scholarly journals Nup153 Recruits the Nup107-160 Complex to the Inner Nuclear Membrane for Interphasic Nuclear Pore Complex Assembly

2015 ◽  
Vol 33 (6) ◽  
pp. 717-728 ◽  
Author(s):  
Benjamin Vollmer ◽  
Michael Lorenz ◽  
Daniel Moreno-Andrés ◽  
Mona Bodenhöfer ◽  
Paola De Magistris ◽  
...  
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Nuclear Pore ◽  
Complex Assembly ◽  
Inner Nuclear Membrane

The diverse roles of the Nup93/Nic96 complex proteins – structural scaffolds of the nuclear pore complex with additional cellular functions

2014 ◽  
Vol 395 (5) ◽  
pp. 515-528 ◽  
Author(s):  
Benjamin Vollmer ◽  
Wolfram Antonin
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Building Blocks ◽  
Transport Processes ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Cellular Functions ◽  
Complex Assembly ◽  
Essential Function ◽  
Pore Complexes

Abstract Nuclear pore complexes mediate the transport between the cell nucleoplasm and cytoplasm. These 125 MDa structures are among the largest assemblies found in eukaryotes, built from proteins organized in distinct subcomplexes that act as building blocks during nuclear pore complex biogenesis. In this review, we focus on one of these subcomplexes, the Nup93 complex in metazoa and its yeast counterpart, the Nic96 complex. We discuss its essential function in nuclear pore complex assembly as a linker between the nuclear membrane and the central part of the pore and its various roles in nuclear transport processes and beyond.

Function and assembly of nuclear pore complex proteins

1999 ◽  
Vol 77 (4) ◽  
pp. 321-329 ◽  
Author(s):  
Khaldon Bodoor ◽  
Sarah Shaikh ◽  
Paul Enarson ◽  
Sharmin Chowdhury ◽  
Davide Salina ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Nuclear Envelope ◽  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Current View ◽  
Nuclear Pore ◽  
Dynamic Component ◽  
Inner Nuclear Membrane ◽  
Inner Nuclear Membrane Protein ◽  
Nuclear Membrane Protein

Nuclear pore complexes (NPCs) are extremely elaborate structures that mediate the bidirectional movement of macromolecules between the nucleus and cytoplasm. The current view of NPC organization features a massive symmetrical framework that is embedded in the double membranes of the nuclear envelope. It embraces a central channel of as yet ill-defined structure but which may accommodate particles with diameters up to 26 nm provided that they bear specific import/export signals. Attached to both faces of the central framework are peripheral structures, short cytoplasmic filaments, and a nuclear basket assembly, which interact with molecules transiting the NPC. The mechanisms of assembly and the nature of NPC structural intermediates are still poorly understood. However, mutagenesis and expression studies have revealed discrete sequences within certain NPC proteins that are necessary and sufficient for their appropriate targeting. In addition, some details are emerging from observations on cells undergoing mitosis where the nuclear envelope is disassembled and its components, including NPC subunits, are dispersed throughout the mitotic cytoplasm. At the end of mitosis, all of these components are reutilized to form nuclear envelopes in the two daughter cells. To date, it has been possible to define a time course of postmitotic assembly for a group of NPC components (CAN/Nup214, Nup153, POM121, p62 and Tpr) relative to the integral inner nuclear membrane protein LAP2 and the NPC membrane glycoprotein gp210. Nup153, a dynamic component of the nuclear basket, associates with chromatin towards the end of anaphase coincident with, although independent of, the inner nuclear membrane protein, LAP2. Assembly of the remaining proteins follows that of the nuclear membranes and occurs in the sequence POM121, p62, CAN/Nup214 and gp210/Tpr. Since p62 remains as a complex with three other NPC proteins (p58, p54, p45) during mitosis, and CAN/Nup214 maintains a similar interaction with its partner, Nup84, the relative timing of assembly of these additional four proteins may also be inferred. These observations suggest that there is a sequential association of NPC proteins with chromosomes during nuclear envelope reformation and the recruitment of at least eight of these precedes that of gp210. These findings support a model in which it is POM121 rather than gp210 that defines initial membrane-associated NPC assembly intermediates and which may therefore represent an essential component of the central framework of the NPC. Key words: nuclear pore complex, nucleoporin, mitosis, nuclear transport

Reticulon-like REEP4 at the inner nuclear membrane promotes nuclear pore complex formation

2021 ◽  
Vol 221 (2) ◽  
Author(s):  
Banafsheh Golchoubian ◽  
Andreas Brunner ◽  
Helena Bragulat-Teixidor ◽  
Annett Neuner ◽  
Busra A. Akarlar ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Nucleocytoplasmic Transport ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Inner Nuclear Membrane ◽  
Pore Complexes ◽  
Late Stages ◽  
Protein Complex Assembly

