nuclear pores Dotaz Zobrazit nápovědu
The effects of acoustic waves on membrane structures, and any resulting consequences of this treatment on membrane subunit structures, remain poorly understood, as are the principals of related clinical effects. With a focus on morphological changes in the nuclear envelope, the current study presents detailed observations of membrane structures exposed to therapeutic ultrasound. Ultrasound treatment most commonly resulted in distinct changes in the distribution of nuclear pore complexes (NPCs) and mean NPC number per unit area after 30 min of repair, as well as alterations in NPC diameters on the protoplasmic face of fractured nuclear membranes after 10 min of repair. The greatest effects of ultrasound on nuclear envelope structure and NPCs were not to appear immediately, but became evident after repair processes were initiated. Results from the current study may contribute to the general view on the biophysical effects of therapeutic ultrasound on cell morphology and, particularly, the understanding of this effect in relation to the nuclear envelope.
- MeSH
- elektronová mikroskopie metody využití MeSH
- HL-60 buňky cytologie ultrasonografie MeSH
- intracelulární membrány ultrasonografie MeSH
- jaderný obal * ultrasonografie ultrastruktura MeSH
- jaderný pór ultrastruktura MeSH
- komplex proteinů jaderného póru * ultrastruktura MeSH
- kultivační techniky metody využití MeSH
- leptání mrazem metody využití MeSH
- lidé MeSH
- mikrofotografie MeSH
- struktury buněčného jádra ultrasonografie MeSH
- ultrasonografie metody škodlivé účinky využití MeSH
- ultrazvuková terapie * metody škodlivé účinky využití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
The name "eukaryote" is derived from Greek, meaning "true kernel", and describes the domain of organisms whose cells have a nucleus. The nucleus is thus the defining feature of eukaryotes and distinguishes them from prokaryotes (Archaea and Bacteria), whose cells lack nuclei. Despite this, we discuss the intriguing possibility that organisms on the path from the first eukaryotic common ancestor to the last common ancestor of all eukaryotes did not possess a nucleus at all-at least not in a form we would recognize today-and that the nucleus in fact arrived relatively late in the evolution of eukaryotes. The clues to this alternative evolutionary path lie, most of all, in recent discoveries concerning the structure of the nuclear pore complex. We discuss the evidence for such a possibility and how this impacts our views of eukaryote origins and how eukaryotes have diversified subsequent to their last common ancestor.
The organization of the nuclear periphery is crucial for many nuclear functions. Nuclear lamins form dense network at the nuclear periphery and play a substantial role in chromatin organization, transcription regulation and in organization of nuclear pore complexes (NPCs). Here, we show that TPR, the protein located preferentially within the nuclear baskets of NPCs, associates with lamin B1. The depletion of TPR affects the organization of lamin B1 but not lamin A/C within the nuclear lamina as shown by stimulated emission depletion microscopy. Finally, reduction of TPR affects the distribution of NPCs within the nuclear envelope and the effect can be reversed by simultaneous knock-down of lamin A/C or the overexpression of lamin B1. Our work suggests a novel role for the TPR at the nuclear periphery: the TPR contributes to the organization of the nuclear lamina and in cooperation with lamins guards the interphase assembly of nuclear pore complexes.
- MeSH
- HeLa buňky MeSH
- jaderná lamina metabolismus ultrastruktura MeSH
- jaderný obal metabolismus ultrastruktura MeSH
- komplex proteinů jaderného póru antagonisté a inhibitory genetika metabolismus MeSH
- lamin typ A antagonisté a inhibitory genetika metabolismus MeSH
- lamin typ B genetika metabolismus MeSH
- lidé MeSH
- malá interferující RNA genetika metabolismus MeSH
- molekulární zobrazování MeSH
- protoonkogenní proteiny antagonisté a inhibitory genetika metabolismus MeSH
- regulace genové exprese MeSH
- signální transdukce MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
ChannelsDB (http://ncbr.muni.cz/ChannelsDB) is a database providing information about the positions, geometry and physicochemical properties of channels (pores and tunnels) found within biomacromolecular structures deposited in the Protein Data Bank. Channels were deposited from two sources; from literature using manual deposition and from a software tool automatically detecting tunnels leading to the enzymatic active sites and selected cofactors, and transmembrane pores. The database stores information about geometrical features (e.g. length and radius profile along a channel) and physicochemical properties involving polarity, hydrophobicity, hydropathy, charge and mutability. The stored data are interlinked with available UniProt annotation data mapping known mutation effects to channel-lining residues. All structures with channels are displayed in a clear interactive manner, further facilitating data manipulation and interpretation. As such, ChannelsDB provides an invaluable resource for research related to deciphering the biological function of biomacromolecular channels.
