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1.
J Cell Sci ; 137(18)2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-39155850

RESUMEN

His domain protein tyrosine phosphatase (HD-PTP; also known as PTPN23) facilitates function of the endosomal sorting complexes required for transport (ESCRTs) during multivesicular body (MVB) formation. To uncover its role in physiological homeostasis, embryonic lethality caused by a complete lack of HD-PTP was bypassed through generation of hypomorphic mice expressing reduced protein, resulting in animals that are viable into adulthood. These mice exhibited marked lipodystrophy and decreased receptor-mediated signaling within white adipose tissue (WAT), involving multiple prominent pathways including RAS/MAPK, phosphoinositide 3-kinase (PI3K)/AKT and receptor tyrosine kinases (RTKs), such as EGFR. EGFR signaling was dissected in vitro to assess the nature of defective signaling, revealing decreased trans-autophosphorylation and downstream effector activation, despite normal EGF binding. This corresponds to decreased plasma membrane cholesterol and increased lysosomal cholesterol, likely resulting from defective endosomal maturation necessary for cholesterol trafficking and homeostasis. The ESCRT components Vps4 and Hrs have previously been implicated in cholesterol homeostasis; thus, these findings expand knowledge on which ESCRT subunits are involved in cholesterol homeostasis and highlight a non-canonical role for HD-PTP in signal regulation and adipose tissue homeostasis.


Asunto(s)
Complejos de Clasificación Endosomal Requeridos para el Transporte , Homeostasis , Lipodistrofia , Proteínas Tirosina Fosfatasas no Receptoras , Transducción de Señal , Animales , Ratones , Lipodistrofia/metabolismo , Lipodistrofia/genética , Lipodistrofia/patología , Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , Complejos de Clasificación Endosomal Requeridos para el Transporte/genética , Proteínas Tirosina Fosfatasas no Receptoras/metabolismo , Proteínas Tirosina Fosfatasas no Receptoras/genética , Colesterol/metabolismo , Metabolismo de los Lípidos , Receptores ErbB/metabolismo , Receptores ErbB/genética , Humanos , Tejido Adiposo Blanco/metabolismo
2.
Nat Commun ; 14(1): 2983, 2023 05 24.
Artículo en Inglés | MEDLINE | ID: mdl-37225693

RESUMEN

PTEN is a multifaceted tumor suppressor that is highly sensitive to alterations in expression or function. The PTEN C-tail domain, which is rich in phosphorylation sites, has been implicated in PTEN stability, localization, catalytic activity, and protein interactions, but its role in tumorigenesis remains unclear. To address this, we utilized several mouse strains with nonlethal C-tail mutations. Mice homozygous for a deletion that includes S370, S380, T382 and T383 contain low PTEN levels and hyperactive AKT but are not tumor prone. Analysis of mice containing nonphosphorylatable or phosphomimetic versions of S380, a residue hyperphosphorylated in human gastric cancers, reveal that PTEN stability and ability to inhibit PI3K-AKT depends on dynamic phosphorylation-dephosphorylation of this residue. While phosphomimetic S380 drives neoplastic growth in prostate by promoting nuclear accumulation of ß-catenin, nonphosphorylatable S380 is not tumorigenic. These data suggest that C-tail hyperphosphorylation creates oncogenic PTEN and is a potential target for anti-cancer therapy.


Asunto(s)
Carcinogénesis , Fosfohidrolasa PTEN , Animales , Humanos , Masculino , Ratones , Carcinogénesis/genética , Homocigoto , Mutación , Fosfatidilinositol 3-Quinasas , Proteínas Proto-Oncogénicas c-akt , Fosfohidrolasa PTEN/genética , Fosforilación
3.
Nat Commun ; 13(1): 3722, 2022 06 28.
Artículo en Inglés | MEDLINE | ID: mdl-35764649

RESUMEN

Super-enhancers regulate genes with important functions in processes that are cell type-specific or define cell identity. Mouse embryonic fibroblasts establish 40 senescence-associated super-enhancers regardless of how they become senescent, with 50 activated genes located in the vicinity of these enhancers. Here we show, through gene knockdown and analysis of three core biological properties of senescent cells that a relatively large number of senescence-associated super-enhancer-regulated genes promote survival of senescent mouse embryonic fibroblasts. Of these, Mdm2, Rnase4, and Ang act by suppressing p53-mediated apoptosis through various mechanisms that are also engaged in response to DNA damage. MDM2 and RNASE4 transcription is also elevated in human senescent fibroblasts to restrain p53 and promote survival. These insights identify key survival mechanisms of senescent cells and provide molecular entry points for the development of targeted therapeutics that eliminate senescent cells at sites of pathology.


