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1.
Funct Integr Genomics ; 19(5): 787-797, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31089837

RESUMO

Septins are GTP-binding proteins that polymerize to form filaments involved in several important biological processes. In human, 13 distinct septins genes are classified in four groups. Filaments formed by septins are complex and usually involve members of each group in specific positions. Expression data from GTEx database, a publicly available expression database with thousands of samples derived from multiple human tissues, was used to evaluate the expression of septins. The brain is noticeably a hotspot for septin expression where few genes contribute to a large portion of septin transcript pool. Co-expression data between septins suggests two predominant specific complexes in brain tissues and one filament in other tissues. SEPT3 and SEPT5 are two genes highly expressed in the brain and with a strong co-expression in all brain tissues. Additional analysis shows that the expression of these two genes is highly variable between individuals, but significantly dependent on the individual's age. Age-dependent decrease of expression from those two septins involved in synapses reinforces their possible link with cognitive decay and neurodegenerative diseases associated with aging. Analysis of enrichment of Gene Ontology terms from lists of genes consistently co-expressed with septins suggests participation in diverse biological processes, pointing out some novel roles for septins. Interestingly, we observed strong consistency of some of these terms with experimentally described roles of septins. Coordination of septins expression with genes involved in DNA repair and cell cycle control may provide insights for previously described links between septins and cancer.


Assuntos
Regulação da Expressão Gênica , Septinas/classificação , Septinas/metabolismo , Adulto , Fatores Etários , Idoso , Humanos , Pessoa de Meia-Idade , Septinas/genética , Distribuição Tecidual , Adulto Jovem
2.
J Dairy Res ; 86(2): 181-187, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31122298

RESUMO

This research paper addresses the hypothesis that Septin6 is a key regulatory factor influencing amino acid (AA)-mediated cell growth and casein synthesis in dairy cow mammary epithelial cells (DCMECs). DCMECs were treated with absence of AA (AA-), restricted concentrations of AA (AAr) or normal concentrations of AA (AA+) for 24 h. Cell growth, expression of CSN2 and Septin6 were increased in response to AA supply. Overexpressing or inhibiting Septin6 demonstrated that cell growth, expression of CSN2, mTOR, p-mTOR, S6K1 and p-S6K1 were up-regulated by Septin6. Furthermore, overexpressing or inhibiting mTOR demonstrated that the increase in cell growth and expression of CSN2 in response to Septin6 overexpression were inhibited by mTOR inhibition, and vice versa. Our hypothesis was supported; we were able to show that Septin6 is an important positive factor for cell growth and casein synthesis, it up-regulates AA-mediated cell growth and casein synthesis through activating mTORC1 pathway in DCMECs.


Assuntos
Aminoácidos/farmacologia , Caseínas/metabolismo , Células Epiteliais/metabolismo , Glândulas Mamárias Animais/citologia , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Septinas/metabolismo , Animais , Caseínas/genética , Bovinos , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Septinas/genética
3.
World J Gastroenterol ; 25(17): 2099-2109, 2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31114136

