RESUMO
The nuclear pore complex (NPC) is a huge protein complex embedded in the nuclear envelope. It has central functions in nucleocytoplasmic transport, nuclear framework, and gene regulation. Nucleoporin 107 kDa (NUP107) is a component of the NPC central scaffold and is an essential protein in all eukaryotic cells. Here, we report on biallelic NUP107 mutations in nine affected individuals who are from five unrelated families and show early-onset steroid-resistant nephrotic syndrome (SRNS). These individuals have pathologically focal segmental glomerulosclerosis, a condition that leads to end-stage renal disease with high frequency. NUP107 is ubiquitously expressed, including in glomerular podocytes. Three of four NUP107 mutations detected in the affected individuals hamper NUP107 binding to NUP133 (nucleoporin 133 kDa) and NUP107 incorporation into NPCs in vitro. Zebrafish with nup107 knockdown generated by morpholino oligonucleotides displayed hypoplastic glomerulus structures and abnormal podocyte foot processes, thereby mimicking the pathological changes seen in the kidneys of the SRNS individuals with NUP107 mutations. Considering the unique properties of the podocyte (highly differentiated foot-process architecture and slit membrane and the inability to regenerate), we propose a "podocyte-injury model" as the pathomechanism for SRNS due to biallelic NUP107 mutations.
Assuntos
Idade de Início , Mutação/genética , Síndrome Nefrótica/congênito , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Proteínas de Peixe-Zebra/genética , Peixe-Zebra/genética , Alelos , Animais , Células Cultivadas , Criança , Pré-Escolar , Citoplasma/metabolismo , Feminino , Haplótipos , Humanos , Immunoblotting , Imunoprecipitação , Lactente , Rim/metabolismo , Rim/patologia , Masculino , Microscopia de Fluorescência , Síndrome Nefrótica/etiologia , Síndrome Nefrótica/patologia , Poro Nuclear , Complexo de Proteínas Formadoras de Poros Nucleares/antagonistas & inibidores , Oligorribonucleotídeos Antissenso/farmacologia , Linhagem , Podócitos/metabolismo , Podócitos/patologia , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Peixe-Zebra/crescimento & desenvolvimento , Proteínas de Peixe-Zebra/antagonistas & inibidoresRESUMO
Lamin B receptor (LBR), an inner nuclear membrane (INM) protein, contributes to the functional integrity of the nucleus by tethering heterochromatin to the nuclear envelope. We have previously reported that the depletion of embryonic large molecule derived from yolk sac (ELYS; also known as AHCTF1), a component of the nuclear pore complex, from cells perturbs the localization of LBR to the INM, but little is known about the underlying molecular mechanism. In this study, we found that the depletion of ELYS promoted LBR phosphorylation at the residues known to be phosphorylated by cyclin-dependent kinase (CDK) and serine/arginine protein kinases 1 and 2 (SRPK1 and SRPK2, respectively). These phosphorylation events were most likely to be counter-balanced by protein phosphatase 1 (PP1), and the depletion of PP1 from cells consistently caused the mislocalization of LBR. These observations point to a new mechanism regulating the localization of LBR, which is governed by an ELYS-mediated phosphorylation network. This phosphorylation-dependent coordination between INM proteins and the nuclear pore complex might be important for the integrity of the nucleus.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Sequência de Aminoácidos , Proteína Quinase CDC2/metabolismo , Homólogo 5 da Proteína Cromobox , Proteínas Cromossômicas não Histona/metabolismo , Células HEK293 , Células HeLa , Histonas/metabolismo , Humanos , Lamina Tipo B/metabolismo , Mutação/genética , Membrana Nuclear/metabolismo , Proteínas Nucleares/metabolismo , Fosforilação , Domínios Proteicos , Isoformas de Proteínas/metabolismo , Proteína Fosfatase 1/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Transporte Proteico , Receptores Citoplasmáticos e Nucleares/química , Receptor de Lamina BRESUMO
Many functional subdomains, including promyelocytic leukemia nuclear bodies (PML NBs), are formed in the mammalian nucleus. Various proteins are constitutively or transiently accumulated in PML NBs in a PML-dependent manner. MORC3 (microrchidia family CW-type zinc-finger 3), also known as NXP2, which consists of GHL-ATPase, a CW-type zinc-finger and coiled-coil domains, is localized in PML NBs, where it recruits and activates p53 to induce cellular senescence. Interestingly, we found that MORC3 can form PML-independent nuclear domains (NDs) in mouse hematopoietic cells and even in Pml-deficient cells. Here, we show that MORC3 colocalizes with PML by a two-step molecular mechanism: the PML-independent formation of MORC3 NDs by the ATPase cycle, and the association of MORC3 with PML via the SUMO1-SUMO-interacting motif (SIM). Similarly to other members of the GHL-ATPase family, MORC3 functions as a 'molecular clamp'. ATP binding induces conformational changes in MORC3, leading to the formation of MORC3 NDs, and subsequent ATP hydrolysis mediates the diffusion and binding of MORC3 to the nuclear matrix. MORC3 might clamp DNA or nucleosomes in MORC3 NDs via the CW domain. Furthermore, the SUMOylation of MORC3 at five sites was involved in the association of MORC3 with PML, and SUMO1-unmodified MORC3 formed NDs independently of PML.
