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1.
J Cancer Res Clin Oncol ; 145(10): 2413-2422, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31492983

RESUMO

PURPOSE: Polo-like kinase 4 (PLK4) is a serine/threonine protein kinase that regulates centriole duplication. PLK4 deregulation causes centrosome number abnormalities, mitotic defects, chromosomal instability and, consequently, tumorigenesis. Therefore, PLK4 has emerged as a therapeutic target for the treatment of multiple cancers. In this review, we summarize the critical role of centrosome amplification and PLK4 in cancer. We also highlight recent advances in the development of PLK4 inhibitors and discuss potential combination therapies for cancer. METHODS: The relevant literature from PubMed is reviewed in this article. The ClinicalTrials.gov database was searched for clinical trials related to the specific topic. RESULTS: PLK4 is aberrantly expressed in multiple cancers and has prognostic value. Targeting PLK4 with inhibitors suppresses tumor growth in vitro and in vivo. CONCLUSIONS: PLK4 plays an important role in centrosome amplification and tumor progression. PLK4 inhibitors used alone or in combination with other drugs have shown significant anticancer efficacy, suggesting a potential therapeutic strategy for cancer. The results of relevant clinical trials await evaluation.


Assuntos
Biomarcadores Tumorais , Neoplasias/etiologia , Neoplasias/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Centrossomo/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , Terapia de Alvo Molecular , Metástase Neoplásica , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Especificidade de Órgãos/genética , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Relação Estrutura-Atividade , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
2.
Results Probl Cell Differ ; 67: 17-25, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31435790

RESUMO

Acetylation is among the most prevalent posttranslational modifications in cells and regulates a number of physiological processes such as gene transcription, cell metabolism, and cell signaling. Although initially discovered on nuclear histones, many non-nuclear proteins have subsequently been found to be acetylated as well. The centrosome is the major microtubule-organizing center in most metazoans. Recent proteomic data indicate that a number of proteins in this subcellular compartment are acetylated. This review gives an overview of our current knowledge on protein acetylation at the centrosome and its functional relevance in organelle biology.


Assuntos
Centrossomo/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas/metabolismo , Acetilação , Animais , Histonas/metabolismo , Humanos , Proteômica
3.
Results Probl Cell Differ ; 67: 127-200, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31435795

RESUMO

For over a century, the centrosome has been an organelle more easily tracked than understood, and the study of its peregrinations within the cell remains a chief underpinning of its functional investigation. Increasing attention and new approaches have been brought to bear on mechanisms that control centrosome localization in the context of cleavage plane determination, ciliogenesis, directional migration, and immunological synapse formation, among other cellular and developmental processes. The Golgi complex, often linked with the centrosome, presents a contrasting case of a pleiomorphic organelle for which functional studies advanced somewhat more rapidly than positional tracking. However, Golgi orientation and distribution has emerged as an area of considerable interest with respect to polarized cellular function. This chapter will review our current understanding of the mechanism and significance of the positioning of these organelles.


Assuntos
Centrossomo/metabolismo , Complexo de Golgi/metabolismo
4.
Results Probl Cell Differ ; 67: 253-276, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31435799

RESUMO

'Does the geometric design of centrioles imply their function? Several principles of construction of a microscopically small device for locating the directions of signal sources in microscopic dimensions: it appears that the simplest and smallest device that is compatible with the scrambling influence of thermal fluctuations, as are demonstrated by Brownian motion, is a pair of cylinders oriented at right angles to each other. Centrioles locate the direction of hypothetical signals inside cells' (Albrecht-Buehler G, Cell Motil, 1:237-245; 1981).Despite a century of devoted efforts (articles on the centrosome always begin like this) its role remains vague and nebulous: does the centrosome suffer from bad press? Likely it does, it has an unfair image problem. It is dispensable in mitosis, but a fly zygote, artificially deprived of centrosomes, cannot start its development; its sophisticated architecture (200 protein types, highly conserved during evolution) constitutes an enigmatic puzzle; centrosome reduction in gametogenesis is a challenging brainteaser; its duplication cycle (only one centrosome per cell) is more complicated than chromosomes. Its striking geometric design (two ninefold symmetric orthogonal centrioles) shows an interesting correspondence with the requirements of a cellular compass: a reference system organizer based on a pair of orthogonal goniometers; through its two orthogonal centrioles, the centrosome may play the role of a cell geometry organizer: it can establish a finely tuned geometry, inherited and shared by all cells. Indeed, a geometrical and informational primary role for the centrosome has been ascertained in Caenorhabditis elegans zygote: the sperm centrosome locates its polarity factors. The centrosome, through its aster of microtubules, possesses all the characteristics necessary to operate as a biophysical geometric compass: it could recognize cargoes equipped with topogenic sequences and drive them precisely to where they are addressed (as hypothesized by Albrecht-Buehler nearly 40 years ago). Recently, this geometric role of the centrosome has been rediscovered by two important findings; in the Kupffer's vesicle (the laterality organ of zebrafish), chiral cilia orientation and rotational movement have been described: primary cilia, in left and right halves of the Kupffer's vesicle, are symmetrically oriented relative to the midline and rotate in reverse direction. In mice node (laterality organ) left and right perinodal cells can distinguish flow directionality through their primary cilia: primary cilium, ninefold symmetric, is strictly connected to the centrosome that is located immediately under it (basal body). Kupffer's vesicle histology and mirror behaviour of mice perinodal cells suggest primary cilia are enantiomeric geometric organelles. What is the meaning of the geometric design of centrioles and centrosomes? Does it imply their function?