RESUMO

BACKGROUND: The methylated septin 9 (mSEPT9) assay was the first blood-based test approved by the United States Food and Drug Administration as a colorectal screening test. However, the diagnostic and prognostic role of preoperative mSEPT9 for colorectal cancer (CRC) in Chinese patients is still unknown. AIM: To improve the understanding of diagnostic and prognostic factors, serum mSEPT9 was detected in Chinese CRC patients. METHODS: A retrospective analysis of 354 cases, of which 300 had CRC and 54 were normal, was performed in China. Patients' characteristics, treatments, and laboratory data, including age, the date of surgery, Union for International Cancer Control (UICC) stages, distant metastasis (M), and so on, were collected. Methylation levels of SEPT9 were quantified by quantitative, methylation-specific polymerase chain reaction before surgery. In addition, the effects of mSEPT9 on the occurrence and prognosis of 330 CRC cases from The Cancer Genome Atlas (TCGA) database were evaluated using bioinformatics analyses. Potential prognostic factors for overall survival (OS) and progression-free survival (PFS) were evaluated by Kaplan-Meier univariate analysis. RESULTS: In Chinese CRC patients, positive mSEPT9 was strongly associated with advanced UICC stages, deeper invasion by the primary tumor, and more distant metastasis. Methylation levels of SEPT9 were stage-dependent and showed a stepwise increase in UICC stages (I-IV), primary tumor categories (T1-T4), regional node categories (N0-N2), and distant metastasis categories (M0-M1). The patients with positive mSEPT9 showed a tendency toward lower PFS. After analyzing TCGA clinical data, the high mSEPT9 group was found to be obviously correlated only with more distant metastasis. The patients with high mSEPT9 levels showed a tendency toward lower OS. Besides, nine meaningful mSEPT9 sites were found to provide guidance for the follow-up studies. CONCLUSION: MSEPT9 analysis may add valuable information to current tumor staging. Serum mSEPT9 in Chinese CRC patients appears to offer promising novel prognostic markers and might be considered for monitoring CRC recurrence.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias Colorretais/diagnóstico , Septinas/metabolismo , Adenoma/sangue , Adenoma/diagnóstico , Adenoma/cirurgia , Idoso , China , Neoplasias Colorretais/sangue , Neoplasias Colorretais/cirurgia , Biologia Computacional , Metilação de DNA , Detecção Precoce de Câncer , Feminino , Perfilação da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Período Pré-Operatório , Prognóstico , Estudos Retrospectivos
4.
G3 (Bethesda) ; 9(6): 1869-1880, 2019 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-30975701

RESUMO

Septins regulate the organization of the actin cytoskeleton, vesicle transport and fusion, chromosome alignment and segregation, and cytokinesis in mammalian cells. SEPT9 is part of the core septin hetero-octamer in human cells which is composed of SEPT2, SEPT6, SEPT7, and SEPT9. SEPT9 has been linked to a variety of intracellular functions as well as to diseases and diverse types of cancer. A targeted high-throughput approach to systematically identify the interaction partners of SEPT9 has not yet been performed. We applied a quantitative proteomics approach to establish an interactome of SEPT9 in human fibroblast cells. Among the newly identified interaction partners were members of the myosin family and LIM domain containing proteins. Fluorescence microscopy of SEPT9 and its interaction partners provides additional evidence that SEPT9 might participate in vesicle transport from and to the plasma membrane as well as in the attachment of actin stress fibers to cellular adhesions.


Assuntos
Espectrometria de Massas , Mapeamento de Interação de Proteínas , Mapas de Interação de Proteínas , Septinas/metabolismo , Linhagem Celular , Fibroblastos , Imunofluorescência , Humanos , Espectrometria de Massas/métodos , Espectrometria de Massas/normas , Ligação Proteica , Mapeamento de Interação de Proteínas/métodos , Isoformas de Proteínas , Transporte Proteico
5.
Int J Biol Macromol ; 133: 428-435, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31002902

RESUMO

Septins are members of a group of GTP-binding proteins highly conserved in eukaryotes, being linked to diverse cell processes, such as cytokinesis and membrane association. On the other hand, the malfunction of septins is linked to several pathological processes including neurodegeneration and oncogenesis. Septins interact with each other forming heterocomplexes that polymerize in filaments. Two types of interface between septins alternate along the filament: the G-interface (involving the GTP binding sites), and the NC-interface. This work focuses on the physiological G-interface of SEPT2, used in the SEPT6G-SEPT2G heterodimer assembly, to verify the impact of this interaction on the thermostability and amyloid formation. We found that the SEPT6G-SEPT2G moves to an irreversible state with the ability to bind thioflavin-T at high temperatures, suggesting its amyloid-like nature. Noteworthy, this takes place at a higher temperature than the one observed to the single septins, showing greater thermal/structural stability. Taken together, our results show that in the absence of the partners, the septin becomes unstable and susceptible to amyloid aggregation/formation even in physiological temperatures, and the G-interface appears to have a critical role in this process.