Assuntos
Adenosina Trifosfatases/metabolismo , Proteínas de Ligação a DNA/metabolismo , Corpos de Inclusão Intranuclear/metabolismo , Proteínas Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Adenosina Trifosfatases/química , Adenosina Trifosfatases/genética , Animais , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/genética , Células HeLa , Humanos , Corpos de Inclusão Intranuclear/química , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/metabolismo , Camundongos , Proteínas Nucleares/genética , Proteína da Leucemia Promielocítica , Estrutura Terciária de Proteína , Transporte Proteico , Proteína SUMO-1/genética , Proteína SUMO-1/metabolismo , Fatores de Transcrição/genética , Proteínas Supressoras de Tumor/genéticaRESUMO
INTRODUCTION: Automobiles carrying an autonomous emergency braking system (AEBS) are currently prevailing. While the reduction of traffic accidents is expected because of the widespread use of the system, concerns as regards many drivers using the system without proper understanding of the trigger conditions (TCs) have arisen. This research aims to grasp the degree of recognition of the AEBS TCs by a driver with a vehicle equipped with the system. METHOD: Using a web research company, we sent a survey sheet for screening to 9999 monitors randomly selected by gender and age group and confirmed own vehicle with an autonomous braking system ownership status. The number of answer targets was 200 for each of the four groups divided by age and gender. In this research, we developed a multivariate analysis model with the degree of understanding the AEBS TCs as the objective variable. The explanatory variables of this model were "Driver characteristics" and "Contact opportunities of information on the AEBS." RESULTS: Using PCA's main component scores as the objective variable, two types of multiple regression models were constructed according to the AEBS TCs (do not work properly and work accidentally). The model analysis showed that gender, age, confidence in driving skill, and experience of the AEBS before purchasing are significant variables in both models. The recognition of the conditions of the "AEBS does not work properly" was influenced by the information-gathering ability and the degree of reference to various information. In contrast, the recognition of the conditions of the "AEBS work accidentally" was influenced by the interest of automobiles, such as the importance of automobile for self-expression and explanation taken up in a car magazine. CONCLUSIONS: This study clarified the driver characteristics and contact opportunities of information that have problems in recognizing the AEBS TCs. Practical Applications: Considering measures, such as public relations, utilizing this result will be meaningful in terms of road safety in the current stage, which is the transitional period of the AEBS.
Assuntos
Acidentes de Trânsito/prevenção & controle , Automação , Condução de Veículo , Equipamentos de Proteção/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
This paper reports on the development and evaluation of various probes consisting of silicon cantilevers with different types of tips made of platinum, ruthenium, chromium and conductive CVD diamond for probe-based ultrahigh density ferroelectric data storage. Using the metal-tip probes, data bits on a medium can be written and read with contact operation. Durability experiments of the various tips against a ferroelectric material are performed. The most detrimental tip wear occurred for platinum, while wear was much less apparent for the remaining tips. Reading and writing experiments on an LiTaO(3) plate are also performed on the basis of scanning nonlinear dielectric microscopy using ruthenium- and chromium-tip probes.
RESUMO
Arynes were found to insert into carbon-halogen sigma-bonds of various acid halides, enabling acyl and halogen moieties to be introduced simultaneously into adjacent positions of aromatic rings.