Nuclear pore complexes (NPCs) are channels within the nuclear envelope that mediate nucleocytoplasmic transport. NPCs form within the closed nuclear envelope during interphase or assemble concomitantly with nuclear envelope reformation in late stages of mitosis. Both interphase and mitotic NPC biogenesis require coordination of protein complex assembly and membrane deformation. During early stages of mitotic NPC assembly, a seed for new NPCs is established on chromatin, yet the factors connecting the NPC seed to the membrane of the forming nuclear envelope are unknown. Here, we report that the reticulon homology domain protein REEP4 not only localizes to high-curvature membrane of the cytoplasmic endoplasmic reticulum but is also recruited to the inner nuclear membrane by the NPC biogenesis factor ELYS. This ELYS-recruited pool of REEP4 promotes NPC assembly and appears to be particularly important for NPC formation during mitosis. These findings suggest a role for REEP4 in coordinating nuclear envelope reformation with mitotic NPC biogenesis.

scholarly journals Inner nuclear membrane protein transport is mediated by multiple mechanisms

2008 ◽  
Vol 36 (6) ◽  
pp. 1373-1377 ◽  
Author(s):  
Nikolaj Zuleger ◽  
Nadia Korfali ◽  
Eric C. Schirmer
Keyword(s):  
Nuclear Envelope ◽  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Protein Transport ◽  
Protein Translocation ◽  
Lateral Diffusion ◽  
Membrane System ◽  
Nuclear Pore ◽  
Inner Nuclear Membrane ◽  
Classical Transport

Work in the nuclear transport field has led to an incredibly detailed description of protein translocation through the central channel of the nuclear pore complex, yet the mechanism by which nuclear envelope transmembrane proteins reach the inner nuclear membrane after synthesis in the endoplasmic reticulum is still hotly debated. Three different translocation models have gained experimental support: (i) simple lateral diffusion through the nuclear envelope membrane system; (ii) translocation by vesicle fusion events; and (iii) a variation on classical transport mediated by the nuclear pore complex. Although these models appear to be mutually exclusive, in the present paper we argue that they probably all function for different inner nuclear membrane proteins according to their unique characteristics.

scholarly journals REEP4 is recruited to the inner nuclear membrane by ELYS and promotes nuclear pore complex formation

2020 ◽  
Author(s):  
Banafsheh Golchoubian ◽  
Andreas Brunner ◽  
Helena Bragulat-Teixidor ◽  
Busra A. Akarlar ◽  
Nurhan Ozlu ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Nucleocytoplasmic Transport ◽  
Local Deformation ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Membrane Remodeling ◽  
Inner Nuclear Membrane ◽  
Pore Complexes

AbstractNuclear pore complexes (NPCs) are channels within the nuclear envelope that mediate nucleocytoplasmic transport. NPCs assemble either into the closed nuclear envelope during interphase or concomitantly with nuclear envelope reformation during anaphase. Both, interphase and post-mitotic NPC biogenesis require local deformation of membrane. Yet, the factors that control proper membrane remodeling for post-mitotic NPC assembly are unknown. Here, we report that the reticulon homology domain-protein REEP4 localizes not only to high-curvature membrane of the cytoplasmic endoplasmic reticulum (ER) but also to the inner nuclear membrane (INM). We show that REEP4 is recruited to the INM by the NPC biogenesis factor ELYS and promotes NPC assembly. REEP4 contributes mainly to anaphase NPC assembly, suggesting that REEP4 has an unexpected role in coordinating nuclear envelope reformation with post-mitotic NPC biogenesis.

scholarly journals The Nup155-mediated organisation of inner nuclear membrane proteins is independent of Nup155 anchoring to the metazoan nuclear pore complex

2012 ◽  
Vol 125 (18) ◽  
pp. 4214-4218 ◽  
Author(s):  
K. Busayavalasa ◽  
X. Chen ◽  
A.-K. O. Farrants ◽  
N. Wagner ◽  
N. Sabri
Keyword(s):  
Membrane Proteins ◽  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Nuclear Pore ◽  
Inner Nuclear Membrane

scholarly journals Localization of Pom121 to the inner nuclear membrane is required for an early step of interphase nuclear pore complex assembly

2011 ◽  
Vol 22 (7) ◽  
pp. 1058-1069 ◽  
Author(s):  
Tomoko Funakoshi ◽  
Michaela Clever ◽  
Ai Watanabe ◽  
Naoko Imamoto
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Nuclear Pore ◽  
Functional Domain ◽  
Early Step ◽  
Nuclear Localization Signals ◽  
Inner Nuclear Membrane ◽  
Lamin B Receptor ◽  
Importin Α ◽  
A Cell

