scholarly journals Calmodulin activates nuclear protein import: A link between signal transduction and nuclear transport

1996 ◽  
Vol 93 (25) ◽  
pp. 14574-14579 ◽  
Author(s):  
T. D. Sweitzer ◽  
J. A. Hanover
Keyword(s):  
Signal Transduction ◽  
Protein Import ◽  
Nuclear Protein ◽  
Nuclear Transport ◽  
Nuclear Protein Import

In vitro characterization of rice importin β1: molecular interaction with nuclear transport factors and mediation of nuclear protein import

FEBS Letters ◽  
1998 ◽  
Vol 437 (1-2) ◽  
pp. 127-130 ◽  
Author(s):  
Chang-Jie Jiang ◽  
Naoko Imamoto ◽  
Rikyu Matsuki ◽  
Yoshihiro Yoneda ◽  
Naoki Yamamoto
Keyword(s):  
Molecular Interaction ◽  
Protein Import ◽  
Nuclear Protein ◽  
Nuclear Transport ◽  
In Vitro Characterization ◽  
Nuclear Protein Import ◽  
Transport Factors

scholarly journals Nuclear transport defects and nuclear envelope alterations are associated with mutation of the Saccharomyces cerevisiae NPL4 gene.

1996 ◽  
Vol 7 (11) ◽  
pp. 1835-1855 ◽  
Author(s):  
C DeHoratius ◽  
P A Silver
Keyword(s):  
Nuclear Envelope ◽  
Nuclear Pore Complex ◽  
Protein Import ◽  
Nuclear Protein ◽  
Nuclear Transport ◽  
Nuclear Pore ◽  
Temperature Sensitive ◽  
Nonpermissive Temperature ◽  
Temperature Sensitive Mutants ◽  
Nuclear Protein Import

To identify components involved in nuclear protein import, we used a genetic selection to isolate mutants that mislocalized a nuclear-targeted protein. We identified temperature-sensitive mutants that accumulated several different nuclear proteins in the cytoplasm when shifted to the semipermissive temperature of 30 degrees C; these were termed npl (nuclear protein localization) mutants. We now present the properties of yeast strains bearing mutations in the NPL4 gene and report the cloning of the NPL4 gene and the characterization of the Np14 protein. The npl4-1 mutant was isolated by the previously described selection scheme. The second allele, npl4-2, was identified from an independently derived collection of temperature-sensitive mutants. The npl4-1 and npl4-2 strains accumulate nuclear-targeted proteins in the cytoplasm at the nonpermissive temperature consistent with a defect in nuclear protein import. Using an in vitro nuclear import assay, we show that nuclei prepared from temperature-shifted npl4 mutant cells are unable to import nuclear-targeted proteins, even in the presence of cytosol prepared from wild-type cells. In addition, npl4-2 cells accumulate poly(A)+ RNA in the nucleus at the nonpermissive temperature, consistent with a failure to export mRNA from the nucleus. The npl4-1 and npl4-2 cells also exhibit distinct, temperature-sensitive structural defects: npl4-1 cells project extra nuclear envelope into the cytoplasm, whereas npl4-2 cells from nuclear envelope herniations that appear to be filled with poly(A)+ RNA. The NPL4 gene encodes an essential M(r) 64,000 protein that is located at the nuclear periphery and localizes in a pattern similar to nuclear pore complex proteins. Taken together, these results indicate that this gene encodes a novel nuclear pore complex or nuclear pore complex-associated component required for nuclear membrane integrity and nuclear transport.

Transportin: Nuclear Transport Receptor of a Novel Nuclear Protein Import Pathway

1996 ◽  
Vol 229 (2) ◽  
pp. 261-266 ◽  
Author(s):  
Sara Nakielny ◽  
Mikiko C Siomi ◽  
Haruhiko Siomi ◽  
W.Matthew Michael ◽  
Victoria Pollard ◽  
...  
Keyword(s):  
Protein Import ◽  
Nuclear Protein ◽  
Nuclear Transport ◽  
Nuclear Protein Import ◽  
Transport Receptor

Nuclear protein import is decreased by engineered mutants of nuclear transport factor 2 (NTF2) that do not bind GDP-Ran

1997 ◽  
Vol 272 (5) ◽  
pp. 716-730 ◽  
Author(s):  
W.David Clarkson ◽  
Anita H Corbett ◽  
Bryce M Paschal ◽  
Helen M Kent ◽  
Airlie J McCoy ◽  
...  
Keyword(s):  
Protein Import ◽  
Nuclear Protein ◽  
Nuclear Transport ◽  
Transport Factor ◽  
Nuclear Protein Import

Studying nuclear protein import in yeast

Methods ◽  
2006 ◽  
Vol 39 (4) ◽  
pp. 291-308 ◽  
Author(s):  
Deena M. Leslie ◽  
Benjamin Timney ◽  
Michael P. Rout ◽  
John D. Aitchison
Keyword(s):  
Protein Import ◽  
Nuclear Protein ◽  
Nuclear Protein Import

scholarly journals Two Isoforms of Npap60 (Nup50) Differentially Regulate Nuclear Protein Import

2010 ◽  
Vol 21 (4) ◽  
pp. 630-638 ◽  
Author(s):  
Yutaka Ogawa ◽  
Yoichi Miyamoto ◽  
Munehiro Asally ◽  
Masahiro Oka ◽  
Yoshinari Yasuda ◽  
...  
Keyword(s):  
Nuclear Import ◽  
Protein Import ◽  
Nuclear Protein ◽  
Time Lapse ◽  
Binding Assays ◽  
Vitro Binding ◽  
Importin Α ◽  
Nuclear Protein Import

Npap60 (Nup50) is a nucleoporin that binds directly to importin α. In humans, there are two Npap60 isoforms: the long (Npap60L) and short (Npap60S) forms. In this study, we provide both in vitro and in vivo evidence that Npap60L and Npap60S function differently in nuclear protein import. In vitro binding assays revealed that Npap60S stabilizes the binding of importin α to classical NLS-cargo, whereas Npap60L promotes the release of NLS-cargo from importin α. In vivo time-lapse experiments showed that when the Npap60 protein level is controlled, allowing CAS to efficiently promote the dissociation of the Npap60/importin α complex, Npap60S and Npap60L suppress and accelerate the nuclear import of NLS-cargo, respectively. These results demonstrate that Npap60L and Npap60S have opposing functions and suggest that Npap60L and Npap60S levels must be carefully controlled for efficient nuclear import of classical NLS-cargo in humans. This study provides novel evidence that nucleoporin expression levels regulate nuclear import efficiency.

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