Assuntos
Amiloide/química , Agregados Proteicos , Septinas/química , Septinas/metabolismo , Estabilidade Enzimática , Domínios Proteicos , Multimerização Proteica , Estrutura Quaternária de Proteína , Especificidade por Substrato , Temperatura Ambiente
6.
Cell Mol Neurobiol ; 39(5): 715-720, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30915622

RESUMO

The serotoninergic system plays a key role in environmental sensitivity, potentially through down-stream effects on the GABAergic and glutamatergic systems. We previously demonstrated that juvenile serotonin transporter knockout (SERT-/-) rats, showing increased environmental sensitivity, exhibit a decreased GABA-mediated inhibitory tone in the cortex. Since the GABAergic and glutamatergic systems are tightly interconnected, we here analyzed glutamatergic markers in the prefrontal cortex of SERT-/- rats, from the early stages of life until adulthood. We found that SERT inactivation in pre-weaning, juvenile, and adult rats was associated with reduced expression of proteins essential for the glutamatergic synapses such as GluN1, PSD95, CDC42, and SEPT7. These lifelong molecular changes may destabilize glutamatergic signaling and possibly contribute to stress sensitivity and vulnerability to stress-related disorders associated with SERT alteration.


Assuntos
Glutamatos/metabolismo , Córtex Pré-Frontal/crescimento & desenvolvimento , Córtex Pré-Frontal/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Animais , Biomarcadores/metabolismo , Proteína 4 Homóloga a Disks-Large/genética , Proteína 4 Homóloga a Disks-Large/metabolismo , Regulação da Expressão Gênica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ratos Wistar , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/metabolismo , Septinas/genética , Septinas/metabolismo , Proteína cdc42 de Ligação ao GTP/genética , Proteína cdc42 de Ligação ao GTP/metabolismo
7.
Mol Med Rep ; 19(5): 4401-4406, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30896847

RESUMO

The objective of the present study was to investigate the effects of for chlorfenuron (FCF) interference with the septin protein on early stage embryos in mice. The 1­cell embryos were collected and divided into an FCF interference group and a control group. The FCF interference group was cultured in FCF media and the control group was cultured in dimethyl sulphoxide media at 37˚C with 5% CO2 until the desired phase was achieved. Septin2 protein expression was detected using immunofluorescence and western blot analysis. Blastocyst α­tubulin was stained by immunofluorescence to observe the alterations in spindles and microtubules. The rate of early embryo development into blastocysts was significantly reduced following FCF treatment (P<0.05). In the control group, septin2 was observed with a confocal microscope; septin2 was expressed in embryos at all stages and mainly in the blastomeres from the 2­cell stage onwards, with the expression concentrated in the nuclei of the blastomeres as identified by strong fluorescence. In the FCF interference group, septin2 was weakly expressed in the nuclei of blastomeres at the 2­ and 4­cell stages, and in the granulated blastomeres at the 4­ and 8­cell stages. Expression was barely observed in and following the morula. Granulation was observed starting from the 4­ and 8­cell stages. Compared with the control group, the FCF interference group exhibited irregular microtubules, abnormal spindle morphology and disordered chromosome arrangement in the blastocysts. The septin2 protein was expressed throughout the early stage embryo from the 2­cell stage to the blastocyst and localized in the nuclei of blastomeres. When the septin protein experienced interference by the FCF inhibitor, septin2 protein expression was reduced, which simultaneously resulted in abnormal embryonic development, uneven cytoplasmic division, various sizes and a reduced number of blastomeres, granulation in the blastomeres, disordered blastocyst microtubule distribution, spindle shape alterations and an abnormality of chromosome arrangement.


