scholarly journals Novel Nuclear Export Signal-Interacting Protein, NESI, Critical for the Assembly of Hepatitis Delta Virus

2005 ◽  
Vol 79 (13) ◽  
pp. 8113-8120 ◽  
Author(s):  
Yun-Hsin Wang ◽  
Shin C. Chang ◽  
Cheng Huang ◽  
Ya-Ping Li ◽  
Chia-Huei Lee ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Hepatitis Delta Virus ◽  
Critical Role ◽  
Specific Interaction ◽  
Nuclear Export Signal ◽  
Actin Binding ◽  
Hepatitis Delta ◽  
Interacting Protein ◽  
Export Signal ◽  
Delta Virus

ABSTRACT The process of host factor-mediated nucleocytoplasmic transport is critical for diverse cellular events in eukaryotes and the life cycle of viruses. We have previously identified a chromosome region maintenance 1-independent nuclear export signal (NES) at the C terminus of the large form of hepatitis delta antigen (HDAg), designated NES(HDAg-L) that is required for the assembly of hepatitis delta virus (HDV) (C.-H. Lee et al., J. Biol. Chem. 276:8142-8148, 2001). To look for interacting proteins of the NES(HDAg-L), yeast two-hybrid screening was applied using the GAL4-binding domain fused to the NES(HDAg-L) as bait. Among the positive clones, one encodes a protein, designated NESI [NES(HDAg-L) interacting protein] that specifically interacted with the wild-type NES(HDAg-L) but not with the export/package-defective HDAg-L mutant, NES*(HDAg-L), in which Pro-205 has been replaced by Ala. Northern blot analysis revealed NESI as the gene product of a 1.9-kb endogenous mRNA transcript that is present predominantly in human liver tissue. NESI consists of 467 amino acid residues and bears a putative actin-binding site and a bipartite nuclear localization signal. Specific interaction between HDAg-L and NESI was further confirmed by coimmunoprecipitation and immunofluorescence staining. Overexpression of antisense NESI RNAs inhibited the expression of NESI and abolished HDAg-L-mediated nuclear export and assembly of HDV genomic RNA. These data indicate a critical role of NESI in the assembly of HDV through interaction with HDAg-L.

scholarly journals Clathrin-Mediated Post-Golgi Membrane Trafficking in the Morphogenesis of Hepatitis Delta Virus

2009 ◽  
Vol 83 (23) ◽  
pp. 12314-12324 ◽  
Author(s):  
Cheng Huang ◽  
Shin C. Chang ◽  
Hui-Chin Yang ◽  
Chung-Liang Chien ◽  
Ming-Fu Chang
Keyword(s):  
Membrane Trafficking ◽  
Nuclear Export ◽  
Hepatitis Delta Virus ◽  
Intracellular Transport ◽  
Nuclear Export Signal ◽  
Single Amino Acid ◽  
Dominant Negative Mutant ◽  
Hepatitis Delta ◽  
C Terminus ◽  
Delta Virus

ABSTRACT Clathrin is involved in the endocytosis and exocytosis of cellular proteins and the process of virus infection. We have previously demonstrated that large hepatitis delta antigen (HDAg-L) functions as a clathrin adaptor, but the detailed mechanisms of clathrin involvement in the morphogenesis of hepatitis delta virus (HDV) are not clear. In this study, we found that clathrin heavy chain (CHC) is a key determinant in the morphogenesis of HDV. HDAg-L with a single amino acid substitution at the clathrin box retained nuclear export activity but failed to interact with CHC and to assemble into virus-like particles. Downregulation of CHC function by a dominant-negative mutant or by short hairpin RNA reduced the efficiency of HDV assembly, but not the secretion of hepatitis B virus subviral particles. In addition, the coexistence of a cell-permeable peptide derived from the C terminus of HDAg-L significantly interfered with the intracellular transport of HDAg-L. HDAg-L, small HBsAg, and CHC were found to colocalize with the trans-Golgi network and were highly enriched on clathrin-coated vesicles. Furthermore, genotype II HDV, which assembles less efficiently than genotype I HDV does, has a putative clathrin box in its HDAg-L but interacted only weakly with CHC. The assembly efficiency of the various HDV genotypes correlates well with the CHC-binding activity of their HDAg-Ls and coincides with the severity of disease outcome. Thus, the clathrin box and the nuclear export signal at the C terminus of HDAg-L are potential new molecular targets for HDV therapy.

scholarly journals Nuclear Export Signal-Interacting Protein Forms Complexes with Lamin A/C-Nups To Mediate the CRM1-Independent Nuclear Export of Large Hepatitis Delta Antigen

2012 ◽  
Vol 87 (3) ◽  
pp. 1596-1604 ◽  
Author(s):  
Cheng Huang ◽  
Jia-Yin Jiang ◽  
Shin C. Chang ◽  
Yeou-Guang Tsay ◽  
Mei-Ru Chen ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Chromosome Region ◽  
Nuclear Export Signal ◽  
Lamin A ◽  
Hepatitis Delta ◽  
Interacting Protein ◽  
Delta Antigen ◽  
C Terminus ◽  
Hepatitis Delta Antigen ◽  
Export Signal

