Home About us Contact
|
Home About us Contact | ||
|
|
||
Pore Complexes (pore + complex)
Kinds of Pore Complexes Selected AbstractsFusion of ALK to the Ran-binding protein 2 (RANBP2) gene in inflammatory myofibroblastic tumorGENES, CHROMOSOMES AND CANCER, Issue 1 2003Zhigui Ma Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal proliferation of transformed myofibroblasts, with a prominent inflammatory cell component, that can mimic other spindle cell processes such as nodular fasciitis, desmoid tumor, and gastrointestinal stromal tumor. Genetic analyses have recently demonstrated rearrangements of anaplastic lymphoma kinase (ALK), located at 2p23, in a subset of IMTs. Molecular characterizations have identified ALK fusions involving tropomyosin-3 and -4 (TPM-3 and -4), the clathrin heavy chain (CLTC), and the cysteinyl-tRNA synthetase (CARS) genes as fusion partners. Here we describe two IMTs with a novel ALK fusion that involves the Ran-binding protein 2 (RANBP2) gene at 2q13, which normally encodes a large (358-kDa) nucleopore protein localized at the cytoplasmic side of the nuclear pore complex. The N-terminal 867 residues of RANBP2 are fused to the cytoplasmic segment of ALK in the 1,430,amino acid RANBP2-ALK chimeric protein. Myofibroblasts that express RANBP2-ALK exhibit nuclear membrane-associated ALK staining that is unique compared to the subcellular localization observed with other ALK fusions in IMT, presumably attributable to heteroassociation of the fusion with normal RANBP2 at the nuclear pore. These findings expand the spectrum of ALK abnormalities observed in IMT and further confirm the clonal, neoplastic nature of these lesions. © 2003 Wiley-Liss, Inc. [source] Nuclear pore complex oxalate binding protein p62: Its expression on oxalate exposure to VERO cellsJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 6 2004P. Sivakamasundari Abstract Oxalate rich stones are the most common among the various stones. Oxalate binding protein plays a vital role in the transport of oxalate. Nuclear pore complex (NPC) contains a protein of molecular weight 62 kDa and it has maximum oxalate binding activity. The physiological significance of the presence of oxalate binding protein in the NPC is not well understood. In order to study its function, the expression of this protein during oxalate stress condition and the morphological changes on oxalate exposure to synchronized VERO cells have been determined. VERO cells were synchronized at different stages of cell cycle using cell cycle blockers and expression of the NPC p62 was assessed using enzyme linked immunosorbent assay (ELISA) technique with p62 antibody (MAb 414). Expression of NPC p62 was more pronounced in 1.0 mM oxalate concentration in mitotic phase than in S phase, suggesting cell cycle dependency. During oxalate exposure there is cell aggregation and complete degeneration of cell morphology occurs, which in turn lead to the expression of certain genes, including the NPC oxalate binding protein p62. Thus, oxalate induces degeneration of cells (may be due to the lipid peroxidation) and leads to the expression of NPC oxalate binding protein and the expression is of cell cycle dependent manner. © 2004 Wiley-Liss, Inc. [source] ULTRASTRUCTURE AND LSU rDNA,BASED REVISION OF PERIDINIUM GROUP PALATINUM (DINOPHYCEAE) WITH THE DESCRIPTION OF PALATINUS GEN.JOURNAL OF PHYCOLOGY, Issue 5 2009The name Peridinium palatinum Lauterborn currently designates a freshwater peridinioid with 13 epithecal and six cingular plates, and no apical pore complex. Freshwater dinoflagellate floras classify it in Peridinium group palatinum together with P. pseudolaeve M. Lefèvre. General ultrastructure, flagellar apparatus, and pusular components of P. palatinum were examined by serial section TEM and compared to P. cinctum (O. F. Müll.) Ehrenb. and Peridiniopsis borgei Lemmerm., respectively, types of Peridinium and Peridiniopsis. Partial LSU rDNA sequences from P. palatinum, P. pseudolaeve and several peridinioids, woloszynskioids, gymnodinioids, and other dinoflagellates were used for a phylogenetic analysis. General morphology and tabulation of taxa in group palatinum were characterized by SEM. Differences in plate numbers, affecting both the epitheca and the cingulum, combine with differences in plate ornamentation and a suite of internal cell features to suggest a generic-level distinction between Peridinium group palatinum and typical Peridinium. The branching pattern of the phylogenetic tree is compatible with this conclusion, although with low support from bootstrap values and posterior probabilities, as are sequence divergences estimated between species in group palatinum, and typical Peridinium and Peridiniopsis. Palatinus nov. gen. is proposed with the new combinations Palatinus apiculatus nov. comb. (type species; syn. Peridinium palatinum), P. apiculatus var. laevis nov. comb., and P. pseudolaevis nov. comb. Distinctive characters for Palatinus include a smooth