Asunto(s)
Fibroblastos , Proteína p53 Supresora de Tumor , Animales , Apoptosis/genética , Senescencia Celular/genética , Daño del ADN , Fibroblastos/fisiología , Ratones , Proteína p53 Supresora de Tumor/genética
4.
Science ; 374(6567): eabb3420, 2021 Oct 29.
Artículo en Inglés | MEDLINE | ID: mdl-34709885

RESUMEN

Immune cells identify and destroy damaged cells to prevent them from causing cancer or other pathologies by mechanisms that remain poorly understood. Here, we report that the cell-cycle inhibitor p21 places cells under immunosurveillance to establish a biological timer mechanism that controls cell fate. p21 activates retinoblastoma protein (Rb)­dependent transcription at select gene promoters to generate a complex bioactive secretome, termed p21-activated secretory phenotype (PASP). The PASP includes the chemokine CXCL14, which promptly attracts macrophages. These macrophages disengage if cells normalize p21 within 4 days, but if p21 induction persists, they polarize toward an M1 phenotype and lymphocytes mount a cytotoxic T cell response to eliminate target cells, including preneoplastic cells. Thus, p21 concurrently induces proliferative arrest and immunosurveillance of cells under duress.


Asunto(s)
Senescencia Celular , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Vigilancia Inmunológica , Animales , Puntos de Control del Ciclo Celular , Línea Celular , Quimiocinas CXC/metabolismo , Inhibidor p16 de la Quinasa Dependiente de Ciclina/genética , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Genes ras , Hepatocitos/inmunología , Hepatocitos/metabolismo , Humanos , Macrófagos/inmunología , Macrófagos/metabolismo , Ratones , Ratones Transgénicos , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Proteína de Retinoblastoma/metabolismo , Estrés Fisiológico , Linfocitos T Citotóxicos/inmunología , Transcripción Genética
6.
J Clin Invest ; 130(1): 171-188, 2020 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-31738183

RESUMEN

Mosaic-variegated aneuploidy (MVA) syndrome is a rare childhood disorder characterized by biallelic BUBR1, CEP57, or TRIP13 aberrations; increased chromosome missegregation; and a broad spectrum of clinical features, including various cancers, congenital defects, and progeroid pathologies. To investigate the mechanisms underlying this disorder and its phenotypic heterogeneity, we mimicked the BUBR1L1012P mutation in mice (BubR1L1002P) and combined it with 2 other MVA variants, BUBR1X753 and BUBR1H, generating a truncated protein and low amounts of wild-type protein, respectively. Whereas BubR1X753/L1002P and BubR1H/X753 mice died prematurely, BubR1H/L1002P mice were viable and exhibited many MVA features, including cancer predisposition and various progeroid phenotypes, such as short lifespan, dwarfism, lipodystrophy, sarcopenia, and low cardiac stress tolerance. Strikingly, although these mice had a reduction in total BUBR1 and spectrum of MVA phenotypes similar to that of BubR1H/H mice, several progeroid pathologies were attenuated in severity, which in skeletal muscle coincided with reduced senescence-associated secretory phenotype complexity. Additionally, mice carrying monoallelic BubR1 mutations were prone to select MVA-related pathologies later in life, with predisposition to sarcopenia correlating with mTORC1 hyperactivity. Together, these data demonstrate that BUBR1 allelic effects beyond protein level and aneuploidy contribute to disease heterogeneity in both MVA patients and heterozygous carriers of MVA mutations.


Asunto(s)
Alelos , Proteínas de Ciclo Celular/genética , Trastornos de los Cromosomas/genética , Progeria/genética , Proteínas Serina-Treonina Quinasas/genética , Envejecimiento , Animales , Neoplasias Pulmonares/etiología , Ratones , Ratones Endogámicos C57BL , Mitosis , Mosaicismo , Mutación , Fenotipo
7.
Nat Cancer ; 1(10): 1010-1024, 2020 10.
Artículo en Inglés | MEDLINE | ID: mdl-34841254

RESUMEN

FoxM1 activates genes that regulate S-G2-M cell-cycle progression and, when overexpressed, is associated with poor clinical outcome in multiple cancers. Here we identify FoxM1 as a tumor suppressor in mice that, through its N-terminal domain, binds to and inhibits Ect2 to limit the activity of RhoA GTPase and its effector mDia1, a catalyst of cortical actin nucleation. FoxM1 insufficiency impedes centrosome movement through excessive cortical actin polymerization, thereby causing the formation of non-perpendicular mitotic spindles that missegregate chromosomes and drive tumorigenesis in mice. Importantly, low FOXM1 expression correlates with RhoA GTPase hyperactivity in multiple human cancer types, indicating that suppression of the newly discovered Ect2-RhoAmDia1 oncogenic axis by FoxM1 is clinically relevant. Furthermore, by dissecting the domain requirements through which FoxM1 inhibits Ect2 GEF activity, we provide mechanistic insight for the development of pharmacological approaches that target protumorigenic RhoA activity.