Assuntos
Embrião de Mamíferos/efeitos dos fármacos , Compostos de Fenilureia/farmacologia , Septinas/metabolismo , Animais , Blastocisto/citologia , Blastocisto/metabolismo , Blastômeros/citologia , Blastômeros/metabolismo , Núcleo Celular/metabolismo , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Desenvolvimento Embrionário/efeitos dos fármacos , Feminino , Camundongos , Microscopia de Fluorescência , Septinas/genética , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo
8.
Int J Mol Sci ; 20(5)2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30866452

RESUMO

Male infertility is observed in approximately 50% of all couples with infertility. Intracytoplasmic sperm injection (ICSI), a conventional artificial reproductive technique for treating male infertility, may fail because of a severe low sperm count, immotile sperm, immature sperm, and sperm with structural defects and DNA damage. Our previous studies have revealed that mutations in the septin (SEPT)-coding gene SEPT12 cause teratozoospermia and severe oligozoospermia. These spermatozoa exhibit morphological defects in the head and tail, premature chromosomal condensation, and nuclear damage. Sperm from Sept12 knockout mice also cause the developmental arrest of preimplantation embryos generated through in vitro fertilization and ICSI. Furthermore, we found that SEPT12 interacts with SPAG4, a spermatid nuclear membrane protein that is also named SUN4. Loss of the Spag4 allele in mice also disrupts the integration nuclear envelope and reveals sperm head defects. However, whether SEPT12 affects SPAG4 during mammalian spermiogenesis remains unclear. We thus conducted this study to explore this question. First, we found that SPAG4 and SEPT12 exhibited similar localizations in the postacrosomal region of elongating spermatids and at the neck of mature sperm through isolated murine male germ cells. Second, SEPT12 expression altered the nuclear membrane localization of SPAG4, as observed through confocal microscopy, in a human testicular cancer cell line. Third, SEPT12 expression also altered the localizations of nuclear membrane proteins: LAMINA/C in the cells. This effect was specifically due to the expression of SEPT12 and not that of SEPT1, SEPT6, SEPT7, or SEPT11. Based on these results, we suggest that SEPT12 is among the moderators of SPAG4/LAMIN complexes and is involved in the morphological formation of sperm during mammalian spermiogenesis.


Assuntos
Proteínas de Transporte/metabolismo , Núcleo Celular/metabolismo , Proteínas Nucleares/metabolismo , Septinas/metabolismo , Espermatogênese , Animais , Proteínas de Transporte/genética , Células Cultivadas , Técnicas de Inativação de Genes , Humanos , Lamina Tipo A/metabolismo , Masculino , Camundongos , Microscopia Confocal , Proteínas Nucleares/genética , Especificidade de Órgãos , Septinas/genética , Teratozoospermia/genética , Teratozoospermia/metabolismo , Testículo/metabolismo
9.
Neuron ; 101(6): 1089-1098.e4, 2019 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-30713029

RESUMO

Zika virus (ZIKV) targets neural progenitor cells in the brain, attenuates cell proliferation, and leads to cell death. Here, we describe a role for the ZIKV protease NS2B-NS3 heterodimer in mediating neurotoxicity through cleavage of a host protein required for neurogenesis. Similar to ZIKV infection, NS2B-NS3 expression led to cytokinesis defects and cell death in a protease activity-dependent fashion. Among binding partners, NS2B-NS3 cleaved Septin-2, a cytoskeletal factor involved in cytokinesis. Cleavage of Septin-2 occurred at residue 306 and forced expression of a non-cleavable Septin-2 restored cytokinesis, suggesting a direct mechanism of ZIKV-induced neural toxicity. VIDEO ABSTRACT.


Assuntos
Apoptose , Citocinese , Mitose , Células-Tronco Neurais/metabolismo , Septinas/metabolismo , Proteínas não Estruturais Virais/metabolismo , Zika virus/metabolismo , Citoesqueleto/metabolismo , Células HEK293 , Células HeLa , Humanos , Neurogênese , RNA Helicases/metabolismo , Serina Endopeptidases/metabolismo
10.
Curr Protein Pept Sci ; 20(6): 547-562, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30659536

RESUMO

Substrate pleiotropicity, a very acidic phosphorylation consensus sequence, and an apparent uncontrolled activity, are the main features of CK2, a Ser/Thr protein kinase that is required for a plethora of cell functions. Not surprisingly, CK2 appears to affect cytoskeletal structures and correlated functions such as cell shape, mechanical integrity, cell movement and division. This review outlines our current knowledge of how CK2 regulates cytoskeletal structures, and discusses involved pathways and molecular mechanisms.


