RESUMO
SUMO modification regulates diverse cellular processes by targeting hundreds of proteins. However, the limited number of sumoylation enzymes raises the question of how such a large number of substrates are efficiently modified. Specifically, how genome maintenance factors are dynamically sumoylated at DNA replication and repair sites to modulate their functions is poorly understood. Here, we demonstrate a role for the conserved yeast Esc2 protein in this process by acting as a SUMO E2 cofactor. Esc2 is required for genome stability and binds to Holliday junctions and replication fork structures. Our targeted screen found that Esc2 promotes the sumoylation of a Holliday junction dissolution complex and specific replisome proteins. Esc2 does not elicit these effects via stable interactions with substrates or their common SUMO E3. Rather, we show that a SUMO-like domain of Esc2 stimulates sumoylation by exploiting a noncovalent SUMO binding site on the E2 enzyme. This role of Esc2 in sumoylation is required for Holliday junction clearance and genome stability. Our findings thus suggest that Esc2 acts as a SUMO E2 cofactor at distinct DNA structures to promote the sumoylation of specific substrates and genome maintenance.
Assuntos
Proteínas de Ciclo Celular/metabolismo , Genoma Fúngico/genética , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Sumoilação/genética , Coenzimas/metabolismo , Instabilidade Genômica/genética , Ligação Proteica , Recombinação Genética , Enzimas de Conjugação de Ubiquitina/metabolismoRESUMO
BRCT domains support myriad protein-protein interactions involved in genome maintenance. Although di-BRCT recognition of phospho-proteins is well known to support the genotoxic response, whether multi-BRCT domains can acquire distinct structures and functions is unclear. Here we present the tetra-BRCT structures from the conserved yeast protein Rtt107 in free and ligand-bound forms. The four BRCT repeats fold into a tetrahedral structure that recognizes unmodified ligands using a bi-partite mechanism, suggesting repeat origami enabling function acquisition. Functional studies show that Rtt107 binding of partner proteins of diverse activities promotes genome replication and stability in both distinct and concerted manners. A unified theme is that tetra- and di-BRCT domains of Rtt107 collaborate to recruit partner proteins to chromatin. Our work thus illustrates how a master regulator uses two types of BRCT domains to recognize distinct genome factors and direct them to chromatin for constitutive genome protection.
Assuntos
Instabilidade Genômica/genética , Proteínas Nucleares/ultraestrutura , Domínios e Motivos de Interação entre Proteínas/genética , Proteínas de Saccharomyces cerevisiae/ultraestrutura , Saccharomyces cerevisiae/genética , Cromatina/genética , Dano ao DNA/genética , Ligantes , Proteínas Nucleares/química , Proteínas Nucleares/genética , Fosforilação , Ligação Proteica , Domínios Proteicos/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genéticaRESUMO
Structural maintenance of chromosomes (SMC) complexes are critical chromatin modulators. In eukaryotes, the cohesin and condensin SMC complexes organize chromatin, while the Smc5/6 complex directly regulates DNA replication and repair. The molecular basis for the distinct functions of Smc5/6 is poorly understood. Here, we report an integrative structural study of the budding yeast Smc5/6 holo-complex using electron microscopy, cross-linking mass spectrometry, and computational modeling. We show that the Smc5/6 complex possesses several unique features, while sharing some architectural characteristics with other SMC complexes. In contrast to arm-folded structures of cohesin and condensin, Smc5 and Smc6 arm regions do not fold back on themselves. Instead, these long filamentous regions interact with subunits uniquely acquired by the Smc5/6 complex, namely the Nse2 SUMO ligase and the Nse5/Nse6 subcomplex, with the latter also serving as a linchpin connecting distal parts of the complex. Our 3.0-Å resolution cryoelectron microscopy structure of the Nse5/Nse6 core further reveals a clasped-hand topology and a dimeric interface important for cell growth. Finally, we provide evidence that Nse5/Nse6 uses its SUMO-binding motifs to contribute to Nse2-mediated sumoylation. Collectively, our integrative study identifies distinct structural features of the Smc5/6 complex and functional cooperation among its coevolved unique subunits.