or slightly granulate, but not areolate, plate surface, a large central pyrenoid penetrated by cytoplasmic channels and radiating into chloroplast lobes, and the presence of a peduncle-homologous microtubular strand. Palatinus cells exit the theca through the antapical-postcingular area. [source] 1,1-bis(3,-indolyl)-1-(p- substituted phenyl)methanes decrease mitochondrial membrane potential and induce apoptosis in endometrial and other cancer cell linesMOLECULAR CARCINOGENESIS, Issue 7 2008Jun Hong Abstract 1,1-Bis(3,-indolyl)-1-(p -substituted phenyl)methanes, containing p-t- butyl (DIM-C-pPhtBu) and phenyl (DIM-C-pPhC6H5) substituents, are peroxisome proliferator-activated receptor , (PPAR,) agonists; however, DIM-C-pPhtBu-induced growth inhibition and cell death in human HEC1A endometrial cancer cells is PPAR,-independent. DIM-C-pPhtBu decreased mitochondrial membrane potential (MMP) and promoted the release of cytochrome c and caspase activation and nuclear uptake of endonuclease G leading to apoptosis of HEC1A cells. DIM-C-pPhtBu specifically targeted the mitochondrial permeability transition pore complex (PTPC) because the DIM-C-pPhtBu-induced pro-apoptotic responses were inhibited by atractyloside (Atra), a compound that specifically interacts with the inner mitochondrial membrane adenine nucleotide transport (ANT) proteins. At the dose of Atra used in this study (300 µM), this compound alone did not alter the PTPC but inhibited the mitochondriotoxic effects of DIM-C-pPhtBu. DIM-C-pPhtBu/DIM-C-pPhC6H5 and Atra also differentially affected the ability of eosin-5-maleimide (EMA) to alkylate Cys160 in the ANT protein and Atra, but not DIM-C-pPhtBu, inhibited the exchange of ATP/ADP in isolated mitochondria suggesting that these pharmacophores act on different sites on the ANT protein. Results of this study show that the receptor-independent proapoptotic activity of DIM-C-pPhtBu and DIM-C-pPhC6H5 were related to novel mitochondriotoxic activities involving inner mitochondrial ANT proteins. © 2007 Wiley-Liss, Inc. [source] Regulation of early response genes in pancreatic acinar cells: external calcium and nuclear calcium signalling aspectsACTA PHYSIOLOGICA, Issue 1 2009N. Fedirko Abstract Nuclear calcium signalling has been an important topic of investigation for many years and some aspects have been the subject of debate. Our data from isolated nuclei suggest that the nuclear pore complexes (NPCs) are open even after depletion of the Ca2+ store in the nuclear envelope (NE). The NE contains ryanodine receptors (RyRs) and Ins(1,4,5)P3 receptors [Ins(1,4,5)P3Rs], most likely on both sides of the NE and these can be activated separately and independently: the RyRs by either NAADP or cADPR, and the Ins(1,4,5)P3Rs by Ins(1,4,5)P3. We have also investigated the possible consequences of nuclear calcium signals: the role of Ca2+ in the regulation of immediate early genes (IEG): c-fos, c-myc and c-jun in pancreatic acinar cells. Stimulation with Ca2+ -mobilizing agonists induced significant increases in levels of expression. Cholecystokinin (CCK) (10 nm) evoked a substantial rise in the expression levels, highly dependent on external Ca2+: the IEG expression level was lowest in Ca2+ -free solution, increased at the physiological level of 1 mm [Ca2+]o and was maximal at 10 mm [Ca2+]o, i.e.: 102 ± 22% and 163 ± 15% for c-fos; c-myc ,73 ± 13% and 106 ± 24%; c-jun ,49 ± 8% and 59 ± 9% at 1 and 10 mm of extracellular Ca2+ respectively. A low CCK concentration (10 pm) induced a small increase in expression. We conclude that extracellular Ca2+ together with nuclear Ca2+ signals induced by CCK play important roles in the induction of IEG expression. [source] The Drosophila nucleoporin gene nup154 is required for correct microfilament dynamics and cell death during oogenesisCYTOSKELETON, Issue 8 2007Maria Giovanna Riparbelli Abstract The Drosophila nucleoporin gene nup154 is required in both male and female germline for successful gametogenesis. Mutant flies lack differentiated sperm and lay abnormal eggs. We demonstrated that the egg phenotype was associated with specific alterations of the actin cytoskeleton at different stages of oogenesis. Actually, mutant egg chambers displayed an abnormal organization of both subcortical microfilaments and cytoplasmic actin bundles, that led to defective nurse cell dumping. TUNEL analysis also showed that the dumpless phenotype was associated with delayed apoptosis. The nup154 gene product was localized by conventional immunofluorescence microscopy to the nuclear envelope in a distinct punctuate pattern, characteristic of nuclear pore complex components. TEM analysis revealed that the protein was mainly distributed along filamentous structures that extended radially on the nuclear side of the pore, suggesting that Nup154 could be an integral component of the basket filaments associated with the nuclear pore complexes. We propose that Nup154 is necessary for correct nuclear pore complex functions