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nuclear pore

Zhengqian Li, Cheng Ni, Chun Xia, Joey Jaw, Yujie Wang, Yiyun Cao, Mao Xu, Xiangyang Guo
It is known that inhaled anesthetics induce neuroinflammation and facilitate postoperative cognitive dysfunction (POCD) in aged individuals; however, the mechanisms by which they mediate these effects remain elusive. Inhalation of the isoflurane anesthetic leads to opening of the mitochondrial permeability transition pore and loss of mitochondrial membrane potential. Therefore, mitochondrial retrograde signaling, which is an adaptive mechanism that facilitates the transmission of signals from dysfunctional mitochondria to the nucleus to activate target gene expression, may be activated during isoflurane inhalation...
November 24, 2016: Molecular Medicine Reports
Kazunari Iwamoto, Yuki Shindo, Koichi Takahashi
Cellular heterogeneity, which plays an essential role in biological phenomena, such as drug resistance and migration, is considered to arise from intrinsic (i.e., reaction kinetics) and extrinsic (i.e., protein variability) noise in the cell. However, the mechanistic effects of these types of noise to determine the heterogeneity of signal responses have not been elucidated. Here, we report that the output of epidermal growth factor (EGF) signaling activity is modulated by cellular noise, particularly by extrinsic noise of particular signaling components in the pathway...
November 2016: PLoS Computational Biology
Rebecca Smith, Iñigo J Vitórica-Yrezábal, Adrian Hill, Lee Brammer
A metal-organic framework (MOF) with one-dimensional channels of approximately hexagonal cross-section [Ag2(O2CCF2CF2CO2)(TMP)] 1: (TMP =2,3,5,6-tetramethylpyrazine) has been synthesized with MeOH filling the channels in its as-synthesized form as [Ag2(O2CCF2CF2CO2)(TMP)]·n(MeOH) 1-MEOH: (n = 1.625 by X-ray crystallography). The two types of ligand connect columns of Ag(I) centres in an alternating manner, both around the channels and along their length, leading to an alternating arrangement of hydrocarbon (C-H) and fluorocarbon (C-F) groups lining the channel walls, with the former groups projecting further into the channel than the latter...
January 13, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Yi Ning
Chromosome translocations leading to gene fusions have emerged as important oncogenic drivers of various types of malignancies. Detection and characterization of these fusion genes not only help diagnosis and management of specific malignancies, but also contribute to our understanding of the genetic basis and pathogenesis of these diseases. NUP98 gene encodes a 98 kDa nucleoporin, which is a component of the nuclear pore complex that mediates transport of mRNA and proteins between the nucleus and the cytoplasm...
December 2016: Best Practice & Research. Clinical Haematology
Xiwei Yu, Jiahui Hou, Yijie Shi, Chang Su, Liang Zhao
It is well known that most anticancer drugs commonly show high toxicity to the DNA of tumor cells and exert effects by combining with the DNA or associated enzymes in the nucleus. Most developed drugs are first delivered into the cytoplasm and then transferred to the nucleus through the membrane pores. Sometimes, the transportation of drugs from cytoplasm to nucleus is not efficient and often results in poor therapeutic effects. In this study, we developed special and novel nanoparticles (NPs) made of chitosan and protamine for targeted nuclear capture of drugs to enhance anticancer effects...
2016: International Journal of Nanomedicine
Arun Devaraj, Murugesan Vijayakumar, Jie Bao, Mond F Guo, Miroslaw A Derewinski, Zhijie Xu, Michel J Gray, Sebastian Prodinger, Karthikeyan K Ramasamy
The formation of carbonaceous deposits (coke) in zeolite pores during catalysis leads to temporary deactivation of catalyst, necessitating regeneration steps, affecting throughput, and resulting in partial permanent loss of catalytic efficiency. Yet, even to date, the coke molecule distribution is quite challenging to study with high spatial resolution from surface to bulk of the catalyst particles at a single particle level. To address this challenge we investigated the coke molecules in HZSM-5 catalyst after ethanol conversion treatment by a combination of C K-edge X-ray absorption spectroscopy (XAS), (13)C Cross polarization-magic angle spinning nuclear magnetic resonance (CP-MAS NMR) spectroscopy, and atom probe tomography (APT)...
November 23, 2016: Scientific Reports
Alejandro Gozalo, Maya Capelson
Knowing the configuration of the nuclear pore is essential for appreciating the underlying mechanisms of nucleo-cytoplasmic communication. Now, Fernandez-Martinez et al. present a high-resolution structure of the cytoplasmic nuclear pore-mRNA export holo-complex, challenging our textbook depiction of this massive membrane-embedded complex.