Assuntos
Proteínas de Ciclo Celular/química , Complexos Multiproteicos/química , Domínios Proteicos , Proteínas de Saccharomyces cerevisiae/química , Saccharomyces cerevisiae/metabolismo , Sítios de Ligação , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/química , Proteínas Cromossômicas não Histona/metabolismo , Microscopia Crioeletrônica/métodos , Espectrometria de Massas/métodos , Modelos Moleculares , Complexos Multiproteicos/metabolismo , Complexos Multiproteicos/ultraestrutura , Ligação Proteica , Proteínas de Saccharomyces cerevisiae/metabolismo , SumoilaçãoRESUMO
A new sandwich-type electrochemical biosensing platform was developed by gold @polyphthalenediamine nanohybrids (AuNP@PoPD) as the sensing platform and phosphorus doped reduced graphene oxide-hemin-palladium nanoparticles (PrGO-Hemin-PdNP) as the signal amplifier for phosphatidylinositol proteoglycan 3 (GPC3). AuNP@PoPD, co-electrodeposited into the screen printed electrode with high conductivity and stability, is dedicated to assembling the primary GPC3 aptamer (GPC3Apt). The second GPC3Apt immobilized on the high conductivity and large surface area of PrGO-Hemin-PdNP was utilized as an electrochemical signal reporter by hemin oxidation (PrGO-Hemin-PdNP-GPC3Apt). In the range 0.001-10.0 ng/mL, the hemin oxidation current signal of the electrochemical aptasensor increased log-linearly with the concentration of GPC3, the lowest detection limit was 0.13 pg/mL, and the sensitivity was 2.073 µA/µM/cm2. The aptasensor exhibited good sensing performance in a human serum sample with the relative error of 4.31-8.07%. The sandwich sensor showed good selectivity and stability for detection GPC3 in human serum samples, providing a new efficient and sensitive method for detecting HCC markers.
Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Técnicas Eletroquímicas , Glipicanas , Ouro , Grafite , Hemina , Limite de Detecção , Nanopartículas Metálicas , Paládio , Glipicanas/sangue , Humanos , Técnicas Eletroquímicas/métodos , Técnicas Eletroquímicas/instrumentação , Aptâmeros de Nucleotídeos/química , Hemina/química , Grafite/química , Paládio/química , Ouro/química , Técnicas Biossensoriais/métodos , Nanopartículas Metálicas/química , EletrodosRESUMO
Gametogenesis is an essential step for malaria parasite transmission and is activated in mosquito by signals including temperature drop, pH change, and mosquito-derived xanthurenic acid (XA). Recently, a membrane protein gametogenesis essential protein 1 (GEP1) was found to be responsible for sensing these signals and interacting with a giant guanylate cyclase α (GCα) to activate the cGMP-PKG-Ca2+ signaling pathway for malaria parasite gametogenesis. However, the molecular mechanisms for this process remain unclear. In this study, we used AlphaFold2 to predict the structure of GEP1 and found that it consists of a conserved N-terminal helical domain and a transmembrane domain that adopts a structure similar to that of cationic amino acid transporters. Molecular docking results showed that XA binds to GEP1 via a pocket similar to the ligand binding sites of known amino acid transporters. In addition, truncations of this N-terminal sequence significantly enhanced the expression, solubility, and stability of GEP1. In addition, we found that GEP1 interacts with GCα via its C-terminal region, which is interrupted by mutations of a few conserved residues. These findings provide further insights into the molecular mechanism for the XA recognition by GEP1 and the activation of the gametogenesis of malaria parasites through GEP1-GCα interaction.
