scholarly journals Mechanical stress triggers nuclear remodeling and the formation of transmembrane actin nuclear lines with associated nuclear pore complexes

2020 ◽  
Vol 31 (16) ◽  
pp. 1774-1787 ◽  
Author(s):  
Laura M. Hoffman ◽  
Mark A. Smith ◽  
Christopher C. Jensen ◽  
Masaaki Yoshigi ◽  
Elizabeth Blankman ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Experimental Approach ◽  
Mechanical Response ◽  
Structure And Function ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Biological Studies ◽  
Pore Complexes ◽  
And Function ◽  
Nuclear Remodeling

Mechanical force induces multiple intracellular responses, including actin cytoskeletal and nuclear remodeling. We report a reliable experimental approach to study the effects of directional mechanical stress on cytoskeletal and nuclear structure and function, providing a foundation for cell biological studies of mechanical response.

scholarly journals Concentration-dependent lamin assembly and its roles in the localization of other nuclear proteins

2014 ◽  
Vol 25 (8) ◽  
pp. 1287-1297 ◽  
Author(s):  
Yuxuan Guo ◽  
Youngjo Kim ◽  
Takeshi Shimi ◽  
Robert D. Goldman ◽  
Yixian Zheng
Keyword(s):  
Nuclear Lamina ◽  
Nuclear Pore ◽  
Lamin A ◽  
Nuclear Pore Complexes ◽  
Developmental Defects ◽  
Protein Levels ◽  
Lamin B1 ◽  
Mouse Cells ◽  
Pore Complexes ◽  
And Function

The nuclear lamina (NL) consists of lamin polymers and proteins that bind to the polymers. Disruption of NL proteins such as lamin and emerin leads to developmental defects and human diseases. However, the expression of multiple lamins, including lamin-A/C, lamin-B1, and lamin-B2, in mammals has made it difficult to study the assembly and function of the NL. Consequently, it has been unclear whether different lamins depend on one another for proper NL assembly and which NL functions are shared by all lamins or are specific to one lamin. Using mouse cells deleted of all or different combinations of lamins, we demonstrate that the assembly of each lamin into the NL depends primarily on the lamin concentration present in the nucleus. When expressed at sufficiently high levels, each lamin alone can assemble into an evenly organized NL, which is in turn sufficient to ensure the even distribution of the nuclear pore complexes. By contrast, only lamin-A can ensure the localization of emerin within the NL. Thus, when investigating the role of the NL in development and disease, it is critical to determine the protein levels of relevant lamins and the intricate shared or specific lamin functions in the tissue of interest.

scholarly journals A role for Gle1, a regulator of DEAD-box RNA helicases, at centrosomes and basal bodies

2017 ◽  
Vol 28 (1) ◽  
pp. 120-127 ◽  
Author(s):  
Li-En Jao ◽  
Abdalla Akef ◽  
Susan R. Wente
Keyword(s):  
Mrna Export ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Rna Helicases ◽  
Microtubule Organization ◽  
Developmental Defects ◽  
Dead Box ◽  
Pericentriolar Material ◽  
Pore Complexes ◽  
And Function

Control of organellar assembly and function is critical to eukaryotic homeostasis and survival. Gle1 is a highly conserved regulator of RNA-dependent DEAD-box ATPase proteins, with critical roles in both mRNA export and translation. In addition to its well-defined interaction with nuclear pore complexes, here we find that Gle1 is enriched at the centrosome and basal body. Gle1 assembles into the toroid-shaped pericentriolar material around the mother centriole. Reduced Gle1 levels are correlated with decreased pericentrin localization at the centrosome and microtubule organization defects. Of importance, these alterations in centrosome integrity do not result from loss of mRNA export. Examination of the Kupffer’s vesicle in Gle1-depleted zebrafish revealed compromised ciliary beating and developmental defects. We propose that Gle1 assembly into the pericentriolar material positions the DEAD-box protein regulator to function in localized mRNA metabolism required for proper centrosome function.

scholarly journals Targeting and function in mRNA export of nuclear pore complex protein Nup153.

