scholarly journals Structural Basis of Interaction of Bipartite Nuclear Localization Signal from Agrobacterium VirD2 with Rice Importin-α

2014 ◽  
Vol 7 (6) ◽  
pp. 1061-1064 ◽  
Author(s):  
Chiung-Wen Chang ◽  
Simon J. Williams ◽  
Rafael Miguez Couñago ◽  
Bostjan Kobe
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Structural Basis ◽  
Bipartite Nuclear Localization Signal ◽  
Importin Α ◽  
Localization Signal

scholarly journals Structural Basis of High-Affinity Nuclear Localization Signal Interactions with Importin-α

Traffic ◽  
2012 ◽  
Vol 13 (4) ◽  
pp. 532-548 ◽  
Author(s):  
Mary Marfori ◽  
Thierry G. Lonhienne ◽  
Jade K. Forwood ◽  
Bostjan Kobe
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Structural Basis ◽  
High Affinity ◽  
Importin Α ◽  
Localization Signal

scholarly journals Importin α/β and Ran-GTP Regulate XCTK2 Microtubule Binding through a Bipartite Nuclear Localization Signal

2004 ◽  
Vol 15 (1) ◽  
pp. 46-57 ◽  
Author(s):  
Stephanie C. Ems-McClung ◽  
Yixian Zheng ◽  
Claire E. Walczak
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Molecular Mechanisms ◽  
Spindle Assembly ◽  
Small Gtpase ◽  
Microtubule Binding ◽  
Bipartite Nuclear Localization Signal ◽  
Importin Α ◽  
Localization Signal ◽  
Ran Gtp

The small GTPase Ran is essential for spindle assembly. Ran is proposed to act through its nuclear import receptors importin α and/or importin β to control the sequestration of proteins necessary for spindle assembly. To date, the molecular mechanisms by which the Ran pathway functions remain unclear. Using purified proteins, we have reconstituted Ran-regulated microtubule binding of the C-terminal kinesin XCTK2, a kinesin important for spindle assembly. We show that the tail of XCTK2 binds to microtubules and that this binding is inhibited in the presence of importin α and β (α/β) and restored by addition of Ran-GTP. The bipartite nuclear localization signal (NLS) in the tail of XCTK2 is essential to this process, because mutation of the NLS abolishes importin α/β-mediated regulation of XCTK2 microtubule binding. Our data show that importin α/β directly regulates the activity of XCTK2 and that one of the molecular mechanisms of Ran-regulated spindle assembly is identical to that used in classical NLS-driven nuclear transport.

scholarly journals Staufen1 is imported into the nucleolus via a bipartite nuclear localization signal and several modulatory determinants

2005 ◽  
Vol 393 (1) ◽  
pp. 245-254 ◽  
Author(s):  
Catherine Martel ◽  
Paolo Macchi ◽  
Luc Furic ◽  
Michael A. Kiebler ◽  
Luc Desgroseillers
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Nuclear Export ◽  
Mammalian Cells ◽  
Rna Binding ◽  
Binding Activity ◽  
Nuclear Trafficking ◽  
Binding Domains ◽  
Bipartite Nuclear Localization Signal ◽  
Localization Signal

Mammalian Stau1 (Staufen1), a modular protein composed of several dsRBDs (double-stranded RNA-binding domains), is probably involved in mRNA localization. Although Stau1 is mostly described in association with the rough endoplasmic reticulum and ribosomes in the cytoplasm, recent studies suggest that it may transit through the nucleus/nucleolus. Using a sensitive yeast import assay, we show that Stau1 is actively imported into the nucleus through a newly identified bipartite nuclear localization signal. As in yeast, the bipartite nuclear localization signal is necessary for Stau1 nuclear import in mammalian cells. It is also required for Stau1 nucleolar trafficking. However, Stau1 nuclear transit seems to be regulated by mechanisms that involve cytoplasmic retention and/or facilitated nuclear export. Cytoplasmic retention is mainly achieved through the action of dsRBD3, with dsRBD2 playing a supporting role in this function. Similarly, dsRBD3, but not its RNA-binding activity, is critical for Stau1 nucleolar trafficking. The function of dsRBD3 is strengthened or stabilized by the presence of dsRBD4 but prevented by the interdomain between dsRBD2 and dsRBD3. Altogether, these results suggest that Stau1 nuclear trafficking is a highly regulated process involving several determinants. The presence of Stau1 in the nucleus/nucleolus suggests that it may be involved in ribonucleoprotein formation in the nucleus and/or in other nuclear functions not necessarily related to mRNA transport.

Hairless is translocated to the nucleus via a novel bipartite nuclear localization signal and is associated with the nuclear matrix

2001 ◽  
Vol 114 (2) ◽  
pp. 367-376
Author(s):  
K. Djabali ◽  
V.M. Aita ◽  
A.M. Christiano
Keyword(s):  
Amino Acid ◽  
Hair Follicle ◽  
Nuclear Localization ◽  
Nuclear Matrix ◽  
Nuclear Localization Signal ◽  
Amino Acid Residues ◽  
Bipartite Nuclear Localization Signal ◽  
Hairless Gene ◽  
Fractionation Analysis ◽  
Localization Signal

Hair follicle cycling is an exquisitely regulated and dynamic process consisting of phases of growth, regression and quiescence. The transitions between the phases are governed by a growing number of regulatory proteins, including transcription factors. The hairless (hr) gene encodes a putative transcription factor that is highly expressed in the skin, where it appears to be an essential regulator during the regression of the catagen hair follicle. In hairless mice, as well as humans with congenital atrichia, the absence of hr gene function initiates a premature and abnormal catagen due to a dysregulation of apoptosis and cell adhesion, and defects in the signaling required for hair follicle remodeling. Here, we report structure-function studies of the hairless gene product, in which we identify a novel bipartite nuclear localization signal (NLS) of the form KRA(X13) PKR. Deletion analysis of the mouse hr gene mapped the NLS to amino acid residues 409–427. Indirect immunofluorescence microscopy of cells transiently transfected with hairless-green fluorescent fusion proteins demonstrated that these amino acid residues are necessary and sufficient for nuclear localization. Furthermore, nuclear fractionation analysis revealed that the hr protein is associated with components of the nuclear matrix.

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