Assuntos
Centrossomo/metabolismo , Animais , Centríolos/metabolismo , Cílios , Masculino , Espermatozoides/citologia , Peixe-Zebra
5.
Results Probl Cell Differ ; 67: 277-321, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31435800

RESUMO

The first 3 h of Drosophila melanogaster embryo development are exemplified by rapid nuclear divisions within a large syncytium, transforming the zygote to the cellular blastoderm after 13 successive cleavage divisions. As the syncytial embryo develops, it relies on centrosomes and cytoskeletal dynamics to transport nuclei, maintain uniform nuclear distribution throughout cleavage cycles, ensure generation of germ cells, and coordinate cellularization. For the sake of this review, we classify six early embryo stages that rely on processes coordinated by the centrosome and its regulation of the cytoskeleton. The first stage features migration of one of the female pronuclei toward the male pronucleus following maturation of the first embryonic centrosomes. Two subsequent stages distribute the nuclei first axially and then radially in the embryo. The remaining three stages involve centrosome-actin dynamics that control cortical plasma membrane morphogenesis. In this review, we highlight the dynamics of the centrosome and its role in controlling the six stages that culminate in the cellularization of the blastoderm embryo.


Assuntos
Centrossomo/metabolismo , Drosophila melanogaster/citologia , Drosophila melanogaster/embriologia , Embrião não Mamífero/citologia , Animais , Blastoderma , Núcleo Celular
6.
Results Probl Cell Differ ; 67: 413-440, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31435806

RESUMO

Centrosome amplification is a feature of multiple tumour types and has been postulated to contribute to both tumour initiation and tumour progression. This chapter focuses on the mechanisms by which an increase in centrosome number might lead to an increase or decrease in tumour progression and the role of proteins that regulate centrosome number in driving tumorigenesis.


Assuntos
Carcinogênese , Centrossomo/metabolismo , Neoplasias/patologia , Progressão da Doença , Humanos
7.
Nat Commun ; 10(1): 2356, 2019 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-31142743

RESUMO

Centrosomes control cell motility, polarity and migration that is thought to be mediated by their microtubule-organizing capacity. Here we demonstrate that WNT signalling drives a distinct form of non-directional cell motility that requires a key centrosome module, but not microtubules or centrosomes. Upon exosome mobilization of PCP-proteins, we show that DVL2 orchestrates recruitment of a CEP192-PLK4/AURKB complex to the cell cortex where PLK4/AURKB act redundantly to drive protrusive activity and cell motility. This is mediated by coordination of formin-dependent actin remodelling through displacement of cortically localized DAAM1 for DAAM2. Furthermore, abnormal expression of PLK4, AURKB and DAAM1 is associated with poor outcomes in breast and bladder cancers. Thus, a centrosomal module plays an atypical function in WNT signalling and actin nucleation that is critical for cancer cell motility and is associated with more aggressive cancers. These studies have broad implications in how contextual signalling controls distinct modes of cell migration.


