scholarly journals Phenotype of HIV-1 Lacking a Functional Nuclear Localization Signal in Matrix Protein ofgagand Vpr Is Comparable to Wild-Type HIV-1 in Primary Macrophages

Virology ◽  
1999 ◽  
Vol 253 (2) ◽  
pp. 170-180 ◽  
Author(s):  
Neeltje A. Kootstra ◽  
Hanneke Schuitemaker
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Matrix Protein ◽  
Wild Type ◽  
Localization Signal ◽  
Functional Nuclear Localization Signal ◽  
Hiv 1

scholarly journals SUMOylation of the Polyglutamine Repeat Protein, Ataxin-1, Is Dependent on a Functional Nuclear Localization Signal

2005 ◽  
Vol 280 (23) ◽  
pp. 21942-21948 ◽  
Author(s):  
Brigit E. Riley ◽  
Huda Y. Zoghbi ◽  
Harry T. Orr
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
High Mobility ◽  
Wild Type ◽  
Repeat Protein ◽  
Polyglutamine Repeat ◽  
Lysine Residues ◽  
Localization Signal ◽  
Functional Nuclear Localization Signal ◽  
Polyglutamine Tract

SUMO (small ubiquitin-like modifier) is a member of the ubiquitin family of proteins. SUMO targets include proteins involved in numerous roles including nuclear transport and transcriptional regulation. The previous finding that mutant ataxin-1[82Q] disrupted promyelocytic leukemia (PML) oncogenic domains prompted us to determine whether ataxin-1 disrupts another component of PML oncogenic domains, Sp100 (100-kDa Speckled protein). Similar to the PML protein, mutant ataxin-1[82Q] redistributed Sp100 to mutant ataxin-1[82Q] nuclear inclusions. Based on the ability of PML and Sp100 to be covalently modified by SUMO, we investigated the ability of ataxin-1 to be SUMOylated. SUMO-1 was found to covalently modify the polyglutamine repeat protein ataxin-1. There was a decrease in ataxin-1 SUMOylation in the presence of the expanded polyglutamine tract, ataxin-1[82Q]. The phospho-mutant, ataxin-1[82Q]-S776A, restored SUMO levels to those of wild-type ataxin-1[30Q]. SUMOylation of ataxin-1 was dependent on a functional nuclear localization signal. Ataxin-1 SUMOylation was mapped to at least five lysine residues. Lys16, Lys194 preceding the polyglutamine tract, Lys610/Lys697 in the C-terminal ataxin high mobility group domain, and Lys746 all contribute to ataxin-1 SUMOylation.

scholarly journals Oxadiazols: a New Class of Rationally Designed Anti-Human Immunodeficiency Virus Compounds Targeting the Nuclear Localization Signal of the Viral Matrix Protein

2005 ◽  
Vol 79 (20) ◽  
pp. 13028-13036 ◽  
Author(s):  
Omar Haffar ◽  
Larisa Dubrovsky ◽  
Richard Lowe ◽  
Reem Berro ◽  
Fatah Kashanchi ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Nuclear Localization ◽  
Nuclear Import ◽  
Nuclear Localization Signal ◽  
Matrix Protein ◽  
Computer Assisted ◽  
Viral Dna ◽  
Immunodeficiency Virus ◽  
Localization Signal ◽  
Hiv 1

ABSTRACT Despite recent progress in anti-human immunodeficiency virus (HIV) therapy, drug toxicity and emergence of drug-resistant isolates during long-term treatment of HIV-infected patients necessitate the search for new targets that can be used to develop novel antiviral agents. One such target is the process of nuclear translocation of the HIV preintegration complex. Previously we described a class of arylene bis(methylketone) compounds that inhibit HIV-1 nuclear import by targeting the nuclear localization signal (NLS) in the matrix protein (MA). Here we report a different class of MA NLS-targeting compounds that was selected using computer-assisted drug design. The leading compound from this group, ITI-367, showed potent anti-HIV activity in cultures of T lymphocytes and macrophages and also inhibited HIV-1 replication in ex vivo cultured lymphoid tissue. The virus carrying inactivating mutations in MA NLS was resistant to ITI-367. Analysis by real-time PCR demonstrated that the compound specifically inhibited nuclear import of viral DNA, measured by two-long terminal repeat circle formation. Evidence of the existence of this mechanism was provided by immunofluorescent microscopy, using fluorescently labeled HIV-1, which demonstrated retention of the viral DNA in the cytoplasm of drug-treated macrophages. Compounds inhibiting HIV-1 nuclear import may be attractive candidates for further development.