Assuntos
Caseína Quinase II/metabolismo , Citoesqueleto/metabolismo , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Animais , Caseína Quinase II/química , Divisão Celular , Movimento Celular , Forma Celular , Humanos , Fosforilação , Conformação Proteica , Processamento de Proteína Pós-Traducional , Septinas/metabolismo , Transdução de Sinais , Tubulina (Proteína)/metabolismo
11.
Cancer Sci ; 110(2): 540-549, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30444001

RESUMO

Hepatocellular carcinoma (HCC) is a common and aggressive malignant tumor with a poorly defined molecular mechanism. Cyclin-dependent kinase 2 (CDK2) and Septin2 (SEPT2) are 2 known oncogenic molecules but the mechanism of functional interactions remains unclear. Here, we interestingly found that CDK2 and SEPT2 show very similar dynamic expression during the cell cycle. Both CDK2 and SEPT2 show the highest protein levels in the G2/M phase, resulting in CDK2 interacting with SEPT2 and stabilizing SEPT2 in HCC. In a panel of 8 pairs of fresh HCC tissues and corresponding adjacent tissues, both western blot and immunohistochemistry (IHC) assays demonstrate that CDK2 expression is highly correlated with SEPT2. HCC with high expression of both CDK2 and SEPT2 are more likely to relapse. This observation is further demonstrated by a large panel of 100 HCC patients. In this large panel, high expression of both CDK2 and SEPT2 significantly correlates with tumor differentiation and microvascular invasion, which is an independent prognostic factor in HCC patients. In summary, our results reveal a cooperative function between CDK2 and SEPT2. HCC with high expression of CDK2 and SEPT2 might be more aggressive and respond poorly to current therapy.


Assuntos
Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Septinas/metabolismo , Animais , Linhagem Celular Tumoral , Quinase 2 Dependente de Ciclina/metabolismo , Feminino , Humanos , Imuno-Histoquímica/métodos , Masculino , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/metabolismo , Recidiva Local de Neoplasia/patologia
12.
Genetics ; 211(1): 151-167, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30446520

RESUMO

The pathogenic life cycle of the rice blast fungus Magnaporthe oryzae involves a series of morphogenetic changes, essential for its ability to cause disease. The smo mutation was identified > 25 years ago, and affects the shape and development of diverse cell types in M. oryzae, including conidia, appressoria, and asci. All attempts to clone the SMO1 gene by map-based cloning or complementation have failed over many years. Here, we report the identification of SMO1 by a combination of bulk segregant analysis and comparative genome analysis. SMO1 encodes a GTPase-activating protein, which regulates Ras signaling during infection-related development. Targeted deletion of SMO1 results in abnormal, nonadherent conidia, impaired in their production of spore tip mucilage. Smo1 mutants also develop smaller appressoria, with a severely reduced capacity to infect rice plants. SMO1 is necessary for the organization of microtubules and for septin-dependent remodeling of the F-actin cytoskeleton at the appressorium pore. Smo1 physically interacts with components of the Ras2 signaling complex, and a range of other signaling and cytoskeletal components, including the four core septins. SMO1 is therefore necessary for the regulation of RAS activation required for conidial morphogenesis and septin-mediated plant infection.


Assuntos
Proteínas Fúngicas/genética , Magnaporthe/genética , Receptor Smoothened/genética , Esporos Fúngicos/crescimento & desenvolvimento , Citoesqueleto de Actina/metabolismo , Proteínas Fúngicas/metabolismo , Magnaporthe/crescimento & desenvolvimento , Magnaporthe/patogenicidade , Microtúbulos/metabolismo , Morfogênese , Oryza/microbiologia , Septinas/metabolismo , Transdução de Sinais , Receptor Smoothened/metabolismo , Esporos Fúngicos/genética , Virulência/genética
13.
Lab Invest ; 99(1): 17-36, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30315255