Asunto(s)
Actinas , Proteína Forkhead Box M1/metabolismo , Neoplasias , Actinas/metabolismo , Animales , GTP Fosfohidrolasas , Ratones , Neoplasias/genética , Transducción de Señal
8.
Gastroenterology ; 157(1): 210-226.e12, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-30878468

RESUMEN

BACKGROUND & AIMS: The CCNE1 locus, which encodes cyclin E1, is amplified in many types of cancer cells and is activated in hepatocellular carcinomas (HCCs) from patients infected with hepatitis B virus or adeno-associated virus type 2, due to integration of the virus nearby. We investigated cell-cycle and oncogenic effects of cyclin E1 overexpression in tissues of mice. METHODS: We generated mice with doxycycline-inducible expression of Ccne1 (Ccne1T mice) and activated overexpression of cyclin E1 from age 3 weeks onward. At 14 months of age, livers were collected from mice that overexpress cyclin E1 and nontransgenic mice (controls) and analyzed for tumor burden and by histology. Mouse embryonic fibroblasts (MEFs) and hepatocytes from Ccne1T and control mice were analyzed to determine the extent to which cyclin E1 overexpression perturbs S-phase entry, DNA replication, and numbers and structures of chromosomes. Tissues from 4-month-old Ccne1T and control mice (at that age were free of tumors) were analyzed for chromosome alterations, to investigate the mechanisms by which cyclin E1 predisposes hepatocytes to transformation. RESULTS: Ccne1T mice developed more hepatocellular adenomas and HCCs than control mice. Tumors developed only in livers of Ccne1T mice, despite high levels of cyclin E1 in other tissues. Ccne1T MEFs had defects that promoted chromosome missegregation and aneuploidy, including incomplete replication of DNA, centrosome amplification, and formation of nonperpendicular mitotic spindles. Whereas Ccne1T mice accumulated near-diploid aneuploid cells in multiple tissues and organs, polyploidization was observed only in hepatocytes, with losses and gains of whole chromosomes, DNA damage, and oxidative stress. CONCLUSIONS: Livers, but not other tissues of mice with inducible overexpression of cyclin E1, develop tumors. More hepatocytes from the cyclin E1-overexpressing mice were polyploid than from control mice, and had losses or gains of whole chromosomes, DNA damage, and oxidative stress; all of these have been observed in human HCC cells. The increased risk of HCC in patients with hepatitis B virus or adeno-associated virus type 2 infection might involve activation of cyclin E1 and its effects on chromosomes and genomes of liver cells.


Asunto(s)
Adenoma de Células Hepáticas/genética , Carcinoma Hepatocelular/genética , Inestabilidad Cromosómica/genética , Ciclina E/genética , Neoplasias Hepáticas/genética , Hígado/metabolismo , Proteínas Oncogénicas/genética , Adenoma de Células Hepáticas/patología , Adenoma de Células Hepáticas/virología , Animales , Carcinoma Hepatocelular/patología , Carcinoma Hepatocelular/virología , Estructuras Cromosómicas , Daño del ADN/genética , Replicación del ADN , Dependovirus , Fibroblastos , Hepatitis B Crónica , Hepatocitos , Hígado/patología , Neoplasias Hepáticas/patología , Neoplasias Hepáticas/virología , Neoplasias Hepáticas Experimentales/genética , Neoplasias Hepáticas Experimentales/patología , Ratones , Estrés Oxidativo/genética , Infecciones por Parvoviridae , Parvovirinae , Poliploidía , Puntos de Control de la Fase S del Ciclo Celular
9.
J Clin Invest ; 128(8): 3517-3534, 2018 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-30035751