Assuntos
Aurora Quinase B/metabolismo , Movimento Celular , Centrossomo/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Proteínas Desgrenhadas/metabolismo , Neoplasias/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Via de Sinalização Wnt , Actinas/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Neoplasias da Mama/metabolismo , Carcinoma de Células de Transição/metabolismo , Linhagem Celular Tumoral , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas dos Microfilamentos/metabolismo , Prognóstico , Mapas de Interação de Proteínas , Reação em Cadeia da Polimerase em Tempo Real , Neoplasias da Bexiga Urinária/metabolismo
8.
Nat Commun ; 10(1): 2129, 2019 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-31086189

RESUMO

De novo heterozygous missense variants in the γ-tubulin gene TUBG1 have been linked to human malformations of cortical development associated with intellectual disability and epilepsy. Here, we investigated through in-utero electroporation and in-vivo studies, how four of these variants affect cortical development. We show that TUBG1 mutants affect neuronal positioning, disrupting the locomotion of new-born neurons but without affecting progenitors' proliferation. We further demonstrate that pathogenic TUBG1 variants are linked to reduced microtubule dynamics but without major structural nor functional centrosome defects in subject-derived fibroblasts. Additionally, we developed a knock-in Tubg1Y92C/+ mouse model and assessed consequences of the mutation. Although centrosomal positioning in bipolar neurons is correct, they fail to initiate locomotion. Furthermore, Tubg1Y92C/+ animals show neuroanatomical and behavioral defects and increased epileptic cortical activity. We show that Tubg1Y92C/+ mice partially mimic the human phenotype and therefore represent a relevant model for further investigations of the physiopathology of cortical malformations.


Assuntos
Malformações do Desenvolvimento Cortical/genética , Microtúbulos/metabolismo , Neurogênese/genética , Neurônios/fisiologia , Tubulina (Proteína)/genética , Animais , Comportamento Animal , Movimento Celular/genética , Centrossomo/metabolismo , Córtex Cerebral/anormalidades , Córtex Cerebral/citologia , Córtex Cerebral/diagnóstico por imagem , Modelos Animais de Doenças , Embrião de Mamíferos , Epilepsia/genética , Feminino , Fibroblastos/citologia , Fibroblastos/metabolismo , Fibroblastos/ultraestrutura , Técnicas de Introdução de Genes , Predisposição Genética para Doença , Células HeLa , Humanos , Microscopia Intravital , Masculino , Camundongos , Camundongos Transgênicos , Microscopia Confocal , Microscopia Eletrônica , Microtúbulos/genética , Mutação de Sentido Incorreto
9.
Methods Cell Biol ; 151: 29-36, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30948013

RESUMO

I happen to have been trained in cell and developmental biology in the early 1970s, which was near the beginning of the explosive growth of the field of cell biology. The American Society for Cell Biology had been founded in 1960 and so the field was in its early days. Cell biology research was dominated by the use of the electron microscope and by protein biochemistry. Molecular biology and the use of genetics were in their infancy. When we track the path of discoveries in cell biology contributed by research using echinoderm eggs, we follow the development of new technologies in genetics, molecular biology, biochemistry and biophysics, bioengineering, and imaging. The changes in approaches and methods have led to many key discoveries in cell biology through the use of sea urchin, sand dollar and sea star eggs. These include the discovery of cyclin, cytoplasmic dynein, rho activation for cytokinesis, new membrane addition as a late event in cytokinesis, multiple kinesins playing multiple roles, how flagella beat, the dynamics of microtubules in the mitotic apparatus, control over centrosomes and cell cycle checkpoints, the process of nuclear envelope breakdown for cell division, the discovery of 1-methyl adenine (hormones) as the trigger for meiotic maturation, Ca++ transients controlling cell activation and exocytosis among others. What I hope to provide in this perspective is to highlight some of those wonderful discoveries as my own career evolved to contribute to the field.


Assuntos
Biologia Celular/história , Equinodermos/crescimento & desenvolvimento , Desenvolvimento Embrionário/genética , Óvulo/crescimento & desenvolvimento , Animais , Centrossomo/metabolismo , Citocinese/genética , Equinodermos/genética , Fertilização/genética , História do Século XX , História do Século XXI , Mitose/genética
10.
Methods Mol Biol ; 1953: 33-42, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30912014

RESUMO

Cellular models for siRNA and small molecule high-throughput screening have been widely used in the last decade to identify targets for drug discovery. As an example, we present a twofold readout approach based on cell viability and multipolar phenotype. To maximize the discovery of potential targets and at the same time reduce the number of false positives in our dataset, we have combined focused and rationally designed custom siRNA libraries with small molecule inhibitor libraries. Here we describe a cellular model for centrosome amplification as an example of how to design and perform a multiple readout/multiple screening strategy.


