Search results for "nuclear pore complex"
showing 10 items of 20 documents
Probing Differential Binding Mechanisms of Phenylalanine-Glycine-Rich Nucleoporins by Single-Molecule FRET
2018
Abstract Phenylalanine-glycine-rich nucleoporins (FG-Nups) are intrinsically disordered proteins, constituting the selective barrier of the nuclear pore complex. They are highly dynamic under physiological conditions and studying their interaction with nuclear transport receptors (NTRs) is key to understanding the molecular mechanism of nucleocytoplasmic transport. Distinct conformational features of FG-Nups interacting with diverse NTRs can be detected by multiparameter single-molecule fluorescence energy transfer (smFRET), which is a powerful technique for studying the dynamics and interactions of biomolecules in solution. Here we provide a detailed protocol utilizing smFRET to reveal dif…
Two differential binding mechanisms of FG-nucleoporins and nuclear transport receptors
2018
Summary Phenylalanine-glycine-rich nucleoporins (FG-Nups) are intrinsically disordered proteins, constituting the selective barrier of the nuclear pore complex (NPC). Previous studies showed that nuclear transport receptors (NTRs) were found to interact with FG-Nups by forming an “archetypal-fuzzy” complex through the rapid formation and breakage of interactions with many individual FG motifs. Here, we use single-molecule studies combined with atomistic simulations to show that, in sharp contrast, FG-Nup214 undergoes a coupled reconfiguration-binding mechanism when interacting with the export receptor CRM1. Association and dissociation rate constants are more than an order of magnitude lowe…
Protoparvovirus Knocking at the Nuclear Door
2017
Protoparvoviruses target the nucleus due to their dependence on the cellular reproduction machinery during the replication and expression of their single-stranded DNA genome. In recent years, our understanding of the multistep process of the capsid nuclear import has improved, and led to the discovery of unique viral nuclear entry strategies. Preceded by endosomal transport, endosomal escape and microtubule-mediated movement to the vicinity of the nuclear envelope, the protoparvoviruses interact with the nuclear pore complexes. The capsids are transported actively across the nuclear pore complexes using nuclear import receptors. The nuclear import is sometimes accompanied by structural chan…
Analysis of translocations that involve theNUP98 gene in patients with 11p15 chromosomal rearrangements
2004
The NUP98 gene has been reported to be fused with at least 15 partner genes in leukemias with 11p15 translocations. We report the results of screening of cases with cytogenetically documented rearrangements of 11p15 and the subsequent identification of involvement of NUP98 and its partner genes. We identified 49 samples from 46 hematology patients with 11p15 (including a few with 11p14) abnormalities, and using fluorescence in situ hybridization (FISH), we found that NUP98 was disrupted in 7 cases. With the use of gene-specific FISH probes, in 6 cases, we identified the partner genes, which were PRRX1 (PMX1; in 2 cases), HOXD13, RAP1GDS1, HOXC13, and TOP1. In the 3 cases for which RNA was a…
Midregion PTHrP regulates Rip1 and caspase expression in MDA-MB231 breast cancer cells.
2007
It was previously reported that the midregion PTHrP domain (38-94)-amide restrains growth and invasion "in vitro", causes striking toxicity and accelerates death of some breast cancer cell lines, the most responsive being MDA-MB231 whose tumorigenesis was also attenuated "in vivo". In addition, we have demonstrated that midregion PTHrP is imported in the nucleoplasm of cultured MDA-MB231 cells, and that "in vitro" it can bind chromatin of metaphase spread preparations and also an isolated 20-mer oligonucleotide, thereby appearing endowed with a putative transcription factor-like DNA-binding ability. Here, we examined whether PTHrP (38-94)-amide was able to modulate the expression of genes e…
Parthenolide generates reactive oxygen species and autophagy in MDA-MB231 cells. A soluble parthenolide analogue inhibits tumour growth and metastasi…
2013
Triple-negative breast cancers (TNBCs) are clinically aggressive forms associated with a poor prognosis. We evaluated the cytotoxic effect exerted on triple-negative MDA-MB231 breast cancer cells both by parthenolide and its soluble analogue dimethylamino parthenolide (DMAPT) and explored the underlying molecular mechanism. The drugs induced a dose- and time-dependent decrement in cell viability, which was not prevented by the caspase inhibitor z-VAD-fmk. In particular in the first hours of treatment (1–3 h), parthenolide and DMAPT strongly stimulated reactive oxygen species (ROS) generation. The drugs induced production of superoxide anion by activating NADPH oxidase. ROS generation caused…
Cargo transport through the nuclear pore complex at a glance.
2021
ABSTRACT Bidirectional transport of macromolecules across the nuclear envelope is a hallmark of eukaryotic cells, in which the genetic material is compartmentalized inside the nucleus. The nuclear pore complex (NPC) is the major gateway to the nucleus and it regulates nucleocytoplasmic transport, which is key to processes including transcriptional regulation and cell cycle control. Accordingly, components of the nuclear transport machinery are often found to be dysregulated or hijacked in diseases. In this Cell Science at a Glance article and accompanying poster, we provide an overview of our current understanding of cargo transport through the NPC, from the basic transport signals and mach…
Multifunctionality of F-rich nucleoporins
2020
Nucleoporins (Nups) represent a range of proteins most known for composing the macromolecular assembly of the nuclear pore complex (NPC). Among them, the family of intrinsically disordered proteins (IDPs) phenylalanine-glycine (FG) rich Nups, form the permeability barrier and coordinate the high-speed nucleocytoplasmic transport in a selective way. Those FG-Nups have been demonstrated to participate in various biological processes besides nucleocytoplasmic transport. The high number of accessible hydrophobic motifs of FG-Nups potentially gives rise to this multifunctionality, enabling them to form unique microenvironments. In this review, we discuss the multifunctionality of disordered and …
Applications of Super Resolution Expansion Microscopy in Yeast
2021
Super-resolution microscopy includes multiple techniques in optical microscopy that enable sub-diffraction resolution fluorescence imaging of cellular structures. Expansion microscopy (EXM) is a method of physical expansion to obtain super-resolution images of a biological sample on conventional microscopy. We present images of yeast organelles, applying the combination of super-resolution and ExM techniques. When preparing pre-expanded samples, conventional methods lead to breakage of dividing yeast cells and difficulties in studying division-related proteins. Here, we describe an improved sample preparation technique that avoids such damage. ExM in combination with Airyscan and structured…
Caspase-8 prevents sustained activation of NF-kappaB in monocytes undergoing macrophagic differentiation.
2006
Abstract Caspases have demonstrated several nonapoptotic functions including a role in the differentiation of specific cell types. Here, we show that caspase-8 is the upstream enzyme in the proteolytic caspase cascade whose activation is required for the differentiation of peripheral-blood monocytes into macrophages. On macrophage colony-stimulating factor (M-CSF) exposure, caspase-8 associates with the adaptor protein Fas-associated death domain (FADD), the serine/threonine kinase receptor-interacting protein 1 (RIP1) and the long isoform of FLICE-inhibitory protein FLIP. Overexpression of FADD accelerates the differentiation process that does not involve any death receptor. Active caspase…