1996 ◽  
Vol 134 (5) ◽  
pp. 1141-1156 ◽  
Author(s):  
R Bastos ◽  
A Lin ◽  
M Enarson ◽  
B Burke
Keyword(s):  
Nuclear Pore Complex ◽  
Protein Import ◽  
Nucleocytoplasmic Transport ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Terminal Domain ◽  
General Decline ◽  
Complex Protein ◽  
Pore Complexes ◽  
And Function

Nup153 is a large (153 kD) O-linked glyco-protein which is a component of the basket structure located on the nucleoplasmic face of nuclear pore complexes. This protein exhibits a tripartite structure consisting of a zinc finger domain flanked by large (60-70 kD) NH2- and COOH-terminal domains. When full-length human Nup153 is expressed in BHK cells, it accumulates appropriately at the nucleoplasmic face of the nuclear envelope. Targeting information for Nup153 resides in the NH2-terminal domain since this region of the molecule can direct an ordinarily cytoplasmic protein, pyruvate kinase, to the nuclear face of the nuclear pore complex. Overexpression of Nup153 results in the dramatic accumulation of nuclear poly (A)+ RNA, suggesting an inhibition of RNA export from the nucleus. This is not due to a general decline in nucleocytoplasmic transport or to occlusion or loss of nuclear pore complexes since nuclear protein import is unaffected. While overexpression of certain Nup153 constructs was found to result in the formation of unusual intranuclear membrane arrays, this structural phenotype could not be correlated with the effects on poly (A)+ RNA distribution. The RNA trafficking defect was, however, dependent upon the Nup153 COOH-terminal domain which contains most of the XFXFG repeats. It is proposed that this region of Nup153, lying within the distal ring of the nuclear basket, represents a docking site for mRNA molecules exiting the nucleus.

scholarly journals Dunking into the Lipid Bilayer: How Direct Membrane Binding of Nucleoporins Can Contribute to Nuclear Pore Complex Structure and Assembly

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3601
Author(s):  
Mohamed Hamed ◽  
Wolfram Antonin
Keyword(s):  
Nuclear Envelope ◽  
Current Knowledge ◽  
Complex Structure ◽  
Transmembrane Proteins ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Membrane Spanning ◽  
Pore Complexes ◽  
And Function ◽  
Membrane Spanning Domains

Nuclear pore complexes (NPCs) mediate the selective and highly efficient transport between the cytoplasm and the nucleus. They are embedded in the two membrane structure of the nuclear envelope at sites where these two membranes are fused to pores. A few transmembrane proteins are an integral part of NPCs and thought to anchor these complexes in the nuclear envelope. In addition, a number of nucleoporins without membrane spanning domains interact with the pore membrane. Here we review our current knowledge of how these proteins interact with the membrane and how this interaction can contribute to NPC assembly, stability and function as well as shaping of the pore membrane.

scholarly journals The yeast integral membrane protein Apq12 potentially links membrane dynamics to assembly of nuclear pore complexes

2007 ◽  
Vol 178 (5) ◽  
pp. 799-812 ◽  
Author(s):  
John J. Scarcelli ◽  
Christine A. Hodge ◽  
Charles N. Cole
Keyword(s):  
Membrane Protein ◽  
Integral Membrane Protein ◽  
Membrane Dynamics ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Cold Sensitive ◽  
Low Levels ◽  
Lower Temperature ◽  
Pore Complexes ◽  
And Function

Although the structure and function of components of the nuclear pore complex (NPC) have been the focus of many studies, relatively little is known about NPC biogenesis. In this study, we report that Apq12 is required for efficient NPC biogenesis in Saccharomyces cerevisiae. Apq12 is an integral membrane protein of the nuclear envelope (NE) and endoplasmic reticulum. Cells lacking Apq12 are cold sensitive for growth, and a subset of their nucleoporins (Nups), those that are primarily components of the cytoplasmic fibrils of the NPC, mislocalize to the cytoplasm. APQ12 deletion also causes defects in NE morphology. In the absence of Apq12, most NPCs appear to be associated with the inner but not the outer nuclear membrane. Low levels of benzyl alcohol, which increases membrane fluidity, prevented Nup mislocalization and restored the proper localization of Nups that had accumulated in cytoplasmic foci upon a shift to lower temperature. Thus, Apq12p connects nuclear pore biogenesis to the dynamics of the NE.

scholarly journals Nup358 integrates nuclear envelope breakdown with kinetochore assembly

2003 ◽  
Vol 162 (6) ◽  
pp. 991-1001 ◽  
Author(s):  
Davide Salina ◽  
Paul Enarson ◽  
J.B. Rattner ◽  
Brian Burke
Keyword(s):  
Nuclear Envelope ◽  
Mitotic Checkpoint ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Nuclear Envelope Breakdown ◽  
Chromosome Congression ◽  
Chromatid Segregation ◽  
Pore Complexes ◽  
Membrane Components ◽  
And Function