RESUMO

Hepatic stellate cells (HSCs) are key effectors during the development of liver fibrosis. Septin 6 (SEPT6) is a highly evolutionarily conserved GTP-binding protein that regulates various cell biological behaviors. The expression and function of SEPT6 in HSCs remain unknown. Here we demonstrate that SEPT6 expression is significantly elevated following the activation of primary rat HSCs, the human hepatic stellate cell line LX-2 and the rat hepatic stellate cell line HSC-T6, as well as in both human and rat fibrotic liver tissue. In vitro, the overexpression of SEPT6 promoted HSCs activation, proliferation, cell cycle progression and migration and inhibited HSCs apoptosis. In contrast, knockdown of SEPT6 exerted the opposite effects on HSCs. Mechanistically, SEPT6 exerted its pro-fibrogenic effect by promoting the expression of TGF-ß1 and the phosphorylation of Smad2, Smad3, extracellular-signal-regulated kinase, c-Jun NH2-terminal kinase, stress-activated protein kinase-2, and protein kinase B. However, in HSC-T6 cells, blockade of the TGF-ß1/Smad signaling pathway by SB431542 significantly decreased the expression of α-smooth muscle actin, cyclin D1, BCL2, and matrix metalloproteinase-2 and -9, which had been enhanced by SEPT6 overexpression. In vivo, adenovirus-mediated SEPT6 inhibition attenuated thioacetamide (TAA)-induced liver fibrosis in rats by decreasing the deposition of the extracellular matrix (ECM). SEPT6 inhibition decreased the proliferation capacity of HSCs and induced apoptosis of HSCs. Collectively, our results reveal that SEPT6 regulates various biological behaviors in HSCs through TGF-ß1/Smad, mitogen-activated protein kinases and phosphatidylinositol-3-kinase/protein kinase B signaling pathways, thus promoting liver fibrosis.


Assuntos
Células Estreladas do Fígado/metabolismo , Cirrose Hepática/etiologia , Septinas/metabolismo , Animais , Apoptose , Ciclo Celular , Linhagem Celular , Movimento Celular , Proliferação de Células , Humanos , Fígado/patologia , Cirrose Hepática/metabolismo , Cirrose Hepática/patologia , Ratos , Transdução de Sinais , Proteínas Smad/metabolismo , Fator de Crescimento Transformador beta/metabolismo
14.
Cell Host Microbe ; 24(6): 866-874.e4, 2018 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-30543779

RESUMO

The cytoskeleton occupies a central role in cellular immunity by promoting bacterial sensing and antibacterial functions. Septins are cytoskeletal proteins implicated in various cellular processes, including cell division. Septins also assemble into cage-like structures that entrap cytosolic Shigella, yet how septins recognize bacteria is poorly understood. Here, we discover that septins are recruited to regions of micron-scale membrane curvature upon invasion and division by a variety of bacterial species. Cardiolipin, a curvature-specific phospholipid, promotes septin recruitment to highly curved membranes of Shigella, and bacterial mutants lacking cardiolipin exhibit less septin cage entrapment. Chemically inhibiting cell separation to prolong membrane curvature or reducing Shigella cell growth respectively increases and decreases septin cage formation. Once formed, septin cages inhibit Shigella cell division upon recruitment of autophagic and lysosomal machinery. Thus, recognition of dividing bacterial cells by the septin cytoskeleton is a powerful mechanism to restrict the proliferation of intracellular bacterial pathogens.


Assuntos
Lisossomos/metabolismo , Pseudomonas aeruginosa/fisiologia , Septinas/metabolismo , Shigella flexneri/fisiologia , Staphylococcus aureus/fisiologia , Autofagia , Cardiolipinas/genética , Cardiolipinas/metabolismo , Divisão Celular , Proliferação de Células , Citoesqueleto/metabolismo , Células HeLa , Humanos , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidade , Septinas/genética , Shigella flexneri/genética , Shigella flexneri/patogenicidade , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidade
15.
PLoS One ; 13(12): e0200863, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30566437

