Characterization of an Importin α/β-recognized nuclear localization signal in β-dystroglycan

2010 ◽  
Vol 110 (3) ◽  
pp. 706-717 ◽  
Author(s):  
Bárbara Lara-Chacón ◽  
Mario Bermúdez de León ◽  
Daniel Leocadio ◽  
Pablo Gómez ◽  
Lizeth Fuentes-Mera ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Importin Α ◽  
Localization Signal

scholarly journals Characterization of the Putative Transposase mRNA of Tag1, Which Is Ubiquitously Expressed in Arabidopsis and Can Be Induced by Agrobacterium-Mediated Transformation With dTag1 DNA

Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 693-701 ◽  
Author(s):  
Dong Liu ◽  
Nigel M Crawford
Keyword(s):  
Arabidopsis Thaliana ◽  
Transposable Element ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Transcript Levels ◽  
Agrobacterium Mediated Transformation ◽  
Transgenic Lines ◽  
Localization Signal ◽  
Transposase Mrna

Abstract Tag1 is an autonomous transposable element of Arabidopsis thaliana. Tag1 expression was examined in two ecotypes of Arabidopsis (Columbia and No-0) that were transformed with CaMV 35S-Tag1-GUS DNA. These ecotypes contain no endogenous Tag1 elements. A major 2.3-kb and several minor transcripts were detected in all major organs of the plants. The major transcript encoded a putative transposase of 84.2 kD with two nuclear localization signal sequences and a region conserved among transposases of the Ac or hAT family of elements. The abundance of Tag1 transcripts varied among transgenic lines and did not correlate with somatic excision frequency or germinal reversion rates, suggesting that factors other than transcript levels control Tag1 excision activity. In untransformed plants of the Landsberg ecotype, which contain two endogenous Tag1 elements, no Tag1 transcripts were detected. Agrobacterium-mediated transformation of these Landsberg plants with a defective 1.4-kb Tag1 element resulted in the appearance of full-length Tag1 transcripts from the endogenous elements. Transformation with control DNA containing no Tag1 sequences did not activate endogenous Tag1 expression. These results indicate that Agrobacterium-mediated transformation with dTag1 can activate the expression of Tag1.

scholarly journals Characterization of a Nuclear Localization Signal of Canine Parvovirus Capsid Proteins

1997 ◽  
Vol 250 (2) ◽  
pp. 389-394 ◽  
Author(s):  
Maija Vihinen-Ranta ◽  
Laura Kakkola ◽  
Anne Kalela ◽  
Pekka Vilja ◽  
Matti Vuento
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Canine Parvovirus ◽  
Capsid Proteins ◽  
Localization Signal

scholarly journals CRM1-mediated Recycling of Snurportin 1 to the Cytoplasm

1999 ◽  
Vol 145 (2) ◽  
pp. 255-264 ◽  
Author(s):  
Efrosyni Paraskeva ◽  
Elisa Izaurralde ◽  
F. Ralf Bischoff ◽  
Jochen Huber ◽  
Ulrike Kutay ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nuclear Export ◽  
Activation Domain ◽  
Large Domain ◽  
High Affinity ◽  
Importin Α ◽  
Localization Signal ◽  
Major Mediator ◽  
Rev Protein

Importin β is a major mediator of import into the cell nucleus. Importin β binds cargo molecules either directly or via two types of adapter molecules, importin α, for import of proteins with a classical nuclear localization signal (NLS), or snurportin 1, for import of m3G-capped U snRNPs. Both adapters have an NH2-terminal importin β–binding domain for binding to, and import by, importin β, and both need to be returned to the cytoplasm after having delivered their cargoes to the nucleus. We have shown previously that CAS mediates export of importin α. Here we show that snurportin 1 is exported by CRM1, the receptor for leucine-rich nuclear export signals (NESs). However, the interaction of CRM1 with snurportin 1 differs from that with previously characterized NESs. First, CRM1 binds snurportin 1 50-fold stronger than the Rev protein and 5,000-fold stronger than the minimum Rev activation domain. Second, snurportin 1 interacts with CRM1 not through a short peptide but rather via a large domain that allows regulation of affinity. Strikingly, snurportin 1 has a low affinity for CRM1 when bound to its m3G-capped import substrate, and a high affinity when substrate-free. This mechanism appears crucial for productive import cycles as it can ensure that CRM1 only exports snurportin 1 that has already released its import substrate in the nucleus.

scholarly journals Phospholipid Scramblase 1 Contains a Nonclassical Nuclear Localization Signal with Unique Binding Site in Importin α

2004 ◽  
Vol 280 (11) ◽  
pp. 10599-10606 ◽  
Author(s):  
Min-Hsuan Chen ◽  
Iris Ben-Efraim ◽  
Gregory Mitrousis ◽  
Nancy Walker-Kopp ◽  
Peter J. Sims ◽  
...  
Keyword(s):  
Binding Site ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Phospholipid Scramblase ◽  
Importin Α ◽  
Localization Signal ◽  
Phospholipid Scramblase 1

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 Characterization of the nuclear localization signal of high risk HPV16 E2 protein

Virology ◽  
2007 ◽  
Vol 360 (1) ◽  
pp. 191-198 ◽  
Author(s):  
Kristin Klucevsek ◽  
Mary Wertz ◽  
John Lucchi ◽  
Anna Leszczynski ◽  
Junona Moroianu
Keyword(s):  
High Risk ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
E2 Protein ◽  
Localization Signal

scholarly journals Nuclear Localization Signal and Protein Context both Mediate Importin α Specificity of Nuclear Import Substrates

2006 ◽  
Vol 26 (23) ◽  
pp. 8697-8709 ◽  
Author(s):  
Beate Friedrich ◽  
Christina Quensel ◽  
Thomas Sommer ◽  
Enno Hartmann ◽  
Matthias Köhler
Keyword(s):  
Nuclear Localization ◽  
Nuclear Import ◽  
Nuclear Localization Signal ◽  
Protein Import ◽  
Binding Studies ◽  
Vitro Binding ◽  
Importin Α ◽  
Localization Signal ◽  
Experimental Approaches

ABSTRACT The “classical” nuclear protein import pathway depends on importin α and importin β. Importin α binds nuclear localization signal (NLS)-bearing proteins and functions as an adapter to access the importin β-dependent import pathway. In humans, only one importin β is known to interact with importin α, while six α importins have been described. Various experimental approaches provided evidence that several substrates are transported specifically by particular α importins. Whether the NLS is sufficient to mediate importin α specificity is unclear. To address this question, we exchanged the NLSs of two well-characterized import substrates, the seven-bladed propeller protein RCC1, preferentially transported into the nucleus by importin α3, and the less specifically imported substrate nucleoplasmin. In vitro binding studies and nuclear import assays revealed that both NLS and protein context contribute to the specificity of importin α binding and transport.

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