RESUMEN

A homozygous truncating frameshift mutation in CEP57 (CEP57T/T) has been identified in a subset of mosaic-variegated aneuploidy (MVA) patients; however, the physiological roles of the centrosome-associated protein CEP57 that contribute to disease are unknown. To investigate these, we have generated a mouse model mimicking this disease mutation. Cep57T/T mice died within 24 hours after birth with short, curly tails and severely impaired vertebral ossification. Osteoblasts in lumbosacral vertebrae of Cep57T/T mice were deficient for Fgf2, a Cep57 binding partner implicated in diverse biological processes, including bone formation. Furthermore, a broad spectrum of tissues of Cep57T/T mice had severe aneuploidy at birth, consistent with the MVA patient phenotype. Cep57T/T mouse embryonic fibroblasts and patient-derived skin fibroblasts failed to undergo centrosome maturation in G2 phase, causing premature centriole disjunction, centrosome amplification, aberrant spindle formation, and high rates of chromosome missegregation. Mice heterozygous for the truncating frameshift mutation or a Cep57-null allele were overtly indistinguishable from WT mice despite reduced Cep57 protein levels, yet prone to aneuploidization and cancer, with tumors lacking evidence for loss of heterozygosity. This study identifies Cep57 as a haploinsufficient tumor suppressor with biologically diverse roles in centrosome maturation and Fgf2-mediated bone formation.


Asunto(s)
Proteínas Portadoras/metabolismo , Trastornos de los Cromosomas/metabolismo , Mutación del Sistema de Lectura , Haploinsuficiencia , Neoplasias/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Proteínas Portadoras/genética , Proteínas de Ciclo Celular , Centrosoma/metabolismo , Centrosoma/patología , Trastornos de los Cromosomas/genética , Trastornos de los Cromosomas/patología , Cromosomas de los Mamíferos/genética , Cromosomas de los Mamíferos/metabolismo , Factor 2 de Crecimiento de Fibroblastos/genética , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Humanos , Ratones , Ratones Mutantes , Mosaicismo , Neoplasias/genética , Neoplasias/patología , Proteínas Supresoras de Tumor/genética
10.
Nat Commun ; 9(1): 2736, 2018 07 16.
Artículo en Inglés | MEDLINE | ID: mdl-30013081

RESUMEN

Cells respond to cytotoxic DNA double-strand breaks by recruiting repair proteins to the damaged site. Phosphorylation of the histone variant H2AX at S139 and Y142 modulate its interaction with downstream DNA repair proteins and their recruitment to DNA lesions. Here we report ATM-dependent ZNF506 localization to the lesion through MDC1 following DNA damage. ZNF506, in turn, recruits the protein phosphatase EYA, resulting in dephosphorylation of H2AX at Y142, which further facilitates the recruitment of MDC1 and other downstream repair factors. Thus, ZNF506 regulates the early dynamic signaling in the DNA damage response (DDR) pathway and controls progressive downstream signal amplification. Cells lacking ZNF506 or harboring mutations found in cancer patient samples are more sensitive to radiation, offering a potential new therapeutic option for cancers with mutations in this pathway. Taken together, these results demonstrate how the DDR pathway is orchestrated by ZNF506 to maintain genomic integrity.


Asunto(s)
Reparación del ADN , Retroalimentación Fisiológica , Regulación Leucémica de la Expresión Génica , Histonas/genética , Factores de Transcripción de Tipo Kruppel/genética , Leucemia Prolinfocítica de Células T/genética , Proteínas Represoras/genética , Proteínas Adaptadoras Transductoras de Señales , Animales , Linfocitos B/metabolismo , Linfocitos B/patología , Proteínas de Ciclo Celular , Línea Celular Tumoral , Daño del ADN , Células Epiteliales/citología , Células Epiteliales/metabolismo , Células HEK293 , Histonas/metabolismo , Humanos , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Factores de Transcripción de Tipo Kruppel/metabolismo , Leucemia Prolinfocítica de Células T/metabolismo , Leucemia Prolinfocítica de Células T/mortalidad , Leucemia Prolinfocítica de Células T/patología , Ratones , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Osteoblastos/citología , Osteoblastos/metabolismo , Fosforilación , Proteínas Tirosina Fosfatasas/genética , Proteínas Tirosina Fosfatasas/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Represoras/metabolismo , Transducción de Señal , Análisis de Supervivencia , Transactivadores/genética , Transactivadores/metabolismo
11.
Nat Cell Biol ; 20(4): 455-464, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29581593

RESUMEN

Cells respond to cytotoxic DNA double-strand breaks (DSBs) by recruiting DNA repair proteins to the damaged site. This recruitment is dependent on ubiquitylation of adjacent chromatin areas by E3 ubiquitin ligases such as RNF8 and RNF168, which are recruited sequentially to the DSBs. However, it is unclear what dictates the sequential order and recruits RNF168 to the DNA lesion. Here, we reveal that L3MBTL2 (lethal(3)malignant brain tumour-like protein 2) is the missing link between RNF8 and RNF168. We found that L3MBTL2 is recruited by MDC1 and subsequently ubiquitylated by RNF8. Ubiquitylated L3MBTL2, in turn, facilitates recruitment of RNF168 to the DNA lesion and promotes DNA DSB repair. These results identify L3MBTL2 as a key target of RNF8 following DNA damage and demonstrates how the DNA damage response pathway is orchestrated by ubiquitin signalling.


