoform networks within the cell, causing cytokinetic failure. Consistent with this we show that ß-actin networks, but not γ-actin networks, are required for the maintenance of non-muscle myosin II and RhoA at the cytokinetic furrow. These data suggest that independent and spatially distinct actin isoform networks form scaffolds of unique interactors that facilitate localized biochemical activities to ensure successful cell division.


Assuntos
Actinas , Proteínas Adaptadoras de Transdução de Sinal , Citocinese , Forminas , Miosina Tipo II , Proteína rhoA de Ligação ao GTP , Proteína rhoA de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/genética , Forminas/metabolismo , Forminas/genética , Actinas/metabolismo , Humanos , Miosina Tipo II/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Células HeLa , Animais , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/genética
12.
J Cell Sci ; 137(12)2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38832513

RESUMO

Division plane positioning is crucial for proper growth and development in many organisms. In plants, the division plane is established before mitosis, by accumulation of a cytoskeletal structure called the preprophase band (PPB). The PPB is thought to be essential for recruitment of division site-localized proteins, which remain at the division site after the PPB disassembles. Here, we show that the division site-localized protein TANGLED1 (TAN1) is recruited independently of the PPB to the cell cortex by the plant cytokinetic machinery, the phragmoplast, from experiments using both the PPB-defective mutant discordia1 (dcd1) and chemical treatments that disrupt the phragmoplast in maize. TAN1 recruitment to de novo sites on the cortex is partially dependent on intact actin filaments and the myosin XI motor protein OPAQUE1 (O1). These data imply a yet unknown role for TAN1 and possibly other division site-localized proteins during the last stages of cell division when the phragmoplast touches the cell cortex to complete cytokinesis.


Assuntos
Citocinese , Proteínas de Plantas , Zea mays , Zea mays/metabolismo , Zea mays/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Citoesqueleto de Actina/metabolismo
13.
Mol Biol Cell ; 35(8): br14, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38865179

RESUMO

Many organisms utilize an actin- and myosin-based cytokinetic ring (CR) to help complete cytokinesis. In Schizosaccharomyces pombe, the Septation Initiation Network (SIN) promotes proper CR function and stability. The SIN is a conserved and essential signaling network consisting of a GTPase and a cascade of kinases assembled at the spindle pole body (SPB). The PP2A SIN inhibitory phosphatase (SIP) complex related to the STRIPAK phosphatase complex is one inhibitor of SIN signaling. The SIP consists of Csc1, Csc2, Csc3, Csc4, Paa1, and the phosphatase subunit Ppa3. Here, we determine that the SIP is anchored at the SPB via the Csc1 FHA domain and that constitutive SPB localization of the SIP is lethal due to persistent SIN inhibition. Disrupting SIP docking at the SPB with a point mutation within the FHA domain or eliminating phosphatase activity by introducing a point mutation within Ppa3 resulted in intact SIP complexes without SIN inhibitory function. Lastly, we defined the unique features of Ppa3 that allow it, but not two other PP2A catalytic subunits, to incorporate into the SIP. Overall, we provide insight into how the SIP complex assembles, localizes, and functions to counteract the SIN with spatiotemporal precision during cytokinesis.


Assuntos
Citocinese , Mitose , Proteína Fosfatase 2 , Proteínas de Schizosaccharomyces pombe , Schizosaccharomyces , Corpos Polares do Fuso , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/metabolismo , Proteína Fosfatase 2/metabolismo , Citocinese/fisiologia , Corpos Polares do Fuso/metabolismo , Domínios Proteicos , Transdução de Sinais , Fuso Acromático/metabolismo
14.
J Cell Sci ; 137(11)2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38770570

RESUMO

Dinoflagellates are marine organisms that undergo seasonal proliferation events known as algal blooms. Vegetative cell proliferation is a main contributing factor in these events. However, mechanistical understanding of mitosis and cytokinesis in dinoflagellates remains rudimentary. Using an optimized immunofluorescence protocol, we analysed changes in microtubule organization occurring during the mitotic cycle of the toxic dinoflagellate Ostreopsis cf. ovata. We find that the flagella and the cortical microtubule array persist throughout the mitotic cycle. Two cytoplasmic microtubule bundles originate from the ventral area, where the basal bodies are located - a cortical bundle and a cytoplasmic bundle. The latter associates with the nucleus in the cell centre before mitosis and with the acentrosomal extranuclear spindle during mitosis. Analysis of tubulin post-translational modifications identifies two populations of spindle microtubules - polar acetylated microtubules, whose length is constant, and central tyrosinated microtubules, which elongate during chromosome segregation. During cell division a microtubule-rich structure forms along the dorsal-ventral axis, associated with the site of cytokinesis, consistent with a cytokinetic mechanism that is independent of the actomyosin ring typical of animal and yeast cells.