A nuclear localization signal within HIV-1 matrix protein that governs infection of non-dividing cells

Nature ◽  
1993 ◽  
Vol 365 (6447) ◽  
pp. 666-669 ◽  
Author(s):  
Michael I. Bukrinsky ◽  
Sheryl Haggerty ◽  
Michael P. Dempsey ◽  
Natalia Sharova ◽  
Alexei Adzhubei ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Matrix Protein ◽  
Dividing Cells ◽  
Localization Signal ◽  
Hiv 1

scholarly journals Evolutionary Selection of the Nuclear Localization Signal in the Viral Nucleoprotein Leads to Host Adaptation of the Genus Orthobornavirus

Viruses ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1291
Author(s):  
Ryo Komorizono ◽  
Yukiko Sassa ◽  
Masayuki Horie ◽  
Akiko Makino ◽  
Keizo Tomonaga
Keyword(s):  
Host Range ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Mammalian Cells ◽  
Matrix Protein ◽  
Host Adaptation ◽  
Host Cells ◽  
Viral Glycoprotein ◽  
Mammalian Cell Lines ◽  
Localization Signal

Adaptation of the viral life cycle to host cells is necessary for efficient viral infection and replication. This evolutionary process has contributed to the mechanism for determining the host range of viruses. Orthobornaviruses, members of the family Bornaviridae, are non-segmented, negative-strand RNA viruses, and several genotypes have been isolated from different vertebrate species. Previous studies revealed that some genotypes isolated from avian species can replicate in mammalian cell lines, suggesting the zoonotic potential of avian orthobornaviruses. However, the mechanism by which the host specificity of orthobornaviruses is determined has not yet been identified. In this study, we found that the infectivity of orthobornaviruses is not determined at the viral entry step, mediated by the viral glycoprotein and matrix protein. Furthermore, we demonstrated that the nuclear localization signal (NLS) sequence in the viral nucleoprotein (N) has evolved under natural selection and determines the host-specific viral polymerase activity. A chimeric mammalian orthobornavirus, which has the NLS sequence of avian orthobornavirus N, exhibited a reduced propagation efficiency in mammalian cells. Our findings indicated that nuclear transport of the viral N is a determinant of the host range of orthobornaviruses, providing insights into the evolution and host adaptation of orthobornaviruses.

Mutations of the SBDS Gene Result in Nuclear Mislocalization.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2034-2034
Author(s):  
Masafumi Yamaguchi ◽  
Kingo Fujimura ◽  
Hanae Toga-Yamaguchi ◽  
Valentina Svetic ◽  
Naoki Okamura ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Bone Marrow Failure ◽  
Pancreatic Insufficiency ◽  
Exocrine Pancreatic Insufficiency ◽  
Expression Level ◽  
Wild Type ◽  
Nuclear Localization Signals ◽  
Localization Signal ◽  
Domain I

Abstract Shwachman-Diamond syndrome (SDS) is an autosomal-recessive disorder characterized by exocrine pancreatic insufficiency and bone marrow failure. The SDS disease locus was mapped to chromosome 7q11. We have previously reported that Shwachman-Bodian- Diamond syndrome (SBDS) gene is not required for neutrophil maturation. However, SBDS knockdown cells were sensitive to apoptotic stimuli, indicating that SBDS acts to maintain survival of granulocyte precursor cells. (Exp Hematol35; 579, 2007). A wide variety of mutations in SBDS gene has been identified, and almost of all patients show truncated immature proteins, p.K62X (c.183_184TA>CT) or p.C84fsX3 (c.258+2T>C). However, it is not yet clear how these truncated proteins affect cellular processes that result in the SDS phenotype. The SBDS protein is localized to the nucleoli but does not have the canonical nuclear localization signal. In order to clarify the molecular basis of pathogenicity of mutated SBDS proteins, we explored the subcellular distribution of normal and mutant SBDS proteins in Hela and 32Dcl3 cells. Using various N-terminal and C-terminal deletion constructs, we found N-terminal region, domain I (1-87 amino acid residue) in particular, was necessary to localize to the nucleus. The disease related mutations (C31W, K33E, N34I, L71P) and the mutations which are conserved among the species in the domain I (E44K, K62E, D70N, E82K) were generated. C31W and N34I mutants failed to localize SBDS to the nuclei. The SV40 derived nuclear localization signal was fused to these mutated SBDS protein, and these proteins were clearly localized to the nuclei. In addition to the mislocalization, the protein expression level of these mutants showed a dramatic decrease compared to the wild type. We also established SBDS wild type and domain I overexpressed 32Dcl3 cell. SBDS wild type overexpressed cells could differentiate to normal neutrophils in the presence of mG-CSF, however domain I overexpressed cells did not differentiate. Almost of all cells showed apoptosis in this domain I overexpressed cells in the presence of mG-CSF, and this was very similar like SBDS RNAi knockdown cells. The localization of endogenous SBDS protein was also analyzed in this domain I overexpressed cells. The domain I was concentrated to nuclei, however endogenous SBDS protein was diffused to cytosol. Conclusions: The present findings enable us to document the nuclear localization signals in SBDS domain I, and that the shuttling protein would promote SBDS to nuclei. These results also showed that mislocalization and/or low expression level of mutated SBDS protein would cause SDS.