ABSTRACTNuclear export is an important process that not only regulates the functions of cellular factors but also facilitates the assembly of viral nucleoprotein complexes. Chromosome region maintenance 1 (CRM1) that mediates the transport of proteins bearing the classical leucine-rich nuclear export signal (NES) is the best-characterized nuclear export receptor. Recently, several CRM1-independent nuclear export pathways were also identified. The nuclear export of the large form of hepatitis delta antigen (HDAg-L), a nucleocapsid protein of hepatitis delta virus (HDV), which contains a CRM1-independent proline-rich NES, is mediated by the host NES-interacting protein (NESI). The mechanism of the NESI protein in mediating nuclear export is still unknown. In this study, NESI was characterized as a highly glycosylated membrane protein. It interacted and colocalized well in the nuclear envelope with lamin A/C and nucleoporins. Importantly, HDAg-L could be coimmunoprecipitated with lamin A/C and nucleoporins. In addition, binding of the cargo HDAg-L to the C terminus of NESI was detected for the wild-type protein but not for the nuclear export-defective HDAg-L carrying a P205A mutation [HDAg-L(P205A)]. Knockdown of lamin A/C effectively reduced the nuclear export of HDAg-L and the assembly of HDV. These data indicate that by forming complexes with lamin A/C and nucleoporins, NESI facilitates the CRM1-independent nuclear export of HDAg-L.

scholarly journals Caspase-Dependent Cleavage of c-Abl Contributes to Apoptosis

2003 ◽  
Vol 23 (8) ◽  
pp. 2790-2799 ◽  
Author(s):  
Daniela Barilà ◽  
Alessandra Rufini ◽  
Ivano Condò ◽  
Natascia Ventura ◽  
Karel Dorey ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Death Receptor ◽  
Kinase Domain ◽  
Actin Binding ◽  
Caspase Cleavage ◽  
Nonreceptor Tyrosine Kinase ◽  
Nuclear Localization Signals ◽  
Induced Apoptosis ◽  
Export Signal

ABSTRACT The nonreceptor tyrosine kinase c-Abl may contribute to the regulation of apoptosis. c-Abl activity is induced in the nucleus upon DNA damage, and its activation is required for execution of the apoptotic program. Recently, activation of nuclear c-Abl during death receptor-induced apoptosis has been reported; however, the mechanism remains largely obscure. Here we show that c-Abl is cleaved by caspases during tumor necrosis factor- and Fas receptor-induced apoptosis. Cleavage at the very C-terminal region of c-Abl occurs mainly in the cytoplasmic compartment and generates a 120-kDa fragment that lacks the nuclear export signal and the actin-binding region but retains the intact kinase domain, the three nuclear localization signals, and the DNA-binding domain. Upon caspase cleavage, the 120-kDa fragment accumulates in the nucleus. Transient-transfection experiments show that cleavage of c-Abl may affect the efficiency of Fas-induced cell death. These data reveal a novel mechanism by which caspases can recruit c-Abl to the nuclear compartment and to the mammalian apoptotic program.

A functional study of nucleocytoplasmic transport signals of the EhNCABP166 protein from Entamoeba histolytica

Parasitology ◽  
2012 ◽  
Vol 139 (13) ◽  
pp. 1697-1710 ◽  
Author(s):  
R. URIBE ◽  
J. ALMARAZ BARRERA MA DE ◽  
M. ROBLES-FLORES ◽  
G. MENDOZA HERNÁNDEZ ◽  
A. GONZÁLEZ-ROBLES ◽  
...  
Keyword(s):  
Entamoeba Histolytica ◽  
Nuclear Localization ◽  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Cytoplasmic Domain ◽  
Nucleocytoplasmic Transport ◽  
Actin Binding ◽  
Functional Study ◽  
Nuclear Localization Signals ◽  
Export Signal

SUMMARYEhNCABP166 is an Entamoeba histolytica actin-binding protein that localizes to the nucleus and cytoplasm. Bioinformatic analysis of the EhNCABP166 amino acid sequence shows the presence of 3 bipartite nuclear localization signals (NLS) and a nuclear export signal (NES). The present study aimed to investigate the functionality of these signals in 3 ways. First, we fused each potential NLS to a cytoplasmic domain of ehFLN to determine whether the localization of this domain could be altered by the presence of the NLSs. Furthermore, the localization of each domain of EhNCABP166 was determined. Similarly, we generated mutations in the first block of bipartite signals from the domains that contained these signals. Additionally, we added an NES to 2 constructs that were then evaluated. We confirmed the intranuclear localization of EhNCABP166 using transmission electron microscopy. Fusion of each NLS resulted in shuttling of the cytoplasmic domain to the nucleus. With the exception of 2 domains, all of the evaluated domains localized within the nucleus. A mutation in the first block of bipartite signals affected the localization of the domains containing an NLS. The addition of an NES shifted the localization of these domains to the cytoplasm. The results presented here establish EhNCABP166 as a protein containing functional nuclear localization signals and a nuclear export signal.

