scholarly journals Nuclear Import of Arabidopsis Poly(ADP-Ribose) Polymerase 2 Is Mediated by Importin-α and a Nuclear Localization Sequence Located Between the Predicted SAP Domains

2018 ◽  
Vol 9 ◽  
Author(s):  
Chao Chen ◽  
Raffaella De Masi ◽  
Ruth Lintermann ◽  
Lennart Wirthmueller
Keyword(s):  
Nuclear Localization ◽  
Nuclear Import ◽  
Nuclear Localization Sequence ◽  
Localization Sequence ◽  
Importin Α

scholarly journals Nuclear import ofArabidopsisPOLY(ADP-RIBOSE) POLYMERASE 2 is mediated by importin-α and a nuclear localization sequence located between the predicted SAP domains

2018 ◽  
Author(s):  
Chao Chen ◽  
Ruth Lintermann ◽  
Lennart Wirthmueller
Keyword(s):  
Nuclear Localization ◽  
Nuclear Import ◽  
Dna Lesions ◽  
Site Directed Mutagenesis ◽  
Covalent Attachment ◽  
Nuclear Localization Sequence ◽  
Diffusion Limit ◽  
Nuclear Pore ◽  
Localization Sequence ◽  
Importin Α

AbstractProteins of the poly(ADP-ribose) polymerase (PARP) family modify target proteins by covalent attachment of ADP-ribose moieties onto amino acid side chains. InArabidopsis, PARP proteins contribute to repair of DNA lesions and modulate plant responses to various abiotic and biotic stressors.ArabidopsisPARP1 and PARP2 are nuclear proteins and given that their molecular weights exceed the diffusion limit of nuclear pore complexes, an active import mechanism into the nucleus is likely. Here we use confocal microscopy of fluorescent protein-taggedArabidopsisPARP2 and PARP2 deletion constructs in combination with site-directed mutagenesis to identify a nuclear localization sequence in PARP2 that is required for nuclear import. We report that in co-immunoprecipitation assays PARP2 interacts with several isoforms of the importin-α group of nuclear transport adapters and that PARP2 binding to IMPORTIN-α2 is mediated by the identified nuclear localization sequence. Our results demonstrate that PARP2 is a cargo protein of the canonical importin-α/β nuclear import pathway.

Novel properties of the protein kinase CK2-site-regulated nuclear- localization sequence of the interferon-induced nuclear factor IFI 16

2000 ◽  
Vol 353 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Lyndall J. BRIGGS ◽  
Ricky W. JOHNSTONE ◽  
Rachel M. ELLIOT ◽  
Chong-Yun XIAO ◽  
Michelle DAWSON ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Nuclear Localization ◽  
Nuclear Import ◽  
Protein Kinase Ck2 ◽  
Protein Import ◽  
Simian Virus 40 ◽  
Simian Virus ◽  
Nuclear Localization Sequence ◽  
Localization Sequence ◽  
Kinase Ck2

Members of the interferon-induced class of nuclear factors possess a putative CcN motif, comparable with that within proteins such as the simian virus 40 large tumour antigen (T-ag), which confers phosphorylation-mediated regulation of nuclear-localization sequence (NLS)-dependent nuclear import. Here we examine the functionality of the interferon-induced factor 16 (IFI 16) CcN motif, demonstrating its ability to target a heterologous protein to the nucleus, and to be phosphorylated specifically by the CcN-motif-phosphorylating protein kinase CK2 (CK2). The IFI 16 NLS, however, has novel properties, conferring ATP-dependent nuclear import completely independent of cytosolic factors, as well as binding to nuclear components. The IFI 16 NLS is not recognized with high affinity by the NLS-binding importin heterodimer, and transport mediated by it is insensitive to non-hydrolysable GTP analogues. The IFI 16 NLS thus mediates nuclear import through a pathway completely distinct from that of conventional NLSs, such as that of T-ag, but intriguingly resembling that of the NLS of the HIV-1 transactivator protein Tat. Since the IFI 16 CK2 site enhances nuclear import through facilitating binding to nuclear components, this represents a novel mechanism by which the site regulates nuclear-protein import, and constitutes a difference between the IFI 16 and Tat NLSs that may be of importance in the immune response.