- MeSH
- aminokyseliny chemie metabolismus MeSH
- cytochrom P-450 CYP2D6 chemie genetika metabolismus MeSH
- databáze proteinů * MeSH
- eukaryotické buňky cytologie enzymologie MeSH
- exprese genu MeSH
- hydrofobní a hydrofilní interakce MeSH
- iontové kanály chemie genetika metabolismus MeSH
- jaderný pór chemie genetika metabolismus MeSH
- katalytická doména MeSH
- koenzymy chemie metabolismus MeSH
- lidé MeSH
- mutace MeSH
- prokaryotické buňky cytologie enzymologie MeSH
- software * MeSH
- statická elektřina MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The nuclear periphery (NP) plays a substantial role in chromatin organization. Heterochromatin at the NP is interspersed with active chromatin surrounding nuclear pore complexes (NPCs); however, details of the peripheral chromatin organization are missing. To discern the distribution of epigenetic marks at the NP of HeLa nuclei, we used structured illumination microscopy combined with a new MATLAB software tool for automatic NP and NPC detection, measurements of fluorescent intensity and statistical analysis of measured data. Our results show that marks for both active and non-active chromatin associate differentially with NPCs. The incidence of heterochromatin marks, such as H3K27me2 and H3K9me2, was significantly lower around NPCs. In contrast, the presence of marks of active chromatin such as H3K4me2 was only decreased very slightly around the NPCs or not at all (H3K9Ac). Interestingly, the histone demethylases LSD1 (also known as KDM1A) and KDM2A were enriched within the NPCs, suggesting that there was a chromatin-modifying mechanism at the NPCs. Inhibition of transcription resulted in a larger drop in the distribution of H1, H3K9me2 and H3K23me2, which implies that transcription has a role in the organization of heterochromatin at the NP.
- MeSH
- buněčné jádro metabolismus MeSH
- chromatin chemie metabolismus MeSH
- epigeneze genetická MeSH
- fluorescenční mikroskopie MeSH
- HeLa buňky MeSH
- heterochromatin chemie MeSH
- histondemethylasy metabolismus MeSH
- histony chemie MeSH
- jaderný obal metabolismus MeSH
- jaderný pór metabolismus MeSH
- lidé MeSH
- mikroskopie metody MeSH
- software MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
53BP1 is a mediator of DNA damage response (DDR) and a tumor suppressor whose accumulation on damaged chromatin promotes DNA repair and enhances DDR signaling. Using foci formation of 53BP1 as a readout in two human cell lines, we performed an siRNA-based functional high-content microscopy screen for modulators of cellular response to ionizing radiation (IR). Here, we provide the complete results of this screen as an information resource, and validate and functionally characterize one of the identified 'hits': a nuclear pore component NUP153 as a novel factor specifically required for 53BP1 nuclear import. Using a range of cell and molecular biology approaches including live-cell imaging, we show that knockdown of NUP153 prevents 53BP1, but not several other DDR factors, from entering the nuclei in the newly forming daughter cells. This translates into decreased IR-induced 53BP1 focus formation, delayed DNA repair and impaired cell survival after IR. In addition, NUP153 depletion exacerbates DNA damage caused by replication stress. Finally, we show that the C-terminal part of NUP153 is required for effective 53BP1 nuclear import, and that 53BP1 is imported to the nucleus through the NUP153-importin-β interplay. Our data define the structure-function relationships within this emerging 53BP1-NUP153/importin-β pathway and implicate this mechanism in the maintenance of genome integrity.
- MeSH
- buněčné jádro metabolismus MeSH
- genom lidský genetika MeSH
- HeLa buňky MeSH
- imunoblotting MeSH
- imunoprecipitace MeSH
- intracelulární signální peptidy a proteiny genetika metabolismus MeSH
- komplex proteinů jaderného póru genetika metabolismus MeSH
- lidé MeSH
- nádorové buněčné linie MeSH
- RNA interference fyziologie MeSH
- vazba proteinů genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Shuttling proteins are molecules that can facilitate transport through the nuclear envelope. A very large number of proteins are involved in this process that includes nuclear pore buildup, signal, receptor and enzyme proteins. There are many examples of proteins whose biological activity depends on nucleocytoplasmic transport. Very often they are largely responsible for the proper occurrence of cell division, maturation, development and differentiation. Thanks to the well mastered methods of in vitro cell culture, it is possible to trace the levels of protein expression and their distribution in cells. Advanced molecular techniques allow for precise determination of their displacement in time. Several studies are still being carried out, using primary cultures, to identify the factors that determine the maturation, development and differentiation of cells. In understanding of the detailed mechanisms controlling cell life, the key is not the level of expression of a specific protein, but its distribution in individual cellular compartments.
- MeSH
- aktivní transport - buněčné jádro * MeSH
- buněčné jádro metabolismus MeSH
- cytoplazma metabolismus MeSH
- lidé MeSH
- primární buněčná kultura * MeSH
- proteiny metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- dopisy MeSH