and that the proper regulation of the actin cytoskeleton dynamics strongly relies upon nuclear pore integrity. Cell Motil. Cytoskeleton 2007. © 2007 Wiley-Liss, Inc. [source] Nucleocytoplasmic protein traffic and its significance to cell functionGENES TO CELLS, Issue 10 2000Yoshihiro Yoneda In eukaryotic cells, cell functions are maintained in an orderly manner through the continuous traffic of various proteins between the cell nucleus and the cytoplasm. The nuclear import and export of proteins occurs through nuclear pore complexes and typically requires specific signals: the nuclear localization signal and nuclear export signal, respectively. The transport pathways have been found to be highly divergent, but are known to be largely mediated by importin ,-like transport receptor family molecules. These receptor molecules bind to and carry their cargoes directly or via adapter molecules. A small GTPase Ran ensures the directionality of nuclear transport by regulating the interaction between the receptors and their cargoes through its GTP/GDP cycle. Moreover, it has been recently elucidated how the transport system is involved in various functions of cell physiology, such as cell cycle control. [source] Nuclear matrix proteins as biomarkers in prostate cancerJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2002Eddy S. Leman Abstract The nuclear matrix (NM) is the structural framework of the nucleus that consists of the peripheral lamins and pore complexes, an internal ribonucleic protein network, and residual nucleoli. The NM contains proteins that contribute to the preservation of nuclear shape and its organization. These protein components better known as the NM proteins have been demonstrated to be tissue specific, and are altered in many cancers, including prostate cancer. Alterations in nuclear morphology are hallmarks of cancer and are believed to be associated with changes in NM protein composition. Prostate cancer is the most frequently diagnosed cancer in American men and many investigators have identified unique NM proteins that appear to be specific for this disease. These NM protein changes are associated with the development of prostate cancer, as well as in some cases being indicative of cancer stage. Identification of these NM proteins specific for prostate cancer provides an insight to understanding the molecular changes associated with this disease. This article reviews the role of NM proteins as tumor biomarkers in prostate cancer and the potential application of these proteins as therapeutic targets in the treatment of this disease. J. Cell. Biochem. 86: 213,223, 2002. © 2002 Wiley-Liss, Inc. [source] Nuclear pore disassembly from endoplasmic reticulum membranes promotes Ca2+ signalling competencyTHE JOURNAL OF PHYSIOLOGY, Issue 12 2008Michael J. Boulware The functionality of the endoplasmic reticulum (ER) as a Ca2+ storage organelle is supported by families of Ca2+ pumps, buffers and channels that regulate Ca2+ fluxes between the ER lumen and cytosol. Although many studies have identified heterogeneities in Ca2+ fluxes throughout the ER, the question of how differential functionality of Ca2+ channels is regulated within proximal regions of the same organelle is unresolved. Here, we studied the in vivo dynamics of an ER subdomain known as annulate lamellae (AL), a cytoplasmic nucleoporin-containing organelle widely used in vitro to study the mechanics of nuclear envelope breakdown. We show that nuclear pore complexes (NPCs) within AL suppress local Ca2+ signalling activity, an inhibitory influence relieved by heterogeneous dissociation of nucleoporins to yield NPC-denuded ER domains competent at Ca2+ signalling. Consequently, we propose a novel generalized role for AL , reversible attenuation of resident protein activity , such that regulated AL (dis)assembly via a kinase/phosphatase cycle allows cells to support rapid gain/loss-of-function transitions in cellular physiology. [source] Should I stay or should I go?CELLULAR MICROBIOLOGY, Issue 8 2007Nucleocytoplasmic trafficking in plant innate immunity Summary Communication between the cytoplasm and the nucleus is a fundamental feature of eukaryotic cells. Bidirectional transport of macromolecules across the nuclear envelope is typically mediated by receptors and occurs exclusively through nuclear pore complexes (NPCs). The components and molecular mechanisms regulating nucleocytoplasmic trafficking and signalling processes are well studied in animals and yeast but are poorly understood in plants. Current work shows that components of the NPC and the nuclear import and export machinery play essential roles in plant innate immunity. Translocation of defence regulators and Resistance (R) proteins between the cytoplasm and the nucleus are recently uncovered aspects of plant defence responses against pathogens. Future studies will reveal more details on the spatial and temporal dynamics and regulation of this process. [source] | |||||||||||||