The COOH-terminal nuclear localization sequence of interferon gamma regulates STAT1 alpha nuclear translocation at an intracellular site

2000 ◽  
Vol 113 (15) ◽  
pp. 2771-2781
Author(s):  
P.S. Subramaniam ◽  
J. Larkin ◽  
M.G. Mujtaba ◽  
M.R. Walter ◽  
H.M. Johnson
Keyword(s):  
Nuclear Localization ◽  
Nuclear Import ◽  
Nuclear Translocation ◽  
Biological Activities ◽  
Nuclear Localization Sequence ◽  
Receptor Complex ◽  
Ifn Gamma ◽  
High Affinity ◽  
Gamma Receptor ◽  
Localization Sequence

We have recently shown that the nuclear localization of IFN gamma is mediated by a polybasic nuclear localization sequence (NLS) in its C terminus. This NLS is required for the full expression of biological activity of IFN gamma, both extracellularly and intracellularly. We now show that this NLS plays an integral intracellular role in the nuclear translocation of the transcription factor STAT1 alpha activated by IFN gamma. Treatment of IFN gamma with antibodies to the C-terminal region (95–133) containing the NLS blocked the induction of STAT1 alpha nuclear translocation. The antibodies had no effect on nuclear translocation of STAT1 alpha in IFN gamma treated cells. A deletion mutant of human IFN gamma, IFN gamma (1–123), which is devoid of the C-terminal NLS region was found to be biologically inactive, but was still able to bind to the IFN gamma receptor complex on cells with a K(d) similar to that of the wild-type protein. Deletion of the NLS specifically abolished the ability of IFN gamma(1–123) to initiate the nuclear translocation of STAT1 alpha, which is required for the biological activities of IFN gamma following binding to the IFN gamma receptor complex. Thus, the NLS region appears to contribute minimally to extracellular high-affinity receptor-ligand binding, yet exerts a strong functional role in STAT1 alpha nuclear localization. A high-affinity site for the interaction of the C-terminal NLS domain of IFN gamma with a K(d) approx. 3 × 10(−8) M(−1) has been described by previous studies on the intracellular cytoplasmic domain of the IFN gamma receptor alpha-chain. To examine the role of the NLS at the intracellular level, we microinjected neutralizing antibodies raised against the C-terminal NLS domain of IFN gamma into the cytoplasm of cells before treatment of cells with IFN gamma. These intracellular antibodies specifically blocked the nuclear translocation of STAT1 alpha following the subsequent treatment of these cells extracellularly with IFN gamma. These data show that the NLS domain of IFN gamma interacts at an intracellular site to regulate STAT1 alpha nuclear import. A C-terminal peptide of murine IFN gamma, IFN gamma(95–133), that contains the NLS motif, induced nuclear translocation of STAT1 alpha when taken up intracellularly by a murine macrophage cell line. Deletion of the NLS motif specifically abrogated the ability of this intracellular peptide to cause STAT1 alpha nuclear translocation. In cells activated with IFN gamma, IFN gamma was found to as part of a complex that contained STAT1 alpha and the importin-alpha analog Npi-1, which mediates STAT1 alpha nuclear import. The tyrosine phosphorylation of STAT1 alpha, the formation of the complex IFN gamma/Npi-1/STAT1 alpha complex and the subsequent nuclear translocation of STAT1 alpha were all found to be dependent on the presence of the IFN gamma NLS. Thus, the NLS of IFN gamma functions intracellularly to directly regulate the activation and ultimate nuclear translocation STAT1 alpha.

scholarly journals Nuclear Import of Cdk/Cyclin Complexes: Identification of Distinct Mechanisms for Import of Cdk2/Cyclin E and Cdc2/Cyclin B1

1999 ◽  
Vol 144 (2) ◽  
pp. 213-224 ◽  
Author(s):  
Jonathan D. Moore ◽  
Jing Yang ◽  
Ray Truant ◽  
Sally Kornbluth
Keyword(s):  
Nuclear Localization ◽  
Nuclear Import ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Cyclin E ◽  
Cyclin B1 ◽  
Transport Processes ◽  
Nuclear Localization Sequence ◽  
Nuclear Targeting ◽  
Importin Α

