scholarly journals The Nup107-160 Nucleoporin Complex Promotes Mitotic Events via Control of the Localization State of the Chromosome Passenger Complex

2009 ◽  
Vol 20 (24) ◽  
pp. 5260-5275 ◽  
Author(s):  
Melpomeni Platani ◽  
Rachel Santarella-Mellwig ◽  
Markus Posch ◽  
Rudolf Walczak ◽  
Jason R. Swedlow ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Nuclear Pore Complex ◽  
Nuclear Pore ◽  
Aurora B ◽  
Major Function ◽  
Complex Functions ◽  
Chromosome Alignment ◽  
Spindle Midzone ◽  
Chromosome Passenger Complex

The human Nup107-160 nucleoporin complex plays a major role in formation of the nuclear pore complex and is localized to kinetochores in mitosis. Here we report that Seh1, a component of the Nup107-160 complex, functions in chromosome alignment and segregation by regulating the centromeric localization of Aurora B and other chromosome passenger complex proteins. Localization of CENP-E is not affected by Seh1 depletion and analysis by electron microscopy showed that microtubule kinetochore attachments are intact. Seh1-depleted cells show impaired Aurora B localization, which results in severe defects in biorientation and organization of the spindle midzone and midbody. Our results indicate that a major function of the Nup107 complex in mitosis is to ensure the proper localization of the CPC at the centromere.

scholarly journals Isolation of the yeast nuclear pore complex.

1993 ◽  
Vol 123 (4) ◽  
pp. 771-783 ◽  
Author(s):  
M P Rout ◽  
G Blobel
Keyword(s):  
Electron Microscopy ◽  
Image Reconstruction ◽  
Nuclear Pore Complex ◽  
Sedimentation Coefficient ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Negative Stain ◽  
Negative Stain Electron Microscopy ◽  
Pore Complexes

Nuclear pore complexes (NPCs) have been isolated from the yeast Saccharomyces. Negative stain electron microscopy of the isolated NPCs and subsequent image reconstruction revealed the octagonal symmetry and many of the ultrastructural features characteristic of vertebrate NPCs. The overall dimensions of the yeast NPC, both in its isolated form as well as in situ, are smaller than its vertebrate counterpart. However, the diameter of the central structures are similar. The isolated yeast NPC has a sedimentation coefficient of approximately 310 S and an M(r) of approximately 66 MD. It retains all but one of the eight known NPC proteins. In addition it contains as many as 80 uncharacterized proteins that are candidate NPC proteins.

scholarly journals Correlative super-resolution fluorescence and electron microscopy of the nuclear pore complex with molecular resolution

2014 ◽  
Vol 127 (20) ◽  
pp. 4351-4355 ◽  
Author(s):  
Anna Löschberger ◽  
Christian Franke ◽  
Georg Krohne ◽  
Sebastian van de Linde ◽  
Markus Sauer
Keyword(s):  
Electron Microscopy ◽  
Nuclear Pore Complex ◽  
Super Resolution ◽  
Nuclear Pore ◽  
Fluorescence And Electron Microscopy

scholarly journals The role of the integral membrane nucleoporins Ndc1p and Pom152p in nuclear pore complex assembly and function

2006 ◽  
Vol 173 (3) ◽  
pp. 361-371 ◽  
Author(s):  
Alexis S. Madrid ◽  
Joel Mancuso ◽  
W. Zacheus Cande ◽  
Karsten Weis
Keyword(s):  
Electron Microscopy ◽  
Saccharomyces Cerevisiae ◽  
Nuclear Envelope ◽  
Lipid Bilayers ◽  
Nuclear Pore Complex ◽  
Transmembrane Proteins ◽  
Nuclear Pore ◽  
Large Channel ◽  
And Function

The nuclear pore complex (NPC) is a large channel that spans the two lipid bilayers of the nuclear envelope and mediates transport events between the cytoplasm and the nucleus. Only a few NPC components are transmembrane proteins, and the role of these proteins in NPC function and assembly remains poorly understood. We investigate the function of the three integral membrane nucleoporins, which are Ndc1p, Pom152p, and Pom34p, in NPC assembly and transport in Saccharomyces cerevisiae. We find that Ndc1p is important for the correct localization of nuclear transport cargoes and of components of the NPC. However, the role of Ndc1p in NPC assembly is partially redundant with Pom152p, as cells lacking both of these proteins show enhanced NPC disruption. Electron microscopy studies reveal that the absence of Ndc1p and Pom152p results in aberrant pores that have enlarged diameters and lack proteinaceous material, leading to an increased diffusion between the cytoplasm and the nucleus.

scholarly journals A large particle associated with the perimeter of the nuclear pore complex.

1982 ◽  
Vol 93 (1) ◽  
pp. 63-75 ◽  
Author(s):  
P N Unwin ◽  
R A Milligan
Keyword(s):  
Electron Microscopy ◽  
Nuclear Pore Complex ◽  
Large Particle ◽  
Xenopus Oocytes ◽  
Three Dimensional ◽  
Central Axis ◽  
Dimensional Structure ◽  
Nuclear Pore ◽  
Three Dimensional Structure ◽  
Large Particles

The three-dimensional structure of the nuclear pore complex has been determined to a resolution of approximately 90 A by electron microscopy using nuclear envelopes from Xenopus oocytes. It is shown to be an assembly of several discrete constituents arranged with octagonal symmetry about a central axis. There are apparent twofold axes perpendicular to the octad axis which suggest that the framework of the pore complex is constructed from two equal but oppositely facing halves. The half facing the cytoplasm is in some instances decorated by large particles, similar in appearance and size to ribosomes.

scholarly journals INCENP–aurora B interactions modulate kinase activity and chromosome passenger complex localization

2009 ◽  
Vol 187 (5) ◽  
pp. 637-653 ◽  
Author(s):  
Zhenjie Xu ◽  
Hiromi Ogawa ◽  
Paola Vagnarelli ◽  
Jan H. Bergmann ◽  
Damien F. Hudson ◽  
...  
Keyword(s):  
Kinase Activity ◽  
Aurora B ◽  
Activity Levels ◽  
Checkpoint Response ◽  
C Terminus ◽  
Chromosomal Passenger ◽  
Spindle Midzone ◽  
Low Levels ◽  
Chromosome Passenger Complex

Dynamic localization of the chromosomal passenger complex (CPC) during mitosis is essential for its diverse functions. CPC targeting to centromeres involves interactions between Survivin, Borealin, and the inner centromere protein (CENP [INCENP]) N terminus. In this study, we investigate how interactions between the INCENP C terminus and aurora B set the level of kinase activity. Low levels of kinase activity, seen in INCENP-depleted cells or in cells expressing a mutant INCENP that cannot bind aurora B, are sufficient for a spindle checkpoint response when microtubules are absent but not against low dose taxol. Intermediate kinase activity levels obtained with an INCENP mutant that binds aurora B but cannot fully activate it are sufficient for a robust response against taxol, but cannot trigger CPC transfer from the chromosomes to the anaphase spindle midzone. This transfer requires significantly higher levels of aurora B activity. These experiments reveal that INCENP interactions with aurora B in vivo modulate the level of kinase activity, thus regulating CPC localization and functions during mitosis.

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