Asunto(s)
Roturas del ADN de Doble Cadena , Reparación del ADN , Proteínas de Unión al ADN/metabolismo , Proteínas Nucleares/metabolismo , Osteosarcoma/metabolismo , Transducción de Señal , Factores de Transcripción/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Proteínas Adaptadoras Transductoras de Señales , Proteínas de la Ataxia Telangiectasia Mutada/genética , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Proteínas de Ciclo Celular , Proteínas de Unión al ADN/genética , Células HEK293 , Humanos , Proteínas Nucleares/genética , Osteosarcoma/genética , Osteosarcoma/patología , Fosforilación , Transporte de Proteínas , Transactivadores/genética , Transactivadores/metabolismo , Factores de Transcripción/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitinación
12.
Science ; 353(6307): 1549-1552, 2016 09 30.
Artículo en Inglés | MEDLINE | ID: mdl-27708105

RESUMEN

Cyclin A2 activates the cyclin-dependent kinases Cdk1 and Cdk2 and is expressed at elevated levels from S phase until early mitosis. We found that mutant mice that cannot elevate cyclin A2 are chromosomally unstable and tumor-prone. Underlying the chromosomal instability is a failure to up-regulate the meiotic recombination 11 (Mre11) nuclease in S phase, which leads to impaired resolution of stalled replication forks, insufficient repair of double-stranded DNA breaks, and improper segregation of sister chromosomes. Unexpectedly, cyclin A2 controlled Mre11 abundance through a C-terminal RNA binding domain that selectively and directly binds Mre11 transcripts to mediate polysome loading and translation. These data reveal cyclin A2 as a mechanistically diverse regulator of DNA replication combining multifaceted kinase-dependent functions with a kinase-independent, RNA binding-dependent role that ensures adequate repair of common replication errors.


Asunto(s)
Inestabilidad Cromosómica , Ciclina A2/metabolismo , Enzimas Reparadoras del ADN/genética , Replicación del ADN/genética , Proteínas de Unión al ADN/genética , Regulación de la Expresión Génica , Biosíntesis de Proteínas/genética , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/metabolismo , Animales , Proteína Quinasa CDC2/metabolismo , Centrosoma/metabolismo , Ciclina A2/genética , Roturas del ADN de Doble Cadena , Reparación del ADN , Humanos , Cinesinas/metabolismo , Proteína Homóloga de MRE11 , Meiosis/genética , Ratones , Ratones Mutantes , Mitosis/genética , ARN Mensajero/genética , Proteínas de Unión al ARN/genética , Fase S/genética
13.
Elife ; 52016 08 16.
Artículo en Inglés | MEDLINE | ID: mdl-27528194

RESUMEN

BubR1 is a key component of the spindle assembly checkpoint (SAC). Mutations that reduce BubR1 abundance cause aneuploidization and tumorigenesis in humans and mice, whereas BubR1 overexpression protects against these. However, how supranormal BubR1 expression exerts these beneficial physiological impacts is poorly understood. Here, we used Bub1b mutant transgenic mice to explore the role of the amino-terminal (BubR1(N)) and internal (BubR1(I)) Cdc20-binding domains of BubR1 in preventing aneuploidy and safeguarding against cancer. BubR1(N) was necessary, but not sufficient to protect against aneuploidy and cancer. In contrast, BubR1 lacking the internal Cdc20-binding domain provided protection against both, which coincided with improved microtubule-kinetochore attachment error correction and SAC activity. Maximal SAC reinforcement occurred when both the Phe- and D-box of BubR1(I) were disrupted. Thus, while under- or overexpression of most mitotic regulators impairs chromosome segregation fidelity, certain manipulations of BubR1 can positively impact this process and therefore be therapeutically exploited.