RESUMO
Nuclear pore complexes (NPCs) maintain cellular homeostasis by mediating nucleocytoplasmic transport. Although cyclin-dependent kinases (CDKs) regulate NPC assembly in interphase, the location of NPC assembly on the nuclear envelope is not clear. CDKs also regulate the disappearance of pore-free islands, which are nuclear envelope subdomains; this subdomain gradually disappears with increase in homogeneity of the NPC in response to CDK activity. However, a causal relationship between pore-free islands and NPC assembly remains unclear. Here, we elucidated mechanisms underlying NPC assembly from a new perspective by focusing on pore-free islands. We proposed a novel framework for image-based analysis to automatically determine the detailed 'landscape' of pore-free islands from a large quantity of images, leading to the identification of NPC intermediates that appear in pore-free islands with increased frequency in response to CDK activity. Comparison of the spatial distribution between simulated and the observed NPC intermediates within pore-free islands showed that their distribution was spatially biased. These results suggested that the disappearance of pore-free islands is highly related to de novo NPC assembly and indicated the existence of specific regulatory mechanisms for the spatial arrangement of NPC assembly on nuclear envelopes.
Assuntos
Quinases Ciclina-Dependentes/metabolismo , Poro Nuclear/metabolismo , Transporte Ativo do Núcleo Celular/fisiologia , Animais , Linhagem Celular Tumoral , Células HeLa , Humanos , Glicoproteínas de Membrana/metabolismo , Membrana Nuclear/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , RatosRESUMO
In metazoans with "open" mitosis, cells undergo structural changes involving the complete disassembly of the nuclear envelope (NE). In post-mitosis, the dividing cell faces the difficulty to reassemble NE structures in a highly regulated fashion around separated chromosomes. The de novo formation of nuclear pore complexes (NPCs), which are gateways between the cytoplasm and nucleoplasm across the nuclear membrane, is an archetype of macromolecular assembly and is therefore of special interest. The reformation of a functional NE further involves the reassembly and organization of other NE components, the nuclear membrane and NE proteins, around chromosomes in late mitosis. Here, we discuss the function of NE components, such as lamins and INM proteins, in NE reformation and highlight recent results on coordination of NPC and NE assembly.
Assuntos
Mitose/genética , Membrana Nuclear/genética , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Poro Nuclear/genética , Núcleo Celular/genética , Núcleo Celular/metabolismo , Cromossomos/genética , Citoplasma/genética , Citoplasma/metabolismo , Humanos , Laminas/genética , Laminas/metabolismo , Membrana Nuclear/metabolismo , Poro Nuclear/metabolismo , Complexo de Proteínas Formadoras de Poros Nucleares/genéticaRESUMO
In open mitosis the nuclear envelope (NE) reassembles at the end of each mitosis. This process involves the reformation of the nuclear pore complex (NPC), the inner and outer nuclear membranes, and the nuclear lamina. In human cells cell cycle-dependent NE subdomains exist, characterized as A-type lamin-rich/NPC-free or B-type lamin-rich/NPC-rich, which are initially formed as core or noncore regions on mitotic chromosomes, respectively. Although postmitotic NE formation has been extensively studied, little is known about the coordination of NPC and NE assembly. Here, we report that the nucleoporin ELYS/Mel28, which is crucial for postmitotic NPC formation, is essential for recruiting the lamin B receptor (LBR) to the chromosomal noncore region. Furthermore, ELYS/Mel28 is responsible for focusing of A-type lamin-binding proteins like emerin, Lap2α and the barrier-to-autointegration factor (BAF) at the chromosomal core region. ELYS/Mel28 biochemically interacts with the LBR in a phosphorylation-dependent manner. Recruitment of the LBR depends on the nucleoporin Nup107, which interacts with ELYS/Mel28 but not on nucleoporin Pom121, suggesting that the specific molecular interactions with ELYS/Mel28 are involved in the NE assembly at the noncore region. The depletion of the LBR affected neither the behavior of emerin nor Lap2α indicating that the recruitment of the LBR to mitotic chromosomes is not involved in formation of the core region. The depletion of ELYS/Mel28 also accelerates the entry into cytokinesis after recruitment of emerin to chromosomes. Our data show that ELYS/Mel28 plays a role in NE subdomain formation in late mitosis.