scholarly journals Phosphorylation adjacent to the nuclear localization signal of human dUTPase abolishes nuclear import: structural and mechanistic insights

2013 ◽  
Vol 69 (12) ◽  
pp. 2495-2505 ◽  
Author(s):  
Gergely Róna ◽  
Mary Marfori ◽  
Máté Borsos ◽  
Ildikó Scheer ◽  
Enikő Takács ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nucleocytoplasmic Transport ◽  
Wild Type ◽  
Post Translational Modification ◽  
Nuclear Localization Signals ◽  
M Phase ◽  
Importin Α ◽  
Localization Signal

Phosphorylation adjacent to nuclear localization signals (NLSs) is involved in the regulation of nucleocytoplasmic transport. The nuclear isoform of human dUTPase, an enzyme that is essential for genomic integrity, has been shown to be phosphorylated on a serine residue (Ser11) in the vicinity of its nuclear localization signal; however, the effect of this phosphorylation is not yet known. To investigate this issue, an integrated set of structural, molecular and cell biological methods were employed. It is shown that NLS-adjacent phosphorylation of dUTPase occurs during the M phase of the cell cycle. Comparison of the cellular distribution of wild-type dUTPase with those of hyperphosphorylation- and hypophosphorylation-mimicking mutants suggests that phosphorylation at Ser11 leads to the exclusion of dUTPase from the nucleus. Isothermal titration microcalorimetry and additional independent biophysical techniques show that the interaction between dUTPase and importin-α, the karyopherin molecule responsible for `classical' NLS binding, is weakened significantly in the case of the S11E hyperphosphorylation-mimicking mutant. The structures of the importin-α–wild-type and the importin-α–hyperphosphorylation-mimicking dUTPase NLS complexes provide structural insights into the molecular details of this regulation. The data indicate that the post-translational modification of dUTPase during the cell cycle may modulate the nuclear availability of this enzyme.

scholarly journals Extracellular vesicles transfer nuclear Abl-dependent and radiation-induced miR-34c into unirradiated cells to cause bystander effects

2018 ◽  
Vol 29 (18) ◽  
pp. 2228-2242 ◽  
Author(s):  
Shubhra Rastogi ◽  
Amini Hwang ◽  
Josolyn Chan ◽  
Jean Y. J. Wang
Keyword(s):  
Extracellular Vesicles ◽  
Dna Damage Response ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Oxygen Species ◽  
Wild Type ◽  
Bystander Effects ◽  
Damage Response ◽  
Localization Signal ◽  
Radiation Induced

Ionizing radiation (IR) not only activates DNA damage response (DDR) in irradiated cells but also induces bystander effects (BE) in cells not directly targeted by radiation. How DDR pathways activated in irradiated cells stimulate BE is not well understood. We show here that extracellular vesicles secreted by irradiated cells (EV-IR), but not those from unirradiated controls (EV-C), inhibit colony formation in unirradiated cells by inducing reactive oxygen species (ROS). We found that µEV-IR from Abl nuclear localization signal–mutated ( Abl-µNLS) cells could not induce ROS, but expression of wild-type Abl restored that activity. Because nuclear Abl stimulates miR-34c biogenesis, we measured miR-34c in EV and found that its levels correlated with the ROS-inducing activity of EV. We then showed that EV from miR-34c minigene–transfected, but unirradiated cells induced ROS; and transfection with miR-34c-mimic, without radiation or EV addition, also induced ROS. Furthermore, EV-IR from miR34-family triple-knockout cells could not induce ROS, whereas EV-IR from wild-type cells could cause miR-34c increase and ROS induction in the miR-34 triple-knockout cells. These results establish a novel role for extracellular vesicles in transferring nuclear Abl-dependent and radiation-induced miR-34c into unirradiated cells to cause bystander oxidative stress.

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