scholarly journals Characterization of the Interaction between the Interferon-Induced Protein P56 and the Int6 Protein Encoded by a Locus of Insertion of the Mouse Mammary Tumor Virus

2000 ◽  
Vol 74 (4) ◽  
pp. 1892-1899 ◽  
Author(s):  
Jinjiao Guo ◽  
Ganes C. Sen
Keyword(s):  
Nuclear Export ◽  
Nuclear Protein ◽  
Nuclear Export Signal ◽  
Structural Basis ◽  
Specific Domain ◽  
Interacting Protein ◽  
Amino Terminal ◽  
Tumor Virus ◽  
Export Signal ◽  
Two Hybrid

ABSTRACT For determining cellular functions of the interferon-inducible human cytoplasmic protein P56, we undertook a Saccharomyces cerevisiae two-hybrid screen that identified Int6 as a P56-interacting protein. That the interaction also occurs in human cells was confirmed by coimmunoprecipitation and the observed cytoplasmic displacement of nuclear Int6 upon coexpression of P56. Because Int6 has been claimed to be both a cytoplasmic and a nuclear protein, we investigated the structural basis of this discrepancy. By mutational analyses, we showed that the Int6 protein contains a bipartite nuclear localization signal and a nuclear export signal at the far end of the amino terminus. The 20 amino-terminal residues of Int6, when they were attached to a different nuclear protein, were sufficient to translocate that protein to the cytoplasm. Within this region, replacement of any of the three leucine residues with alanine destroyed the function of the export signal. The specific domain of P56 that is required for its interaction with Int6 was mapped using the yeast two-hybrid assay and a mammalian coimmunoprecipitation assay. Both assays demonstrated that the C-terminal region of P56 containing three specific tetratricopeptide motifs is required for this interaction. In contrast, removal of an internal domain of P56 enhanced the interaction, as quantified by the two-hybrid assay.

scholarly journals Cellular Nuclear Export Factors TAP and Aly Are Required for HDAg-L-mediated Assembly of Hepatitis Delta Virus

2016 ◽  
Vol 291 (50) ◽  
pp. 26226-26238 ◽  
Author(s):  
Hsiu-Chen Huang ◽  
Chung-Pei Lee ◽  
Hui-Kang Liu ◽  
Ming-Fu Chang ◽  
Yu-Heng Lai ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Hepatitis Delta Virus ◽  
Hepatitis Delta ◽  
Delta Virus

scholarly journals Specific Interaction between the Hepatitis Delta Virus RNA and Glyceraldehyde 3-Phosphate Dehydrogenase: An Enhancement on Ribozyme Catalysis

Virology ◽  
2000 ◽  
Vol 271 (1) ◽  
pp. 46-57 ◽  
Author(s):  
Shyh-Shyan Lin ◽  
Shin C. Chang ◽  
Yun-Hsin Wang ◽  
Chiao-Yin Sun ◽  
Ming-Fu Chang
Keyword(s):  
Hepatitis Delta Virus ◽  
Specific Interaction ◽  
Hepatitis Delta ◽  
Virus Rna ◽  
Delta Virus

scholarly journals A Supraphysiological Nuclear Export Signal Is Required for Parvovirus Nuclear Export

2008 ◽  
Vol 19 (6) ◽  
pp. 2544-2552 ◽  
Author(s):  
Dieuwke Engelsma ◽  
Noelia Valle ◽  
Alexander Fish ◽  
Nathalie Salomé ◽  
José M. Almendral ◽  
...  
Keyword(s):  
Infected Mouse ◽  
Nuclear Export ◽  
Critical Role ◽  
Nuclear Export Signal ◽  
Hydrophobic Residue ◽  
Minute Virus Of Mice ◽  
Mouse Fibroblasts ◽  
Endogenous Protein ◽  
Minute Virus ◽  
Export Signal

CRM1 exports proteins that carry a short leucine-rich peptide signal, the nuclear export signal (NES), from the nucleus. Regular NESs must have low affinity for CRM1 to function optimally. We previously generated artificial NESs with higher affinities for CRM1, termed supraphysiological NESs. Here we identify a supraphysiological NES in an endogenous protein, the NS2 protein of parvovirus Minute Virus of Mice (MVM). NS2 interacts with CRM1 without the requirement of RanGTP, whereas addition of RanGTP renders the complex highly stable. Mutation of a single hydrophobic residue that inactivates regular NESs lowers the affinity of the NS2 NES for CRM1 from supraphysiological to regular. Mutant MVM harboring this regular NES is compromised in viral nuclear export and productivity. In virus-infected mouse fibroblasts we observe colocalization of NS2, CRM1 and mature virions, which is dependent on the supraphysiological NS2 NES. We conclude that supraphysiological NESs exist in nature and that the supraphysiological NS2 NES has a critical role in active nuclear export of mature MVM particles before cell lysis.

Sign in / Sign up

Export Citation Format

Share Document