Assuntos
Dinoflagellida , Microtúbulos , Mitose , Microtúbulos/metabolismo , Dinoflagellida/metabolismo , Dinoflagellida/citologia , Citocinese , Fuso Acromático/metabolismo , Divisão Celular , Tubulina (Proteína)/metabolismo
15.
Nat Commun ; 15(1): 4023, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38740816

RESUMO

Abscission is the final stage of cytokinesis, which cleaves the intercellular bridge (ICB) connecting two daughter cells. Abscission requires tight control of the recruitment and polymerization of the Endosomal Protein Complex Required for Transport-III (ESCRT-III) components. We explore the role of post-translational modifications in regulating ESCRT dynamics. We discover that SMYD2 methylates the lysine 6 residue of human CHMP2B, a key ESCRT-III component, at the ICB, impacting the dynamic relocation of CHMP2B to sites of abscission. SMYD2 loss-of-function (genetically or pharmacologically) causes CHMP2B hypomethylation, delayed CHMP2B polymerization and delayed abscission. This is phenocopied by CHMP2B lysine 6 mutants that cannot be methylated. Conversely, SMYD2 gain-of-function causes CHMP2B hypermethylation and accelerated abscission, specifically in cells undergoing cytokinetic challenges, thereby bypassing the abscission checkpoint. Additional experiments highlight the importance of CHMP2B methylation beyond cytokinesis, namely during ESCRT-III-mediated HIV-1 budding. We propose that lysine methylation signaling fine-tunes the ESCRT-III machinery to regulate the timing of cytokinetic abscission and other ESCRT-III dependent functions.


Assuntos
Citocinese , Complexos Endossomais de Distribuição Requeridos para Transporte , Histona-Lisina N-Metiltransferase , Humanos , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/genética , Células HeLa , Histona-Lisina N-Metiltransferase/metabolismo , Histona-Lisina N-Metiltransferase/genética , HIV-1/metabolismo , HIV-1/genética , HIV-1/fisiologia , Lisina/metabolismo , Metilação , Processamento de Proteína Pós-Traducional
16.
Mol Biol Cell ; 35(7): ar94, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38696255

RESUMO

Animal cell cytokinesis, or the physical division of one cell into two, is thought to be driven by constriction of an actomyosin contractile ring at the division plane. The mechanisms underlying cell type-specific differences in cytokinesis remain unknown. Germ cells are totipotent cells that pass genetic information to the next generation. Previously, using formincyk-1(ts) mutant Caenorhabditis elegans 4-cell embryos, we found that the P2 germ precursor cell is protected from cytokinesis failure and can divide with greatly reduced F-actin levels at the cell division plane. Here, we identified two canonical germ fate determinants required for P2-specific cytokinetic protection: PIE-1 and POS-1. Neither has been implicated previously in cytokinesis. These germ fate determinants protect P2 cytokinesis by reducing the accumulation of septinUNC-59 and anillinANI-1 at the division plane, which here act as negative regulators of cytokinesis. These findings may provide insight into the regulation of cytokinesis in other cell types, especially in stem cells with high potency.


Assuntos
Actinas , Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Divisão Celular , Citocinese , Células Germinativas , Septinas , Animais , Citocinese/fisiologia , Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/embriologia , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Septinas/metabolismo , Septinas/genética , Células Germinativas/metabolismo , Células Germinativas/citologia , Actinas/metabolismo , Proteínas Contráteis/metabolismo , Actomiosina/metabolismo
17.
J Cell Biol ; 223(8)2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-38727809

RESUMO

Binucleated polyploid cells are common in many animal tissues, where they arise by endomitosis, a non-canonical cell cycle in which cells enter M phase but do not undergo cytokinesis. Different steps of cytokinesis have been shown to be inhibited during endomitosis M phase in rodents, but it is currently unknown how human cells undergo endomitosis. In this study, we use fetal-derived human hepatocyte organoids (Hep-Orgs) to investigate how human hepatocytes initiate and execute endomitosis. We find that cells in endomitosis M phase have normal mitotic timings, but lose membrane anchorage to the midbody during cytokinesis, which is associated with the loss of four cortical anchoring proteins, RacGAP1, Anillin, SEPT9, and citron kinase (CIT-K). Moreover, reduction of WNT activity increases the percentage of binucleated cells in Hep-Orgs, an effect that is dependent on the atypical E2F proteins, E2F7 and E2F8. Together, we have elucidated how hepatocytes undergo endomitosis in human Hep-Orgs, providing new insights into the mechanisms of endomitosis in mammals.