Assuntos
Descoberta de Drogas/métodos , Avaliação Pré-Clínica de Medicamentos/métodos , RNA Interferente Pequeno/genética , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Centrossomo/efeitos dos fármacos , Centrossomo/metabolismo , Biblioteca Gênica , Ensaios de Triagem em Larga Escala/métodos , Humanos , Interferência de RNA/efeitos dos fármacos
11.
Methods Mol Biol ; 1957: 271-289, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30919360

RESUMO

Primary cilia (PC) are microtubule-based organelles that behave like a cellular antenna controlling key signaling pathways during development and tissue homeostasis. The ciliary membrane is highly enriched for G protein-coupled receptors (GPCRs), and PC are a crucial signaling compartment for this large receptor family. Downstream effectors of GPCR signaling are also present in cilia, and evidence obtained by our labs and others demonstrated that ß-arrestin (ßarr) family members are differentially recruited to PC and have investigated the role of GPCR activation in this process. In this chapter, we provide methods based on fluorescence microscopy on fixed or live cells suitable for investigating targeting and recruitment of ßarrs at PC.


Assuntos
Corpos Basais/metabolismo , Centrossomo/metabolismo , Cílios/metabolismo , Microscopia de Fluorescência/métodos , beta-Arrestina 2/metabolismo , Animais , Corpos Basais/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular , Centrossomo/efeitos dos fármacos , Cílios/efeitos dos fármacos , DNA/metabolismo , Recuperação de Fluorescência Após Fotodegradação , Proteínas de Fluorescência Verde/metabolismo , Hipocampo/citologia , Humanos , Camundongos , Microtúbulos/efeitos dos fármacos , Microtúbulos/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Plasmídeos/metabolismo , Somatostatina/farmacologia
12.
Mol Biol Cell ; 30(7): 876-886, 2019 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-30840554

RESUMO

Across most sexually reproducing animals, centrosomes are provided to the oocyte through fertilization and must be positioned properly to establish the zygotic mitotic spindle. How centrosomes are positioned in space and time through the concerted action of key mitotic entry biochemical regulators, including protein phosphatase 2A (PP2A-B55/SUR-6), biophysical regulators, including dynein, and the nuclear lamina is unclear. Here, we uncover a role for PP2A-B55/SUR-6 in regulating centrosome separation. Mechanistically, PP2A-B55/SUR-6 regulates nuclear size before mitotic entry, in turn affecting nuclear envelope-based dynein density and motor capacity. Computational simulations predicted the requirement of PP2A-B55/SUR-6 regulation of nuclear size and nuclear-envelope dynein density for proper centrosome separation. Conversely, compromising nuclear lamina integrity led to centrosome detachment from the nuclear envelope and migration defects. Removal of PP2A-B55/SUR-6 and the nuclear lamina simultaneously further disrupted centrosome separation, leading to unseparated centrosome pairs dissociated from the nuclear envelope. Taking these combined results into consideration, we propose a model in which centrosomes migrate and are positioned through the concerted action of PP2A-B55/SUR-6-regulated nuclear envelope-based dynein pulling forces and centrosome-nuclear envelope tethering. Our results add critical precision to models of centrosome separation relative to the nucleus during spindle formation in cell division.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/fisiologia , Centrossomo/metabolismo , Proteína Fosfatase 2/metabolismo , Proteína Fosfatase 2/fisiologia , Animais , Caenorhabditis elegans/metabolismo , Ciclo Celular , Núcleo Celular/metabolismo , Centrossomo/fisiologia , Biologia Computacional , Simulação por Computador , Dineínas/metabolismo , Mitose/fisiologia , Membrana Nuclear/metabolismo , Lâmina Nuclear/metabolismo , Lâmina Nuclear/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Fuso Acromático/metabolismo
13.
Mol Biol Cell ; 30(10): 1160-1169, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30865554