Asunto(s)
Aneuploidia , Carcinogénesis , Proteínas Serina-Treonina Quinasas/metabolismo , Animales , Humanos , Ratones Transgénicos
14.
Nat Cell Biol ; 18(7): 814-21, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27240320

RESUMEN

Phosphatase and tensin homologue (Pten) suppresses neoplastic growth by negatively regulating PI(3)K signalling through its phosphatase activity. To gain insight into the actions of non-catalytic Pten domains in normal physiological processes and tumorigenesis, we engineered mice lacking the PDZ-binding domain (PDZ-BD). Here, we show that the PDZ-BD regulates centrosome movement and that its heterozygous or homozygous deletion promotes aneuploidy and tumour formation. We found that Pten is recruited to pre-mitotic centrosomes in a Plk1-dependent fashion to create a docking site for protein complexes containing the PDZ-domain-containing protein Dlg1 (also known as Sap97) and Eg5 (also known as Kif11), a kinesin essential for centrosome movement and bipolar spindle formation. Docking of Dlg1-Eg5 complexes to Pten depended on Eg5 phosphorylation by the Nek9-Nek6 mitotic kinase cascade and Cdk1. PDZ-BD deletion or Dlg1 ablation impaired loading of Eg5 onto centrosomes and spindle pole motility, yielding asymmetrical spindles that are prone to chromosome missegregation. Collectively, these data demonstrate that Pten, through the Dlg1-binding ability of its PDZ-BD, accumulates phosphorylated Eg5 at duplicated centrosomes to establish symmetrical bipolar spindles that properly segregate chromosomes, and suggest that this function contributes to tumour suppression.


Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Centrosoma/metabolismo , Cinesinas/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Fosfohidrolasa PTEN/metabolismo , Polos del Huso/metabolismo , Animales , Ciclo Celular/genética , Ciclo Celular/fisiología , Homólogo 1 de la Proteína Discs Large , Humanos , Ratones , Mitosis/genética , Fosfohidrolasa PTEN/genética , Proteínas Asociadas a SAP90-PSD95
15.
Nature ; 530(7589): 184-9, 2016 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-26840489

RESUMEN

Cellular senescence, a stress-induced irreversible growth arrest often characterized by expression of p16(Ink4a) (encoded by the Ink4a/Arf locus, also known as Cdkn2a) and a distinctive secretory phenotype, prevents the proliferation of preneoplastic cells and has beneficial roles in tissue remodelling during embryogenesis and wound healing. Senescent cells accumulate in various tissues and organs over time, and have been speculated to have a role in ageing. To explore the physiological relevance and consequences of naturally occurring senescent cells, here we use a previously established transgene, INK-ATTAC, to induce apoptosis in p16(Ink4a)-expressing cells of wild-type mice by injection of AP20187 twice a week starting at one year of age. We show that compared to vehicle alone, AP20187 treatment extended median lifespan in both male and female mice of two distinct genetic backgrounds. The clearance of p16(Ink4a)-positive cells delayed tumorigenesis and attenuated age-related deterioration of several organs without apparent side effects, including kidney, heart and fat, where clearance preserved the functionality of glomeruli, cardio-protective KATP channels and adipocytes, respectively. Thus, p16(Ink4a)-positive cells that accumulate during adulthood negatively influence lifespan and promote age-dependent changes in several organs, and their therapeutic removal may be an attractive approach to extend healthy lifespan.


Asunto(s)
Envejecimiento/patología , Envejecimiento/fisiología , Senescencia Celular/fisiología , Inhibidor p16 de la Quinasa Dependiente de Ciclina/metabolismo , Salud , Longevidad/fisiología , Adipocitos/citología , Adipocitos/patología , Adipocitos/fisiología , Animales , Apoptosis , Separación Celular , Transformación Celular Neoplásica/patología , Células Epiteliales/citología , Células Epiteliales/patología , Femenino , Riñón/citología , Riñón/patología , Riñón/fisiología , Riñón/fisiopatología , Lipodistrofia/patología , Masculino , Ratones , Miocardio/citología , Miocardio/metabolismo , Miocardio/patología , Especificidad de Órganos , Células Madre/citología , Células Madre/patología , Factores de Tiempo
16.
J Clin Invest ; 126(2): 543-59, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26731471

RESUMEN

The nuclear pore complex protein NUP88 is frequently elevated in aggressive human cancers and correlates with reduced patient survival; however, it is unclear whether and how NUP88 overexpression drives tumorigenesis. Here, we show that mice overexpressing NUP88 are cancer prone and form intestinal tumors. To determine whether overexpression of NUP88 drives tumorigenesis, we engineered transgenic mice with doxycycline-inducible expression of Nup88. Surprisingly, NUP88 overexpression did not alter global nuclear transport, but was a potent inducer of aneuploidy and chromosomal instability. We determined that NUP88 and the nuclear transport factors NUP98 and RAE1 comprise a regulatory network that inhibits premitotic activity of the anaphase-promoting complex/cyclosome (APC/C). When overexpressed, NUP88 sequesters NUP98-RAE1 away from APC/CCDH1, triggering proteolysis of polo-like kinase 1 (PLK1), a tumor suppressor and multitasking mitotic kinase. Premitotic destruction of PLK1 disrupts centrosome separation, causing mitotic spindle asymmetry, merotelic microtubule-kinetochore attachments, lagging chromosomes, and aneuploidy. These effects were replicated by PLK1 insufficiency, indicating that PLK1 is responsible for the mitotic defects associated with NUP88 overexpression. These findings demonstrate that the NUP88-NUP98-RAE1-APC/CCDH1 axis contributes to aneuploidy and suggest that it may be deregulated in the initiating stages of a broad spectrum of human cancers.