Reversible phosphorylation of nuclear proteins is required for both DNA replication and entry into mitosis. Consequently, most cyclin-dependent kinase (Cdk)/cyclin complexes are localized to the nucleus when active. Although our understanding of nuclear transport processes has been greatly enhanced by the recent identification of nuclear targeting sequences and soluble nuclear import factors with which they interact, the mechanisms used to target Cdk/cyclin complexes to the nucleus remain obscure; this is in part because these proteins lack obvious nuclear localization sequences. To elucidate the molecular mechanisms responsible for Cdk/cyclin transport, we examined nuclear import of fluorescent Cdk2/cyclin E and Cdc2/cyclin B1 complexes in digitonin-permeabilized mammalian cells and also examined potential physical interactions between these Cdks, cyclins, and soluble import factors. We found that the nuclear import machinery recognizes these Cdk/cyclin complexes through direct interactions with the cyclin component. Surprisingly, cyclins E and B1 are imported into nuclei via distinct mechanisms. Cyclin E behaves like a classical basic nuclear localization sequence–containing protein, binding to the α adaptor subunit of the importin-α/β heterodimer. In contrast, cyclin B1 is imported via a direct interaction with a site in the NH2 terminus of importin-β that is distinct from that used to bind importin-α.

scholarly journals The cytoplasmic filaments of the nuclear pore complex are dispensable for selective nuclear protein import

2002 ◽  
Vol 158 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Tobias C. Walther ◽  
Helen S. Pickersgill ◽  
Volker C. Cordes ◽  
Martin W. Goldberg ◽  
Terry D. Allen ◽  
...  
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Import ◽  
Protein Import ◽  
Nuclear Localization Sequence ◽  
Nuclear Pore ◽  
Slight Reduction ◽  
Cytoplasmic Filaments ◽  
Localization Sequence ◽  
Importin Α

The nuclear pore complex (NPC) mediates bidirectional macromolecular traffic between the nucleus and cytoplasm in eukaryotic cells. Eight filaments project from the NPC into the cytoplasm and are proposed to function in nuclear import. We investigated the localization and function of two nucleoporins on the cytoplasmic face of the NPC, CAN/Nup214 and RanBP2/Nup358. Consistent with previous data, RanBP2 was localized at the cytoplasmic filaments. In contrast, CAN was localized near the cytoplasmic coaxial ring. Unexpectedly, extensive blocking of RanBP2 with gold-conjugated antibodies failed to inhibit nuclear import. Therefore, RanBP2-deficient NPCs were generated by in vitro nuclear assembly in RanBP2-depleted Xenopus egg extracts. NPCs were formed that lacked cytoplasmic filaments, but that retained CAN. These nuclei efficiently imported nuclear localization sequence (NLS) or M9 substrates. NPCs lacking CAN retained RanBP2 and cytoplasmic filaments, and showed a minor NLS import defect. NPCs deficient in both CAN and RanBP2 displayed no cytoplasmic filaments and had a strikingly immature cytoplasmic appearance. However, they showed only a slight reduction in NLS-mediated import, no change in M9-mediated import, and were normal in growth and DNA replication. We conclude that RanBP2 is the major nucleoporin component of the cytoplasmic filaments of the NPC, and that these filaments do not have an essential role in importin α/β– or transportin-dependent import.

scholarly journals Probing the Specificity of Binding to the Major Nuclear Localization Sequence-binding Site of Importin-α Using Oriented Peptide Library Screening

2010 ◽  
Vol 285 (26) ◽  
pp. 19935-19946 ◽  
Author(s):  
Sundy N. Y. Yang ◽  
Agnes A. S. Takeda ◽  
Marcos R. M. Fontes ◽  
Jonathan M. Harris ◽  
David A. Jans ◽  
...  
Keyword(s):  
Binding Site ◽  
Nuclear Localization ◽  
Peptide Library ◽  
Nuclear Localization Sequence ◽  
Library Screening ◽  
Localization Sequence ◽  
Importin Α ◽  
Specificity Of Binding

The SV40 T antigen nuclear localization sequence enhances nuclear import of vector DNA in embryos of a crustacean (Litopenaeus schmitti)

Gene ◽  
2004 ◽  
Vol 337 ◽  
pp. 71-77 ◽  
Author(s):  
Amilcar Arenal ◽  
Rafael Pimentel ◽  
Carmen Garcı́a ◽  
Eulogio Pimentel ◽  
Peter Aleström
Keyword(s):  
Nuclear Localization ◽  
Nuclear Import ◽  
T Antigen ◽  
Nuclear Localization Sequence ◽  
Sv40 T Antigen ◽  
Localization Sequence ◽  
Vector Dna
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