RESUMO

The apicomplexan centrosome has a unique bipartite structure comprising an inner and outer core responsible for the nuclear cycle (mitosis) and budding cycles (cytokinesis), respectively. Although these two cores are always associated, they function independently to facilitate polyploid intermediates in the production of many progeny per replication round. Here, we describe the function of a large coiled-coil protein in Toxoplasma gondii, TgCep250, in connecting the two centrosomal cores and promoting their structural integrity. Throughout the cell cycle, TgCep250 localizes to the inner core but, associated with proteolytic processing, is also present on the outer core during the onset of cell division. In the absence of TgCep250, stray centrosome inner and outer core foci were observed. The detachment between centrosomal inner and outer cores was found in only one of the centrosomes during cell division, indicating distinct states of mother and daughter centrosomes. In mammals, Cep250 processing is required for centrosomal splitting and is mediated by Nek phopsphorylation. However, we show that neither the nonoverlapping spatiotemporal localization of TgNek1 and TgCep250 nor the distinct phenotypes upon their respective depletion support conservation of this mechanism in Toxoplasma. In conclusion, TgCep250 has a tethering function tailored to the unique bipartite centrosome in the Apicomplexa.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Centrossomo/metabolismo , Quinase 1 Relacionada a NIMA/metabolismo , Proteínas de Protozoários/metabolismo , Toxoplasma/metabolismo , Animais , Apicomplexa/metabolismo , Autoantígenos/metabolismo , Ciclo Celular/genética , Núcleo Celular/metabolismo , Citocinese/fisiologia , Replicação do DNA/fisiologia , Humanos , Mitose/fisiologia , Toxoplasma/citologia
14.
Dev Cell ; 48(5): 631-645.e6, 2019 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-30861375

RESUMO

Cell polarity is facilitated by a rearrangement of the actin cytoskeleton at the cell cortex. The program triggering the asymmetric remodeling of contractile actomyosin networks remains poorly understood. Here, we show that polarization of Caenorhabditis elegans zygotes is established through sequential downregulation of cortical actomyosin networks by the mitotic kinase, Aurora-A. Aurora-A accumulates around centrosomes to locally disrupt the actomyosin contractile activity at the proximal cortex, thereby promoting cortical flows during symmetry breaking. Aurora-A later mediates global disassembly of cortical actomyosin networks, which facilitates the initial polarization through suppression of centrosome-independent cortical flows. Translocation of Aurora-A from the cytoplasm to the cortex is sufficient to interfere with the cortical actomyosin networks independently of its roles in centrosome maturation and cell-cycle progression. We propose that Aurora-A activity serves as a centrosome-mediated cue that breaks symmetry in actomyosin contractile activity, and facilitates the initial polarization through global suppression of cortical actomyosin networks.


Assuntos
Citoesqueleto de Actina/metabolismo , Actomiosina/metabolismo , Centrossomo/metabolismo , Contração Muscular/fisiologia , Actomiosina/genética , Animais , Caenorhabditis elegans/citologia , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Polaridade Celular/fisiologia , Embrião não Mamífero/citologia , Microtúbulos/metabolismo , Fuso Acromático/genética
15.
PLoS Negl Trop Dis ; 13(3): e0007256, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30897087

RESUMO

Aurora kinases constitute a family of enzymes that play a key role during metazoan cells division, being involved in events like centrosome maturation and division, chromatin condensation, mitotic spindle assembly, control of kinetochore-microtubule attachments, and cytokinesis initiation. In this work, three Aurora kinase homologues were identified in Trypanosoma cruzi (TcAUK1, -2 and -3), a protozoan parasite of the Kinetoplastida Class. The genomic organization of these enzymes was fully analyzed, demonstrating that TcAUK1 is a single-copy gene, TcAUK2 coding sequence is present in two different forms (short and long) and TcAUK3 is a multi-copy gene. The three TcAUK genes are actively expressed in the different life cycle forms of T. cruzi (amastigotes, trypomastigotes and epimastigotes). TcAUK1 showed a changing localization along the cell cycle of the proliferating epimastigote form: at interphase it is located at the extremes of the kinetoplast while in mitosis it is detected at the cell nucleus, in close association with the mitotic spindle. Overexpression of TcAUK1 in epimastigotes leaded to a delay in the G2/M phases of the cell cycle due a retarded beginning of kinetoplast duplication. By immunofluorescence, we found that when it was overexpressed TcAUK1 lost its localization at the extremes of the kinetoplast during interphase, being observed inside the cell nucleus throughout the entire cell cycle. In summary, TcAUK1 appears to be a functional homologue of human Aurora B kinase, as it is related to mitotic spindle assembling and chromosome segregation. Moreover, TcAUK1 also seems to play a role during the initiation of kinetoplast duplication, a novel role described for this protein.