Assuntos
Citocinese , Hepatócitos , Mitose , Organoides , Humanos , Hepatócitos/metabolismo , Organoides/citologia , Organoides/metabolismo , Poliploidia
18.
Sci Rep ; 14(1): 11250, 2024 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755233

RESUMO

The patterns of Formin B and of the Arp2/3 complex formed during mitosis were studied in a mutant of Dictyostelium discoideum that produces multinucleate cells, which divide by the ingression of unilateral cleavage furrows. During cytokinesis the cells of this mutant remain spread on a glass surface where they generate a planar pattern based on the sorting-out of actin-binding proteins. During anaphase, Formin B and Arp2/3 became localized to the regions of microtubule asters around the centrosomes; Formin B in particular in the form of round, quite uniformly covered areas. These areas have been shown to be depleted of myosin II and the actin-filament crosslinker cortexillin, and to be avoided by cleavage furrows on their path into the cell.


Assuntos
Dictyostelium , Proteínas dos Microfilamentos , Microtúbulos , Mitose , Microtúbulos/metabolismo , Dictyostelium/metabolismo , Proteínas dos Microfilamentos/metabolismo , Proteínas dos Microfilamentos/genética , Complexo 2-3 de Proteínas Relacionadas à Actina/metabolismo , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Transporte Proteico , Citocinese , Actinas/metabolismo
19.
Nat Commun ; 15(1): 3779, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38710684

RESUMO

The α-Aurora kinase is a crucial regulator of spindle microtubule organization during mitosis in plants. Here, we report a post-mitotic role for α-Aurora in reorganizing the phragmoplast microtubule array. In Arabidopsis thaliana, α-Aurora relocated from spindle poles to the phragmoplast midzone, where it interacted with the microtubule cross-linker MAP65-3. In a hypomorphic α-Aurora mutant, MAP65-3 was detected on spindle microtubules, followed by a diffuse association pattern across the phragmoplast midzone. Simultaneously, phragmoplast microtubules remained belatedly in a solid disk array before transitioning to a ring shape. Microtubules at the leading edge of the matured phragmoplast were often disengaged, accompanied by conspicuous retentions of MAP65-3 at the phragmoplast interior edge. Specifically, α-Aurora phosphorylated two residues towards the C-terminus of MAP65-3. Mutation of these residues to alanines resulted in an increased association of MAP65-3 with microtubules within the phragmoplast. Consequently, the expansion of the phragmoplast was notably slower compared to wild-type cells or cells expressing a phospho-mimetic variant of MAP65-3. Moreover, mimicking phosphorylation reinstated disrupted MAP65-3 behaviors in plants with compromised α-Aurora function. Overall, our findings reveal a mechanism in which α-Aurora facilitates cytokinesis progression through phosphorylation-dependent restriction of MAP65-3 associating with microtubules at the phragmoplast midzone.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Citocinese , Proteínas Associadas aos Microtúbulos , Microtúbulos , Arabidopsis/metabolismo , Arabidopsis/genética , Microtúbulos/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Fosforilação , Mutação , Fuso Acromático/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Plantas Geneticamente Modificadas , Mitose
20.
Int J Mol Sci ; 25(8)2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38674111

RESUMO

Coatomer Protein Complex-II (COPII) mediates anterograde vesicle transport from the endoplasmic reticulum (ER) to the Golgi apparatus. Here, we report that the COPII coatomer complex is constructed dependent on a small GTPase, Sar1, in spermatocytes before and during Drosophila male meiosis. COPII-containing foci co-localized with transitional endoplasmic reticulum (tER)-Golgi units. They showed dynamic distribution along astral microtubules and accumulated around the spindle pole, but they were not localized on the cleavage furrow (CF) sites. The depletion of the four COPII coatomer subunits, Sec16, or Sar1 that regulate COPII assembly resulted in multinucleated cell production after meiosis, suggesting that cytokinesis failed in both or either of the meiotic divisions. Although contractile actomyosin and anilloseptin rings were formed once plasma membrane ingression was initiated, they were frequently removed from the plasma membrane during furrowing. We explored the factors conveyed toward the CF sites in the membrane via COPII-mediated vesicles. DE-cadherin-containing vesicles were formed depending on Sar1 and were accumulated in the cleavage sites. Furthermore, COPII depletion inhibited de novo plasma membrane insertion. These findings suggest that COPII vesicles supply the factors essential for the anchoring and/or constriction of the contractile rings at cleavage sites during male meiosis in Drosophila.


Assuntos
Vesículas Revestidas pelo Complexo de Proteína do Envoltório , Citocinese , Proteínas de Drosophila , Meiose , Proteínas de Transporte Vesicular , Animais , Masculino , Caderinas/metabolismo , Membrana Celular/metabolismo , Vesículas Revestidas pelo Complexo de Proteína do Envoltório/metabolismo , Citocinese/fisiologia , Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Proteínas de Drosophila/metabolismo , Proteínas de Drosophila/genética , Retículo Endoplasmático/metabolismo , Complexo de Golgi/metabolismo , Meiose/fisiologia , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Proteínas Monoméricas de Ligação ao GTP/genética , Espermatócitos/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo
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