Assuntos
Malária , Parasitos , Animais , Guanilato Ciclase/metabolismo , Parasitos/metabolismo , Simulação de Acoplamento Molecular , Transdução de Sinais , Gametogênese , GMP Cíclico/metabolismo , Malária/parasitologiaRESUMO
M2-type polarization of tumor associated-macrophage (TAM) is involved in the malignancy of gastrointestinal stromal tumor (GIST) progression. ETS variant 1 (ETV1) has been previously validated to regulate GIST pathogenesis. Our study intended to explore the role and mechanism of ETV1 in mediating the M2-polarization of TAM in GIST progression. First, we analyzed the correlation between ETV1 expression and M2-polarization in GIST tissues. IL-4 was used to treat THP-1-derived TAM cells and IL-4-stimulated TAM were co-cultured with GIST-T1 cells to mimic the GIST microenvironment. A loss-of-function assay was performed to explore the role of ETV1. Results showed that ETV1 elevation was positively correlated with M2-polarization. IL-4-induced TAM promoted ETV1 expression, silencing ETV1 inhibited proliferation, invasion and KIT activation in IL-4-treated GIST cells, while cell apoptosis was enhanced. Besides, co-culture of ETV1-silenced GIST cells significantly depressed M2-polarization in TAM, presented as decreased levels of CD206, Agr-1 and cytokines, as well as the proportion of CD206-positive TAM. PDE3A was positively correlated with ETV1 and M2-polarization. Overexpressing PDE3A reversed the inhibitory effects of ETV1 silencing. Generally, ETV1 inhibition depressed M2-polarization of TAM in GIST and its promotion on pathological aggravation via down-regulating PDE3A. This evidence may provide a new target for GIST regulation.
RESUMO
Menin is a tumour suppressor protein whose loss or inactivation causes multiple endocrine neoplasia 1 (MEN1), a hereditary autosomal dominant tumour syndrome that is characterized by tumorigenesis in multiple endocrine organs. Menin interacts with many proteins and is involved in a variety of cellular processes. Menin binds the JUN family transcription factor JUND and inhibits its transcriptional activity. Several MEN1 missense mutations disrupt the menin-JUND interaction, suggesting a correlation between the tumour-suppressor function of menin and its suppression of JUND-activated transcription. Menin also interacts with mixed lineage leukaemia protein 1 (MLL1), a histone H3 lysine 4 methyltransferase, and functions as an oncogenic cofactor to upregulate gene transcription and promote MLL1-fusion-protein-induced leukaemogenesis. A recent report on the tethering of MLL1 to chromatin binding factor lens epithelium-derived growth factor (LEDGF) by menin indicates that menin is a molecular adaptor coordinating the functions of multiple proteins. Despite its importance, how menin interacts with many distinct partners and regulates their functions remains poorly understood. Here we present the crystal structures of human menin in its free form and in complexes with MLL1 or with JUND, or with an MLL1-LEDGF heterodimer. These structures show that menin contains a deep pocket that binds short peptides of MLL1 or JUND in the same manner, but that it can have opposite effects on transcription. The menin-JUND interaction blocks JUN N-terminal kinase (JNK)-mediated JUND phosphorylation and suppresses JUND-induced transcription. In contrast, menin promotes gene transcription by binding the transcription activator MLL1 through the peptide pocket while still interacting with the chromatin-anchoring protein LEDGF at a distinct surface formed by both menin and MLL1.
Assuntos
Proteína de Leucina Linfoide-Mieloide/metabolismo , Proteínas Proto-Oncogênicas c-jun/metabolismo , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas/metabolismo , Transcrição Gênica , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Sítios de Ligação , Cromatina/metabolismo , Cristalografia por Raios X , Fibroblastos , Células HEK293 , Histona-Lisina N-Metiltransferase , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Proteína de Leucina Linfoide-Mieloide/química , Fosforilação , Ligação Proteica , Multimerização Proteica , Proteínas Proto-Oncogênicas c-jun/química , Relação Estrutura-AtividadeRESUMO
The Fanconi anemia protein SLX4 assembles a genome and telomere maintenance toolkit, consisting of the nucleases SLX1, MUS81 and XPF. Although it is known that SLX4 acts as a scaffold for building this complex, the molecular basis underlying this function of SLX4 remains unclear. Here, we report that functioning of SLX4 is dependent on its dimerization via an oligomerization motif called the BTB domain. We solved the crystal structure of the SLX4BTB dimer, identifying key contacts (F681 and F708) that mediate dimerization. Disruption of BTB dimerization abrogates nuclear foci formation and telomeric localization of not only SLX4 but also of its associated nucleases. Furthermore, dimerization-deficient SLX4 mutants cause defective cellular response to DNA interstrand crosslinking agent and telomere maintenance, underscoring the contribution of BTB domain-mediated dimerization of SLX4 in genome and telomere maintenance.