RESUMO

The conserved Rho-family GTPase Cdc42 is a master regulator of polarity establishment in many cell types. Cdc42 becomes activated and concentrated in a region of the cell cortex, and recruits a variety of effector proteins to that site. In turn, many effectors participate in regulation of cytoskeletal elements in order to remodel the cytoskeleton in a polarized manner. The budding yeast Saccharomyces cerevisiae has served as a tractable model system for studies of cell polarity. In yeast cells, Cdc42 polarization involves a positive feedback loop in which effectors called p21-activated kinases (PAKs) act to recruit a Cdc42-directed guanine nucleotide exchange factor (GEF), generating more GTP-Cdc42 in areas that already have GTP-Cdc42. The GTPase-interacting components (GICs) Gic1 and Gic2 are also Cdc42 effectors, and have been implicated in regulation of the actin and septin cytoskeleton. However, we report that cells lacking GICs are primarily defective in polarizing Cdc42 itself, suggesting that they act upstream as well as downstream of Cdc42 in yeast. Our findings suggest that feedback pathways involving GTPase effectors may be more prevalent than had been appreciated.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Temperatura Alta , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Proteína cdc42 de Ligação ao GTP/metabolismo , Citoesqueleto de Actina/genética , Citoesqueleto de Actina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Septinas/genética , Septinas/metabolismo , Proteína cdc42 de Ligação ao GTP/genética
16.
Nat Commun ; 9(1): 4582, 2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-30389919

RESUMO

Stem cells (SCs) play a pivotal role in fueling homeostasis and regeneration. While much focus has been given to self-renewal and differentiation pathways regulating SC fate, little is known regarding the specific mechanisms utilized for their elimination. Here, we report that the pro-apoptotic protein ARTS (a Septin4 isoform) is highly expressed in cells comprising the intestinal SC niche and that its deletion protects Lgr5+ and Paneth cells from undergoing apoptotic cell death. As a result, the Sept4/ARTS-/- crypt displays augmented proliferation and, in culture, generates massive cystic-like organoids due to enhanced Wnt/ß-catenin signaling. Importantly, Sept4/ARTS-/- mice exhibit resistance against intestinal damage in a manner dependent upon Lgr5+ SCs. Finally, we show that ARTS interacts with XIAP in intestinal crypt cells and that deletion of XIAP can abrogate Sept4/ARTS-/--dependent phenotypes. Our results indicate that intestinal SCs utilize specific apoptotic proteins for their elimination, representing a unique target for regenerative medicine.


Assuntos
Apoptose , Intestinos/citologia , Regeneração , Septinas/metabolismo , Nicho de Células-Tronco , Animais , Proliferação de Células , Citoproteção , Deleção de Genes , Camundongos Endogâmicos C57BL , Via de Sinalização Wnt , Ferimentos e Lesões/patologia , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo
17.
Artigo em Inglês | MEDLINE | ID: mdl-30455225

RESUMO

Acute megakaryoblastic leukemia (AMKL) constitutes ∼5%-15% of cases of non-Down syndrome AML in children, and in the majority of cases, chimeric oncogenes resulting from recurrent gene rearrangements are identified. Based on these rearrangements, several molecular subsets have been characterized providing important prognostic information. One such subset includes a group of patients with translocations involving the KMT2A gene, which has been associated with various fusion partners in patients with AMKL. Here we report the molecular findings of a 2-yr-old girl with AMKL and t(11;17)(q23;25) found to have a KMT2A-SEPT9 fusion identified through targeted RNA sequencing. A KMT2A-SEPT9 fusion in this subset of patients has not previously been reported.


Assuntos
Histona-Lisina N-Metiltransferase/genética , Leucemia Megacarioblástica Aguda/genética , Proteína de Leucina Linfoide-Mieloide/genética , Septinas/genética , Transplante de Medula Óssea , Pré-Escolar , Feminino , Rearranjo Gênico , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Leucemia Megacarioblástica Aguda/metabolismo , Proteína de Leucina Linfoide-Mieloide/metabolismo , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Prognóstico , Septinas/metabolismo , Translocação Genética/genética
18.
Anal Chim Acta ; 1038: 157-165, 2018 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-30278898