The nuclear pore complex (NPC) is a large protein assembly that mediates molecular trafficking between the cytoplasm and the nucleus. NPCs assemble twice during the cell cycle in metazoans: postmitosis and during interphase. In this study, using small interfering RNA (siRNA) in conjunction with a cell fusion–based NPC assembly assay, we demonstrated that pore membrane protein (Pom)121, a vertebrate-specific integral membrane nucleoporin, is indispensable for an early step in interphase NPC assembly. Functional domain analysis of Pom121 showed that its nuclear localization signals, which bind to importin β via importin α and likely function with RanGTP, play an essential role in targeting Pom121 to the interphase NPC. Furthermore, a region of Pom121 that interacts with the inner nuclear membrane (INM) and lamin B receptor was found to be crucial for its NPC targeting. Based on these findings and on evidence that Pom121 localizes at the INM in the absence of a complete NPC structure, we propose that the nuclear migration of Pom121 and its subsequent interaction with INM proteins are required to initiate interphase NPC assembly. Our data also suggest, for the first time, the importance of the INM as a seeding site for “prepores” during interphase NPC assembly.

scholarly journals The nucleoporins Nup170p and Nup157p are essential for nuclear pore complex assembly

2009 ◽  
Vol 185 (3) ◽  
pp. 459-473 ◽  
Author(s):  
Tadashi Makio ◽  
Leslie H. Stanton ◽  
Cheng-Chao Lin ◽  
David S. Goldfarb ◽  
Karsten Weis ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Essential Role ◽  
Nuclear Transport ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Complex Assembly ◽  
Cytoplasmic Face ◽  
Pore Complexes

We have established that two homologous nucleoporins, Nup170p and Nup157p, play an essential role in the formation of nuclear pore complexes (NPCs) in Saccharomyces cerevisiae. By regulating their synthesis, we showed that the loss of these nucleoporins triggers a decrease in NPCs caused by a halt in new NPC assembly. Preexisting NPCs are ultimately lost by dilution as cells grow, causing the inhibition of nuclear transport and the loss of viability. Significantly, the loss of Nup170p/Nup157p had distinct effects on the assembly of different architectural components of the NPC. Nucleoporins (nups) positioned on the cytoplasmic face of the NPC rapidly accumulated in cytoplasmic foci. These nup complexes could be recruited into new NPCs after reinitiation of Nup170p synthesis, and may represent a physiological intermediate. Loss of Nup170p/Nup157p also caused core and nucleoplasmically positioned nups to accumulate in NPC-like structures adjacent to the inner nuclear membrane, which suggests that these nucleoporins are required for formation of the pore membrane and the incorporation of cytoplasmic nups into forming NPCs.

The Formation, Structure, Distribution and Frequency of Nuclear Pores

1971 ◽  
Vol 29 ◽  
pp. 518-519
Author(s):  
G. G. Maul
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Dynamic Structure ◽  
Nuclear Pore ◽  
Nuclear Pores ◽  
Filter Function ◽  
Etching Technique ◽  
Selective Filter ◽  
Membranous Part

The chromatin of eukaryotic cells is separated from the cytoplasm by a double membrane. One obvious structural specialization of the nuclear membrane is the presence of pores which have been implicated to facilitate the selective nucleocytoplasmic exchange of a variety of large molecules. Thus, the function of nuclear pores has mainly been regarded to be a passive one. Non-membranous diaphragms, radiating fibers, central rings, and other pore-associated structures were thought to play a role in the selective filter function of the nuclear pore complex. Evidence will be presented that suggests that the nuclear pore is a dynamic structure which is non-randomly distributed and can be formed during interphase, and that a close relationship exists between chromatin and the membranous part of the nuclear pore complex.Octagonality of the nuclear pore complex has been confirmed by a variety of techniques. Using the freeze-etching technique, it was possible to show that the membranous part of the pore complex has an eight-sided outline in human melanoma cells in vitro. Fibers which traverse the pore proper at its corners are continuous and indistinguishable from chromatin at the nucleoplasmic side, as seen in conventionally fixed and sectioned material. Chromatin can be seen in octagonal outline if serial sections are analyzed which are parallel but do not include nuclear membranes (Fig. 1). It is concluded that the shape of the pore rim is due to fibrous material traversing the pore, and may not have any functional significance. In many pores one can recognize a central ring with eight fibers radiating to the corners of the pore rim. Such a structural arrangement is also found to connect eight ribosomes at the nuclear membrane.

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