Assuntos
Endonucleases/metabolismo , Recombinases/química , Linhagem Celular , Interações Hidrofóbicas e Hidrofílicas , Mitomicina/toxicidade , Domínios Proteicos , Multimerização Proteica , Recombinases/metabolismo , Telômero/enzimologia , Telômero/ultraestruturaRESUMO
SLX4 assembles a toolkit of endonucleases SLX1, MUS81 and XPF, which is recruited to telomeres via direct interaction of SLX4 with TRF2. Telomeres present an inherent obstacle for DNA replication and repair due to their high propensity to form branched DNA intermediates. Here we provide novel insight into the mechanism and regulation of the SLX4 complex in telomere preservation. SLX4 associates with telomeres throughout the cell cycle, peaking in late S phase and under genotoxic stress. Disruption of SLX4's interaction with TRF2 or SLX1 and SLX1's nuclease activity independently causes telomere fragility, suggesting a requirement of the SLX4 complex for nucleolytic resolution of branched intermediates during telomere replication. Indeed, the SLX1-SLX4 complex processes a variety of telomeric joint molecules in vitro. The nucleolytic activity of SLX1-SLX4 is negatively regulated by telomeric DNA-binding proteins TRF1 and TRF2 and is suppressed by the RecQ helicase BLM in vitro. In vivo, in the presence of functional BLM, telomeric circle formation and telomere sister chromatid exchange, both arising out of nucleolytic processing of telomeric homologous recombination intermediates, are suppressed. We propose that the SLX4-toolkit is a telomere accessory complex that, in conjunction with other telomere maintenance proteins, ensures unhindered, but regulated telomere maintenance.
Assuntos
Recombinases/metabolismo , Telômero/metabolismo , Ciclo Celular , DNA/metabolismo , Endodesoxirribonucleases , Endonucleases/metabolismo , Células HeLa , Recombinação Homóloga , Humanos , RecQ Helicases/metabolismo , Troca de Cromátide Irmã , Proteínas de Ligação a Telômeros/metabolismoRESUMO
Understanding how cellular machinery deals with chromosomal genome complexity is an important question because protein bound to DNA may affect various cellular processes of nucleic acid metabolism. DNA helicases are at the forefront of such processes, yet there is only limited knowledge how they remodel protein-DNA complexes and how these mechanisms are regulated. We have determined that representative human RecQ and Fe-S cluster DNA helicases are potently blocked by a protein-DNA interaction. The Fanconi anemia group J (FANCJ) helicase partners with the single-stranded DNA-binding protein replication protein A (RPA) to displace BamHI-E111A bound to duplex DNA in a specific manner. Protein displacement was dependent on the ATPase-driven function of the helicase and unique properties of RPA. Further biochemical studies demonstrated that the shelterin proteins TRF1 and TRF2, which preferentially bind the telomeric repeat found at chromosome ends, effectively block FANCJ from unwinding the forked duplex telomeric substrate. RPA, but not the Escherichia coli single-stranded DNA-binding protein or shelterin factor Pot1, stimulated FANCJ ejection of TRF1 from the telomeric DNA substrate. FANCJ was also able to displace TRF2 from the telomeric substrate in an RPA-dependent manner. The stimulation of helicase-catalyzed protein displacement is also observed with the DNA helicase RECQ1, suggesting a conserved functional interaction of RPA-interacting helicases. These findings suggest that partnerships between RPA and interacting human DNA helicases may greatly enhance their ability to dislodge proteins bound to duplex DNA, an activity that is likely to be highly relevant to their biological roles in DNA metabolism.
Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , DNA/metabolismo , Proteínas de Grupos de Complementação da Anemia de Fanconi/metabolismo , RecQ Helicases/metabolismo , Proteína de Replicação A/metabolismo , Substituição de Aminoácidos , Sequência de Bases , DNA/química , DNA/genética , Desoxirribonuclease BamHI/metabolismo , Exodesoxirribonucleases/metabolismo , Humanos , Substâncias Macromoleculares/química , Substâncias Macromoleculares/metabolismo , Conformação de Ácido Nucleico , Ligação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteína de Replicação A/genética , Especificidade por Substrato , Proteína 1 de Ligação a Repetições Teloméricas/metabolismo , Helicase da Síndrome de WernerRESUMO
The DNA damage checkpoint is a highly conserved signaling pathway induced by genotoxin exposure or endogenous genome stress. It alters many cellular processes such as arresting the cell cycle progression and increasing DNA repair capacities. However, cells can downregulate the checkpoint after prolonged stress exposure to allow continued growth and alternative repair. Strategies that can dampen the DNA damage checkpoint are not well understood. Here, we report that budding yeast employs a pathway composed of the scaffold protein Rtt107, its binding partner Mms22, and an Mms22-associated ubiquitin ligase complex to downregulate the DNA damage checkpoint. Mechanistically, this pathway promotes the proteasomal degradation of a key checkpoint factor, Rad9. Furthermore, Rtt107 binding to Mms22 helps to enrich the ubiquitin ligase complex on chromatin and target the chromatin-bound form of Rad9. Finally, we provide evidence that the Rtt107-Mms22 axis operates in parallel with the Rtt107-Slx4 axis, which displaces Rad9 from chromatin. We thus propose that Rtt107 enables a bifurcated "anti-Rad9" strategy to optimally downregulate the DNA damage checkpoint.
RESUMO
Identifying new targets for overcoming radioresistance is crucial for improving the efficacy of lung cancer radiotherapy, given that tumor cell resistance is a leading cause of treatment failure. Recent research has spotlighted the significance of Musashi2 (MSI2) in cancer biology. In this study, we first demonstrated that MSI2 plays a key function in regulating the radiosensitivity of lung cancer. The expression of MSI2 is negatively correlated with overall survival in cancer patients, and the knockdown of MSI2 inhibits tumorigenesis and increases radiosensitivity of lung cancer cells. Cellular radiosensitivity, which is closely linked to DNA damage, is influenced by MSI2 interaction with ataxia telangiectasia mutated and Rad3-related kinase (ATR) and checkpoint kinase 1 (CHK1) post-irradiation; moreover, knockdown of MSI2 inhibits the ATR-mediated DNA damage response pathway. RNA-binding motif protein 17 (RBM17), which is implicated in DNA damage repair, exhibits increased interaction with MSI2 post-irradiation. We found that knockdown of RBM17 disrupted the interaction between MSI2 and ATR post-irradiation and increased the radiosensitivity of lung cancer cells. Furthermore, we revealed the potential mechanism of MSI2 recruitment into the nucleus with the assistance of RBM17 to activate ATR to promote radioresistance. This study provides novel insights into the potential application of MSI2 as a new target in lung cancer radiotherapy.
RESUMO
Ash2L is a core component of the MLL family histone methyltransferases and has an important role in regulating the methylation of histone H3 on lysine 4. Here, we report the crystal structure of the N-terminal domain of Ash2L and reveal a new function of Ash2L. The structure shows that Ash2L contains an atypical PHD finger that does not have histone tail-binding activity. Unexpectedly, the structure shows a previously unrecognized winged-helix motif that directly binds to DNA. The DNA-binding-deficient mutants of Ash2L reduced Ash2L localization to the HOX locus. Strikingly, a single mutation in Ash2L(WH) (K131A) breaks the chromatin domain boundary, suggesting that Ash2L also has a role in chromosome demarcation.
Assuntos
Motivos de Aminoácidos , Proteínas de Ligação a DNA/química , Proteínas Nucleares/química , Fatores de Transcrição/química , Fatores de Transcrição Winged-Helix/química , Sequência de Aminoácidos , Cromatina/metabolismo , Cristalografia por Raios X , DNA/química , DNA/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Loci Gênicos , Histonas/metabolismo , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Mutação , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Estrutura Terciária de Proteína , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição Winged-Helix/genética , Fatores de Transcrição Winged-Helix/metabolismoRESUMO
PTPN4 is a widely expressed non-receptor protein tyrosine phosphatase. Although its overexpression inhibits cell growth, the proteins with which it interacts to regulate cell growth are unknown. In this study, we identified CrkI as a PTPN4-interacting protein using a yeast two-hybrid, and confirmed this interaction using in vitro GST pull-down and co-immunoprecipitation and co-localization assays. We further determined the interactional regions as the SH3 domain of CrkI and the proline-rich region between amino acids 462 and 468 of PTPN4. Notably, overexpression of PTPN4 inhibits CrkI-mediated proliferation and wound healing of HEK293T cells, while knockdown of PTPN4 by siRNA in Hep3B cells enhances CrkI-mediated cell growth and motility. Moreover, our data show that ectopic expression of PTPN4 reduces the phosphorylation level of CrkI in HEK293T cells. These findings suggest that PTPN4 negatively regulates cell proliferation and motility through dephosphorylation of CrkI.