Asunto(s)
Ciclosoma-Complejo Promotor de la Anafase/metabolismo , Aneuploidia , Núcleo Celular/metabolismo , Cromosomas de los Mamíferos/metabolismo , Proteínas de Complejo Poro Nuclear/metabolismo , Transporte Activo de Núcleo Celular/genética , Ciclosoma-Complejo Promotor de la Anafase/genética , Animales , Núcleo Celular/genética , Núcleo Celular/patología , Centrosoma/metabolismo , Cromosomas de los Mamíferos/genética , Humanos , Ratones , Ratones Noqueados , Proteínas Asociadas a Matriz Nuclear/genética , Proteínas Asociadas a Matriz Nuclear/metabolismo , Proteínas de Complejo Poro Nuclear/genética , Proteínas de Transporte Nucleocitoplasmático/genética , Proteínas de Transporte Nucleocitoplasmático/metabolismo
17.
Nat Commun ; 5: 5744, 2014 Dec 11.
Artículo en Inglés | MEDLINE | ID: mdl-25501849

RESUMEN

Spartan (also known as DVC1 and C1orf124) is a PCNA-interacting protein implicated in translesion synthesis, a DNA damage tolerance process that allows the DNA replication machinery to replicate past nucleotide lesions. However, the physiological relevance of Spartan has not been established. Here we report that Spartan insufficiency in mice causes chromosomal instability, cellular senescence and early onset of age-related phenotypes. Whereas complete loss of Spartan causes early embryonic lethality, hypomorphic mice with low amounts of Spartan are viable. These mice are growth retarded and develop cataracts, lordokyphosis and cachexia at a young age. Cre-mediated depletion of Spartan from conditional knockout mouse embryonic fibroblasts results in impaired lesion bypass, incomplete DNA replication, formation of micronuclei and chromatin bridges and eventually cell death. These data demonstrate that Spartan plays a key role in maintaining structural and numerical chromosome integrity and suggest a link between Spartan insufficiency and progeria.


Asunto(s)
Caquexia/genética , Catarata/genética , Cromatina/química , Proteínas Cromosómicas no Histona/genética , Replicación del ADN , Proteínas de Unión al ADN/genética , Lordosis/genética , Progeria/genética , Animales , Caquexia/complicaciones , Caquexia/metabolismo , Caquexia/patología , Catarata/complicaciones , Catarata/metabolismo , Catarata/patología , Muerte Celular , Senescencia Celular/genética , Cromatina/patología , Proteínas Cromosómicas no Histona/deficiencia , Proteínas de Unión al ADN/deficiencia , Femenino , Fibroblastos/metabolismo , Fibroblastos/patología , Dosificación de Gen , Expresión Génica , Genes Letales , Inestabilidad Genómica , Integrasas/genética , Integrasas/metabolismo , Lordosis/complicaciones , Lordosis/metabolismo , Lordosis/patología , Masculino , Ratones , Ratones Noqueados , Micronúcleos con Defecto Cromosómico , Progeria/complicaciones , Progeria/metabolismo , Progeria/patología , Antígeno Nuclear de Célula en Proliferación/genética , Antígeno Nuclear de Célula en Proliferación/metabolismo , Transducción de Señal
18.
EMBO J ; 33(13): 1438-53, 2014 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-24825348

RESUMEN

Mice overexpressing the mitotic checkpoint kinase gene BubR1 live longer, whereas mice hypomorphic for BubR1 (BubR1(H/H)) live shorter and show signs of accelerated aging. As wild-type mice age, BubR1 levels decline in many tissues, a process that is proposed to underlie normal aging and age-related diseases. Understanding why BubR1 declines with age and how to slow this process is therefore of considerable interest. The sirtuins (SIRT1-7) are a family of NAD(+)-dependent deacetylases that can delay age-related diseases. Here, we show that the loss of BubR1 levels with age is due to a decline in NAD(+) and the ability of SIRT2 to maintain lysine-668 of BubR1 in a deacetylated state, which is counteracted by the acetyltransferase CBP. Overexpression of SIRT2 or treatment of mice with the NAD(+) precursor nicotinamide mononucleotide (NMN) increases BubR1 abundance in vivo. Overexpression of SIRT2 in BubR1(H/H) animals increases median lifespan, with a greater effect in male mice. Together, these data indicate that further exploration of the potential of SIRT2 and NAD(+) to delay diseases of aging in mammals is warranted.