November 17, 2016: Cell
Asfar S Azmi, Ramzi M Mohammad
No abstract text is available yet for this article.
December 2016: Journal of Clinical Oncology: Official Journal of the American Society of Clinical Oncology
Marion Weberruss, Wolfram Antonin
The nucleus is enclosed by the nuclear envelope, a double membrane which creates a selective barrier between the cytoplasm and the nuclear interior. Its barrier and transport characteristics are determined by nuclear pore complexes (NPCs) that are embedded within the nuclear envelope, and control molecular exchange between the cytoplasm and nucleoplasm. In this Commentary, we discuss the biogenesis of these huge protein assemblies from approximately one thousand individual proteins. We will summarize current knowledge about distinct assembly modes in animal cells that are characteristic for different cell cycle phases and their regulation...
November 17, 2016: Journal of Cell Science
Tsung-Hsuan Lai, Ying-Yu Wu, Ya-Yun Wang, Mei-Feng Chen, Pei Wang, Tsung-Ming Chen, Yi-No Wu, Han-Sun Chiang, Pao-Lin Kuo, Ying-Hung Lin
Male factor infertility accounts for approximately 50 percent of infertile couples. The male factor-related causes of intracytoplasmic sperm injection failure include the absence of sperm, immotile sperm, immature sperm, abnormally structured sperm, and sperm with nuclear damage. Our knockout and knock-in mice models demonstrated that SEPTIN12 (SEPT12) is vital for the formation of sperm morphological characteristics during spermiogenesis. In the clinical aspect, mutated SEPT12 in men results in oligozoospermia or teratozoospermia or both...
November 16, 2016: International Journal of Molecular Sciences
Ryan T Behrens, Mounavya Aligeti, Ginger M Pocock, Christina A Higgins, Nathan M Sherer
: HIV-1's Rev protein forms a homooligomeric adaptor complex linking viral RNAs to the cellular CRM1/Ran-GTP nuclear export machinery through the activity of Rev's prototypical leucine-rich nuclear export signal (NES). In this study we used a functional fluorescently-tagged Rev fusion protein as a platform to study the effects of modulating Rev NES identity, number, position, or strength on Rev subcellular trafficking, viral RNA nuclear export, and infectious virion production. We found Rev activity to be remarkably tolerant of diverse NES sequences including supraphysiological NES (SNES) peptides that otherwise arrest CRM1 transport complexes at nuclear pores...
November 16, 2016: Journal of Virology
Alicia K Friedman, Lane A Baker
Synthetic hydrogels were utilized to explore influence of both charge and phenylalanine-glycine (FG) repeat concentration on translocation of select proteins. Hydrogels studied represent a biomimetic platform of the nuclear pore complex (NPC) found in eukaryotic cells. Polyacrylamide/phenylalanine-serine-phenylalanine-glycine (FSFG) peptide copolymers have previously demonstrated similar selectivity to native NPCs. Entry of a nuclear transport receptor (Impβ) into hydrogels was monitored with fluorescence microscopy and observed to be greater within gels that contained larger concentrations of FG peptide...
November 16, 2016: Soft Matter
Helene Andersen, Ladan Parhamifar, A Christy Hunter, Victor Shahin, S Moein Moghimi
It has been questioned as to whether polyplexes in the cytoplasm can reach the nuclear compartment and if so in what form. By applying atomic force microscopy (AFM) to the nuclear envelope and the nuclear pore complexes, we demonstrate that disposition of polyethylenimine (PEI)/DNA polyplexes that were microinjected into the oocytes of Xenopus laevis, as an example of a non-dividing cell, is exclusive to the nuclear pore complex (NPC). AFM images show NPCs clogged only with sub-50nm polyplexes. This mode of disposition neither altered the morphology/integrity of the nuclear membrane nor the NPC...
November 11, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
Zbigniew Korwek, Karolina Tudelska, Paweł Nałęcz-Jawecki, Maciej Czerkies, Wiktor Prus, Joanna Markiewicz, Marek Kochańczyk, Tomasz Lipniacki
BACKGROUND: Importins and exportins influence gene expression by enabling nucleocytoplasmic shuttling of transcription factors. A key transcription factor of innate immunity, NF-κB, is sequestered in the cytoplasm by its inhibitor, IκBα, which masks nuclear localization sequence of NF-κB. In response to TNFα or LPS, IκBα is degraded, which allows importins to bind NF-κB and shepherd it across nuclear pores. NF-κB nuclear activity is terminated when newly synthesized IκBα enters the nucleus, binds NF-κB and exportin which directs the complex to the cytoplasm...