Assuntos
Proteína Tirosina Fosfatase não Receptora Tipo 4/metabolismo , Proteínas Proto-Oncogênicas c-crk/metabolismo , Sequência de Aminoácidos , Movimento Celular , Proliferação de Células , Técnicas de Silenciamento de Genes , Células HEK293 , Células HeLa , Humanos , Dados de Sequência Molecular , Fosforilação , Ligação Proteica , Mapeamento de Interação de Proteínas , Estrutura Terciária de Proteína , Proteína Tirosina Fosfatase não Receptora Tipo 4/química , Interferência de RNA , Reprodutibilidade dos TestesRESUMO
Elevated expression and genetic aberration of IRTKS, also named as BAIAP2L1, have been observed in many tumors, especially in tumor progression. however, the molecular and cellular mechanisms involved in the IRTKS-enhanced tumor progression are obscure. Here we show that higher IRTKS level specifically increases histone H3 lysine 9 trimethylation (H3K9me3) by promoting accumulation of the histone methyltransferase SETDB1. Furthermore, we reveal that IRTKS recruits the deubiquitinase OTUD4 to remove Lys48-linked polyubiquitination at K182/K1050 sites of SETDB1, thus blocking SETDB1 degradation via the ubiquitin-proteasome pathway. Interestingly, the enhanced IRTKS-OTUD4-SETDB1-H3K9me3 axis leads to a general decrease in chromatin accessibility, which inhibits transcription of CDH1 encoding E-cadherin, a key molecule essential for maintaining epithelial cell phenotype, and therefore results in epithelial-mesenchymal transition (EMT) and malignant cell metastasis. Clinically, the elevated IRTKS levels in tumor specimens correlate with SETDB1 levels, but negatively associate with survival time. Our data reveal a novel mechanism for the IRTKS-enhanced tumor progression, where IRTKS cooperates with OTUD4 to enhance SETDB1-mediated H3K9 trimethylation that promotes tumor metastasis via suppressing E-cadherin expression. This study also provides a potential approach to reduce the activity and stability of the known therapeutic target SETDB1 possibly through regulating IRTKS or deubiquitinase OTUD4.
RESUMO
Lysine acetyltransferase 7 (KAT7) was upregulated in gastric cancer (GC) patient tissues, and associated with poor prognosis and metastasis. However, its specific role in GC remains unclear. This study aimed to annotate the role of KAT7 in GC cells. The results showed that the overexpression of KAT7 promoted cell growth, migration, and invasion, while KAT7 inhibition has the opposite effect. Besides, KAT7 participated in cell cycle phase distribution and epithelial-mesenchymal transition (EMT) process of GC cells. In addition, KAT7 promoted the transcription and nuclear translocation of Yes-associated protein 1 (YAP1) in MKN45 cells. Silence of YAP1 partly reversed the promoting effect of KAT7 on GC cells progression. In summary, this study indicates that KAT7 promoted GC cells progression through promoting YAP1 activation, contributes to understand the specific role of KAT7 in GC.