Assuntos
Aurora Quinases/metabolismo , Estágios do Ciclo de Vida , Mitocôndrias/fisiologia , Trypanosoma cruzi/enzimologia , Aurora Quinases/genética , Núcleo Celular/metabolismo , Centrossomo/metabolismo , Segregação de Cromossomos , Citocinese , Humanos , Mitose , Proteínas de Protozoários/genética , Proteínas de Protozoários/metabolismo , Fuso Acromático/metabolismo , Trypanosoma cruzi/genética , Trypanosoma cruzi/crescimento & desenvolvimento , Trypanosoma cruzi/fisiologia
16.
Mol Biol Cell ; 30(8): 992-1007, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30726162

RESUMO

Cell division is critical for development, organ growth, and tissue repair. The later stages of cell division include the formation of the microtubule (MT)-rich central spindle in anaphase, which is required to properly define the cell equator, guide the assembly of the acto-myosin contractile ring and ultimately ensure complete separation and isolation of the two daughter cells via abscission. Much is known about the molecular machinery that forms the central spindle, including proteins needed to generate the antiparallel overlapping interzonal MTs. One critical protein that has garnered great attention is the protein regulator of cytokinesis 1, or Fascetto (Feo) in Drosophila, which forms a homodimer to cross-link interzonal MTs, ensuring proper central spindle formation and cytokinesis. Here, we report on a new direct protein interactor and regulator of Feo we named Feo interacting protein (FIP). Loss of FIP results in a reduction in Feo localization, rapid disassembly of interzonal MTs, and several defects related to cytokinesis failure, including polyploidization of neural stem cells. Simultaneous reduction in Feo and FIP results in very large, tumorlike DNA-filled masses in the brain that contain hundreds of centrosomes. In aggregate, our data show that FIP acts directly on Feo to ensure fully accurate cell division.


Assuntos
Proteínas de Drosophila/antagonistas & inibidores , Proteínas de Drosophila/metabolismo , Proteínas Associadas aos Microtúbulos/antagonistas & inibidores , Proteínas Associadas aos Microtúbulos/metabolismo , Anáfase/fisiologia , Animais , Divisão Celular/fisiologia , Centrossomo/metabolismo , Citocinese , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/metabolismo , Desenvolvimento Embrionário , Proteínas Associadas aos Microtúbulos/fisiologia , Microtúbulos/metabolismo , Miosinas/metabolismo , Domínios e Motivos de Interação entre Proteínas/fisiologia , Fuso Acromático/metabolismo
17.
Mol Biol Cell ; 30(10): 1230-1244, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30811267

RESUMO

The centrosome, composed of two centrioles surrounded by pericentriolar material, is the cell's central microtubule-organizing center. Centrosome duplication is coupled with the cell cycle such that centrosomes duplicate once in S phase. Loss of such coupling produces supernumerary centrosomes, a condition called centrosome amplification (CA). CA promotes cell invasion and chromosome instability, two hallmarks of cancer. We examined the contribution of centriole overduplication to CA and the consequences for genomic stability in breast cancer cells. CEP135, a centriole assembly protein, is dysregulated in some breast cancers. We previously identified a short isoform of CEP135, CEP135mini, that represses centriole duplication. Here, we show that the relative level of full-length CEP135 (CEP135full) to CEP135mini (the CEP135full:mini ratio) is increased in breast cancer cell lines with high CA. Inducing expression of CEP135full in breast cancer cells increases the frequency of CA, multipolar spindles, anaphase-lagging chromosomes, and micronuclei. Conversely, inducing expression of CEP135mini reduces centrosome number. The differential expression of the CEP135 isoforms in vivo is generated by alternative polyadenylation. Directed genetic mutations near the CEP135mini alternative polyadenylation signal reduces the CEP135full:mini ratio and decreases CA. We conclude that dysregulation of CEP135 isoforms promotes centriole overduplication and contributes to chromosome segregation errors in breast cancer cells.


Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Proteínas de Transporte/metabolismo , Centrossomo/metabolismo , Aneuploidia , Proteínas de Transporte/genética , Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Centríolos/metabolismo , Instabilidade Cromossômica , Segregação de Cromossomos/genética , Segregação de Cromossomos/fisiologia , Feminino , Instabilidade Genômica , Humanos , Mitose/fisiologia , Isoformas de Proteínas , Fase S/fisiologia
18.
Nature ; 567(7746): 113-117, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30787442

RESUMO

The expansion of brain size is accompanied by a relative enlargement of the subventricular zone during development. Epithelial-like neural stem cells divide in the ventricular zone at the ventricles of the embryonic brain, self-renew and generate basal progenitors1 that delaminate and settle in the subventricular zone in enlarged brain regions2. The length of time that cells stay in the subventricular zone is essential for controlling further amplification and fate determination. Here we show that the interphase centrosome protein AKNA has a key role in this process. AKNA localizes at the subdistal appendages of the mother centriole in specific subtypes of neural stem cells, and in almost all basal progenitors. This protein is necessary and sufficient to organize centrosomal microtubules, and promote their nucleation and growth. These features of AKNA are important for mediating the delamination process in the formation of the subventricular zone. Moreover, AKNA regulates the exit from the subventricular zone, which reveals the pivotal role of centrosomal microtubule organization in enabling cells to both enter and remain in the subventricular zone. The epithelial-to-mesenchymal transition is also regulated by AKNA in other epithelial cells, demonstrating its general importance for the control of cell delamination.


Assuntos
Centrossomo/metabolismo , Proteínas de Ligação a DNA/metabolismo , Ventrículos Laterais/citologia , Ventrículos Laterais/embriologia , Microtúbulos/metabolismo , Neurogênese , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Animais , Movimento Celular , Células Cultivadas , Células Epiteliais/metabolismo , Transição Epitelial-Mesenquimal , Humanos , Junções Intercelulares/metabolismo , Interfase , Ventrículos Laterais/anatomia & histologia , Glândulas Mamárias Animais/citologia , Camundongos , Tamanho do Órgão , Organoides/citologia
19.
Phys Rev E ; 99(1-1): 012409, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30780383

RESUMO

During the interphase in mammalian cells, the position of the centrosome is actively maintained at a small but finite distance away from the nucleus. The perinuclear positioning of the centrosome is crucial for cellular trafficking and progression into mitosis. Although the literature suggests that the contributions of the microtubule-associated forces bring the centrosome to the center of the cell, the position of the centrosome was merely investigated in the absence of the nucleus. Upon performing a coarse-grained simulation study with mathematical analysis, we show that the combined effect of the forces due to the cell cortex and the nucleus facilitate the centrosome positioning. Our study also demonstrates that in the absence of nucleus-based forces, the centrosome collapses on the nucleus due to cortical forces. Depending upon the magnitudes of the cortical forces and the nucleus-based forces, the centrosome appears to stay at various distances away from the nucleus. Such null force regions are found to be stable as well as unstable fixed points. This study uncovers a set of redundant schemes that the cell may adopt to produce the required cortical and nucleus-based forces stabilizing the centrosome at a finite distance away from the nucleus.


Assuntos
Centrossomo/metabolismo , Interfase , Modelos Biológicos , Fenômenos Biomecânicos , Membrana Celular/metabolismo , Núcleo Celular/metabolismo
20.
Nat Commun ; 10(1): 931, 2019 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-30804344

RESUMO

Centriole duplication occurs once per cell cycle to ensure robust formation of bipolar spindles and chromosome segregation. Each newly-formed daughter centriole remains connected to its mother centriole until late mitosis. The disengagement of the centriole pair is required for centriole duplication. However, the mechanisms underlying centriole engagement remain poorly understood. Here, we show that Cep57 is required for pericentriolar material (PCM) organization that regulates centriole engagement. Depletion of Cep57 causes PCM disorganization and precocious centriole disengagement during mitosis. The disengaged daughter centrioles acquire ectopic microtubule-organizing-center activity, which results in chromosome mis-segregation. Similar defects are observed in mosaic variegated aneuploidy syndrome patient cells with cep57 mutations. We also find that Cep57 binds to the well-conserved PACT domain of pericentrin. Microcephaly osteodysplastic primordial dwarfism disease pericentrin mutations impair the Cep57-pericentrin interaction and lead to PCM disorganization. Together, our work demonstrates that Cep57 provides a critical interface between the centriole core and PCM.


Assuntos
Antígenos/metabolismo , Centríolos/metabolismo , Centrossomo/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Nucleares/metabolismo , Antígenos/química , Antígenos/genética , Centríolos/química , Centríolos/genética , Células HeLa , Humanos , Proteínas Associadas aos Microtúbulos/química , Proteínas Associadas aos Microtúbulos/genética , Mitose , Mutação , Proteínas Nucleares/química , Proteínas Nucleares/genética , Ligação Proteica , Domínios Proteicos
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