Nuclear envelope breakdown (NEBD) and release of condensed chromosomes into the cytoplasm are key events in the early stages of mitosis in metazoans. NEBD involves the disassembly of all major structural elements of the nuclear envelope, including nuclear pore complexes (NPCs), and the dispersal of nuclear membrane components. The breakdown process is facilitated by microtubules of the mitotic spindle. After NEBD, engagement of spindle microtubules with chromosome-associated kinetochores leads to chromatid segregation. Several NPC subunits relocate to kinetochores after NEBD. siRNA-mediated depletion of one of these proteins, Nup358, reveals that it is essential for kinetochore function. In the absence of Nup358, chromosome congression and segregation are severely perturbed. At the same time, the assembly of other kinetochore components is strongly inhibited, leading to aberrant kinetochore structure. The implication is that Nup358 plays an essential role in integrating NEBD with kinetochore maturation and function. Mitotic arrest associated with Nup358 depletion further suggests that mitotic checkpoint complexes may remain active at nonkinetochore sites.

scholarly journals Structural basis for assembly and function of the Nup82 complex in the nuclear pore scaffold

2015 ◽  
Vol 208 (3) ◽  
pp. 283-297 ◽  
Author(s):  
Monika Gaik ◽  
Dirk Flemming ◽  
Alexander von Appen ◽  
Panagiotis Kastritis ◽  
Norbert Mücke ◽  
...  
Keyword(s):  
Structural Model ◽  
Three Dimensional ◽  
Nucleocytoplasmic Transport ◽  
Structural Basis ◽  
Integrative Approach ◽  
Asymmetric Structure ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Pore Complexes ◽  
And Function

Nuclear pore complexes (NPCs) are huge assemblies formed from ∼30 different nucleoporins, typically organized in subcomplexes. One module, the conserved Nup82 complex at the cytoplasmic face of NPCs, is crucial to terminate mRNA export. To gain insight into the structure, assembly, and function of the cytoplasmic pore filaments, we reconstituted in yeast the Nup82–Nup159–Nsp1–Dyn2 complex, which was suitable for biochemical, biophysical, and electron microscopy analyses. Our integrative approach revealed that the yeast Nup82 complex forms an unusual asymmetric structure with a dimeric array of subunits. Based on all these data, we developed a three-dimensional structural model of the Nup82 complex that depicts how this module might be anchored to the NPC scaffold and concomitantly can interact with the soluble nucleocytoplasmic transport machinery.

scholarly journals Structure, dynamics and function of nuclear pore complexes

2008 ◽  
Vol 18 (10) ◽  
pp. 456-466 ◽  
Author(s):  
Maximiliano A. D’Angelo ◽  
Martin W. Hetzer
Keyword(s):  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Structure Dynamics ◽  
Dynamics And Function ◽  
Pore Complexes ◽  
And Function

scholarly journals Heat shock-induced changes in the structural stability of proteinaceous karyoskeletal elements in vitro and morphological effects in situ.

1987 ◽  
Vol 105 (3) ◽  
pp. 1087-1098 ◽  
Author(s):  
M McConnell ◽  
A M Whalen ◽  
D E Smith ◽  
P A Fisher
Keyword(s):  
Heat Shock ◽  
Structural Stability ◽  
Nuclear Matrix ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Pore Complexes ◽  
And Function

Karyoskeletal protein fractions prepared from Drosophila melanogaster embryos contain morphologically identifiable remnants of nuclear pore complexes and peripheral lamina as well as what appears to be an internal nuclear "matrix" (Fisher, P. A., M. Berrios, and G. Blobel, 1982, J. Cell Biol., 92: 674-686). Structural stability of these proteinaceous assemblies is dependent on thermal incubation in vitro (37 degrees C, 15 min) before subfractionation of nuclei. In the absence of such incubation, greater than 90% of the total karyoskeletal protein including major polypeptide components of internal "matrix," pore complexes, and the peripheral lamina, is solubilized by 1 M NaCl. In vivo heat shock induces karyoskeletal stabilization resembling that resulting from thermal incubation in vitro. Immunocytochemical studies have been used to establish the effects of heat shock on the organization and distribution of major karyoskeletal marker proteins in situ. Taken together, these results are consistent with the notion that in vivo, regulation of karyoskeletal plasticity (and perhaps form) may be a functionally significant component of the Drosophila heat shock response. They also have broad practical implications for studies pertaining to the structure and function of karyoskeletal protein (nuclear "matrix") fractions isolated from higher eukaryotic cells.

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