RESUMO

Determining methylation state of a particular DNA sequence is an essential task in many epigenetic investigations. Here a facile method based on silver nanocluster (AgNCs) fluorescence enhancement is presented. Target sequences were selected from Sept9 promoter region that its hypermethylation is demonstrated as a reliable biomarker of colorectal cancer. Probe DNA was complementary to a 25 nucleotide of the target region and possessed twelve additional cytosines in the middle to grant the formation of AgNCs. After probe strands were hybridized with methylated and non-methylated targets separately, AgNCs were synthesized, and their fluorescence intensities were recorded. Fluorescence intensity enhanced when the target strands were methylated and quenched when they were non-methylated. The Linear range of fluorescence enhancement was from 1.0 × 10-7 M to 5.0 × 10-7 M with the detection limit of 7.6 × 10-8 M. Sensor specificity was checked with non-complementary strands with the maximum similarity of 40%. Further experiments explored various characteristics of methylated and non-methylated DNAs carrying AgNC and indicated that structure of methylated and non-methylated DNAs was affected differently by silver ions that could then influence AgNC fluorescence. This effect was strongly sequence-dependent, and either fluorescence enhancement or quenching was observed with two different sequences.


Assuntos
Técnicas Biossensoriais , Sondas de DNA/química , Fluorescência , Nanopartículas Metálicas/química , Regiões Promotoras Genéticas/genética , Septinas/genética , Prata/química , Metilação de DNA , Septinas/metabolismo , Espectrometria de Fluorescência
19.
Biochem Biophys Res Commun ; 506(3): 522-528, 2018 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-30361092

RESUMO

Podocyte depletion is a central pathological mechanism of diabetic nephropathy (DN). Hyperglycemia induced podocyte apoptosis, resulting in podocyte depletion. However, the crucial mechanism of hyperglycemia-induced podocyte apoptosis remains poorly understood. In this study, we evaluated the expression of septin 7, a GTP-binding protein, in glomerular podocytes of patients and mice with DN, and investigated the pro-apoptotic effect of septin 7 on high glucose (HG) induced podocyte apoptosis in vitro. We found septin 7 expression was markedly increased not only in glomerular podocytes of patients and db/db mice with DN but also in cultured podocytes with HG stimulation. Knocking down septin 7 with siRNA could attenuate HG induced podocytes apoptosis and excessive intracellular Ca2+ concentration. This study revealed septin7 may potentially play a proapoptotic role in podocyte under diabetic conditions and may provide a potential target for preventing podocyte apoptosis in DN.


Assuntos
Apoptose , Proteínas de Ciclo Celular/metabolismo , Podócitos/metabolismo , Podócitos/patologia , Septinas/metabolismo , Animais , Cálcio/metabolismo , Células Cultivadas , Nefropatias Diabéticas/patologia , Técnicas de Silenciamento de Genes , Glucose , Humanos , Espaço Intracelular/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/metabolismo
20.
Cell Rep ; 25(4): 862-870, 2018 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-30355493

RESUMO

Dss1 (also known as Sem1) is a conserved, intrinsically disordered protein with a remarkably broad functional diversity. It is a proteasome subunit but also associates with the BRCA2, RPA, Csn12-Thp1, and TREX-2 complexes. Accordingly, Dss1 functions in protein degradation, DNA repair, transcription, and mRNA export. Here in Schizosaccharomyces pombe, we expand its interactome further to include eIF3, the COP9 signalosome, and the mitotic septins. Within its intrinsically disordered ensemble, Dss1 forms a transiently populated C-terminal helix that dynamically interacts with and shields a central binding region. The helix interfered with the interaction to ATP-citrate lyase but was required for septin binding, and in strains lacking Dss1, ATP-citrate lyase solubility was reduced and septin rings were more persistent. Thus, even weak, transient interactions within Dss1 may dynamically rewire its interactome.


Assuntos
Proteínas Intrinsicamente Desordenadas/metabolismo , Mapeamento de Interação de Proteínas , Proteínas de Schizosaccharomyces pombe/metabolismo , Schizosaccharomyces/metabolismo , ATP Citrato (pro-S)-Liase/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Proteínas Intrinsicamente Desordenadas/química , Mitose , Ligação Proteica , Estrutura Secundária de Proteína , Proteínas de Schizosaccharomyces pombe/química , Septinas/metabolismo
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