Assuntos
Lisina Acetiltransferases , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/patologia , Proteínas de Sinalização YAP , Movimento Celular , Regulação Neoplásica da Expressão Gênica/genética , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal , Proliferação de Células , Lisina Acetiltransferases/metabolismo , Histona AcetiltransferasesRESUMO
In this paper, a method of ball milling and sieving is proposed for recovery of high-grade copper from waste printed circuit boards (WPCBs). The effects of the milling time on the metals grade and recovery of the Cu, Sn and Pb during mechanical treatment were investigated. The results showed that, after 3 cycles of ball milling and sieving, the content of Cu was enriched to 94.72â wt.% from the initial 74.22â wt.% with a high recovery rate of 86.78%. Moreover, the contents of Sn and Pb were enriched to 28.27 wt.% and 18.86â wt.% from 10.13â wt.% and 6.63â wt.% in the by-products, respectively. However, excessive grinding occurred when the milling time was longer than 3 h and led to a sharp decrease in Cu recovery. The X-ray diffraction (XRD) patterns indicated that the metal phases mainly comprised pure Cu, Sn, Pb in the WPCB particles, while a Cu-Sn alloy was formed during the milling process, and the Cu-Sn alloy was also enriched in the tailings. The results presented here establish that ball milling and sieving is an alternative approach to recovering high-grade copper from WPCBs.
Assuntos
Cobre , Resíduo Eletrônico , Metais , Reciclagem , Difração de Raios XRESUMO
Telomerase is crucial for telomere maintenance and genome integrity. The most salient feature of Tetrahymena telomerase is that its CST subcomplex (p75-p45-p19) is tethered to the telomerase catalytic core by interacting with the hub p50. Although the cryoelectron microscopy (cryo-EM) structures of Tetrahymena telomerase have recently been reported, the mechanisms of how and why p50 bridges the CST subcomplex to the telomerase catalytic core remain unclear. Here, we present the nuclear magnetic resonance (NMR) structure of the p75OB1-p50PBM complex. Loss of the interaction between p75 and p50 detaches the CST subcomplex from the telomerase catalytic core in Tetrahymena. The tethering of the CST subcomplex to telomerase is required for telomere homeostasis. However, the detached CST subcomplex is still capable of facilitating the telomeric complementary-strand (C-strand) fill in similar to the non-tethered CST complexes in other organisms. These results expand our understanding of telomere synthesis in Tetrahymena.
Assuntos
Telomerase , Tetrahymena thermophila , Microscopia Crioeletrônica , Telômero , Domínio CatalíticoRESUMO
The epigenetic dysregulation of tumor suppressor genes plays an important role in many cancers, including hepatocellular carcinoma (HCC). In this study, we identified a new gene, family with sequence similarity 43, member B (FAM43B), based on a previous genome-wide approach. FAM43B was significantly downregulated in 60% (24/40) HCC specimens as compared to non-HCC livers. Enforced FAM43B overexpression could suppress cell growth and colony formation in vitro, and induce cell cycle delay, whereas FAM43B knockdown enhanced cell growth. The expression level of FAM43B was found related to the methylation level of FAM43B promoter in HCC cell lines and HCC specimens. The collective data suggest that the expression of FAM43B was regulated by methylation and the epigenetic silencing of FAM43B could contribute to HCC tumorigenesis by regulating cell proliferation.
Assuntos
Carcinoma Hepatocelular/genética , Proliferação de Células , Metilação de DNA , Epigênese Genética , Genes Supressores de Tumor , Neoplasias Hepáticas/genética , Carcinoma Hepatocelular/metabolismo , Ciclo Celular/genética , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/metabolismo , Especificidade de Órgãos , Filogenia , Regiões Promotoras Genéticas , Interferência de RNARESUMO
Proliferation of liver cells can be observed in hepatocarcinogenesis, at different stages of liver development, and during liver regeneration after an injury. Does it imply that they share similar molecular mechanisms? Here, the transcriptional profiles of hepatocellular carcinoma (HCC), liver development, and liver regeneration were systematically compared as a preliminary attempt to answer this question. From the comparison, we found that advanced HCC mimics early development in terms of deprived normal liver functions and activated cellular proliferation, but advanced HCC and early development differ in expressions of cancer-related genes and their transcriptional controls. HCC and liver regeneration demonstrate different expression patterns as a whole, but regeneration is similar to dysplasia (pre-stage of HCC) in terms of their proximity to the normal state. In summary, of these three important processes, the carcinogenic progress carries the highest variance in expression; HCC pre-stage shares some resemblance with liver regeneration; and advanced HCC stage displays similarity with early development.