November 11, 2016: Biology Direct
Renjie Wang, Alain Kamgoue, Christophe Normand, Isabelle Léger-Silvestre, Thomas Mangeat, Olivier Gadal
How does the spatial organization of the genome depend on the nuclear shape is unknown, mostly because accurate nuclear size and shape measurement is technically challenging. In large cell populations of the yeast Saccharomyces cerevisiae, we assessed the geometry (size and shape) of nuclei in three dimensions (3D) with a resolution of 30 nm. We improved an automated fluorescent localization method by implementing a post-acquisition correction of the spherical microscopic aberration along the Z-axis, to detect the three dimensional (3D) positions of nuclear pore complexes (NPCs) in the nuclear envelope (NE)...
November 9, 2016: Journal of Cell Science
Doortje Borrenberghs, Lieve Dirix, Flore De Wit, Susana Rocha, Jolien Blokken, Stéphanie De Houwer, Rik Gijsbers, Frauke Christ, Johan Hofkens, Jelle Hendrix, Zeger Debyser
Nuclear entry is a selective, dynamic process granting the HIV-1 pre-integration complex (PIC) access to the chromatin. Classical analysis of nuclear entry of heterogeneous viral particles only yields averaged information. We now have employed single-virus fluorescence methods to follow the fate of single viral pre-integration complexes (PICs) during infection by visualizing HIV-1 integrase (IN). Nuclear entry is associated with a reduction in the number of IN molecules in the complexes while the interaction with LEDGF/p75 enhances IN oligomerization in the nucleus...
November 10, 2016: Scientific Reports
M M Kurshakova, S G Georgieva, D V Kopytova
The molecular mechanisms that coordinate transcription, processing, mRNP assembly, and mRNA export from the nucleus through nuclear pores into the cytoplasm have been the focus of intense research in recent years. Data demonstrating a tight association between the processes involved in gene expression are considered. The main protein complexes that play a role in mRNA export are described. The complexes are recruited to mRNA at steps preceding the mRNA export. The functions that the complexes perform at particular steps of gene expression are analyzed, and protein complexes responsible for quality control of mRNP discussed...
September 2016: Molekuliarnaia Biologiia
Jackson R Roberts, Raphael Orelis-Ribeiro, Binh T Dang, Kenneth M Halanych, Stephen A Bullard
Coeuritrema Mehra, 1933, previously regarded as a junior subjective synonym of Hapalorhynchus Stunkard, 1922, herein is revised to include Coeuritrema lyssimus Mehra, 1933 (type species), Coeuritrema rugatus (Brooks et Sullivan, 1981) comb. n., and Coeuritrema platti Roberts et Bullard sp. n. These genera are morphologically similar by having a ventral sucker, non-fused caeca, two testes, a pre-testicular cirrus sac, an intertesticular ovary, and a common genital pore that opens dorsally and in the sinistral half of the body...
September 6, 2016: Folia Parasitologica
Viola Nähse, Liliane Christ, Harald Stenmark, Coen Campsteijn
Cytokinesis is the final stage of cell division and is concluded by abscission of the intercellular bridge to physically separate the daughter cells. Timing of cytokinetic abscission is monitored by a molecular machinery termed the abscission checkpoint. This machinery delays abscission in cells with persistent chromatin in the intercellular bridge. Recent work has also uncovered its response to high membrane tension, nuclear pore defects, and DNA replication stress. Although it is known that the abscission checkpoint depends on persistent activity of the Aurora B protein kinase, we have only recently begun to understand its molecular basis...
October 31, 2016: Trends in Cell Biology
Arkaitz Ibarra, Chris Benner, Swati Tyagi, Jonah Cool, Martin W Hetzer
The organization of the genome in the three-dimensional space of the nucleus is coupled with cell type-specific gene expression. However, how nuclear architecture influences transcription that governs cell identity remains unknown. Here, we show that nuclear pore complex (NPC) components Nup93 and Nup153 bind superenhancers (SE), regulatory structures that drive the expression of key genes that specify cell identity. We found that nucleoporin-associated SEs localize preferentially to the nuclear periphery, and absence of Nup153 and Nup93 results in dramatic transcriptional changes of SE-associated genes...
October 15, 2016: Genes & Development
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