Asunto(s)
Longevidad/fisiología , Proteínas Serina-Treonina Quinasas/metabolismo , Sirtuina 2/metabolismo , Animales , Proteínas de Ciclo Celular , Inducción Enzimática/fisiología , Células HeLa , Humanos , Masculino , Ratones , Ratones Noqueados , NAD/genética , NAD/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Sirtuina 2/genética
19.
Nat Cell Biol ; 15(1): 96-102, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23242215

RESUMEN

The BubR1 gene encodes for a mitotic regulator that ensures accurate segregation of chromosomes through its role in the mitotic checkpoint and the establishment of proper microtubule-kinetochore attachments. Germline mutations that reduce BubR1 abundance cause aneuploidy, shorten lifespan and induce premature ageing phenotypes and cancer in both humans and mice. A reduced BubR1 expression level is also a feature of chronological ageing, but whether this age-related decline has biological consequences is unknown. Using a transgenic approach in mice, we show that sustained high-level expression of BubR1 preserves genomic integrity and reduces tumorigenesis, even in the presence of genetic alterations that strongly promote aneuplodization and cancer, such as oncogenic Ras. We find that BubR1 overabundance exerts its protective effect by correcting mitotic checkpoint impairment and microtubule-kinetochore attachment defects. Furthermore, sustained high-level expression of BubR1 extends lifespan and delays age-related deterioration and aneuploidy in several tissues. Collectively, these data uncover a generalized function for BubR1 in counteracting defects that cause whole-chromosome instability and suggest that modulating BubR1 provides a unique opportunity to extend healthy lifespan.


Asunto(s)
Envejecimiento/metabolismo , Expresión Génica , Neoplasias Pulmonares/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Neoplasias Cutáneas/metabolismo , 9,10-Dimetil-1,2-benzantraceno , Envejecimiento/patología , Aneuploidia , Animales , Recuento de Células , Proteínas de Ciclo Celular , Células Cultivadas , Inestabilidad Cromosómica , Femenino , Esperanza de Vida , Neoplasias Pulmonares/inducido químicamente , Masculino , Ratones , Ratones de la Cepa 129 , Ratones Endogámicos C57BL , Ratones Transgénicos , Músculo Esquelético/metabolismo , Músculo Esquelético/patología , Fenotipo , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/fisiología , Neoplasias Cutáneas/inducido químicamente , Células Madre/patología
20.
J Cell Biol ; 199(6): 931-49, 2012 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-23209306

RESUMEN

The mitotic checkpoint protein Bub1 is essential for embryogenesis and survival of proliferating cells, and bidirectional deviations from its normal level of expression cause chromosome missegregation, aneuploidy, and cancer predisposition in mice. To provide insight into the physiological significance of this critical mitotic regulator at a modular level, we generated Bub1 mutant mice that lack kinase activity using a knockin gene-targeting approach that preserves normal protein abundance. In this paper, we uncover that Bub1 kinase activity integrates attachment error correction and mitotic checkpoint signaling by controlling the localization and activity of Aurora B kinase through phosphorylation of histone H2A at threonine 121. Strikingly, despite substantial chromosome segregation errors and aneuploidization, mice deficient for Bub1 kinase activity do not exhibit increased susceptibility to spontaneous or carcinogen-induced tumorigenesis. These findings provide a unique example of a modular mitotic activity orchestrating two distinct networks that safeguard against whole chromosome instability and reveal the differential importance of distinct aneuploidy-causing Bub1 defects in tumor suppression.


Asunto(s)
Fibroblastos/enzimología , Puntos de Control de la Fase M del Ciclo Celular/fisiología , Proteínas Serina-Treonina Quinasas/metabolismo , 9,10-Dimetil-1,2-benzantraceno/toxicidad , Aneuploidia , Animales , Aurora Quinasa B , Aurora Quinasas , Carcinógenos/toxicidad , Transformación Celular Neoplásica/inducido químicamente , Transformación Celular Neoplásica/genética , Células Cultivadas , Segregación Cromosómica/genética , Femenino , Fibroblastos/citología , Técnicas de Sustitución del Gen , Histonas/metabolismo , Puntos de Control de la Fase M del Ciclo Celular/genética , Masculino , Ratones , Fosforilación , Proteínas Serina-Treonina Quinasas/genética , Treonina/metabolismo
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