Function and assembly of nuclear pore complex proteins

Bodoor, Khaldon; Shaikh, Sarah; Enarson, Paul; Chowdhury, Sharmin; Salina, Davide; Raharjo, Wahyu Hendrati; Burke, Brian

doi:10.1139/o99-038

Cited by 26 publications

(11 citation statements)

References 75 publications

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“…However, they also differ: a substantial fraction of ELYS has a strong intranuclear presence. It has been shown that certain Nups, such as Nup98, Rae 1, and Nup50, shuttle into the nucleus and reside there part time (13,(20)(21)(22)(23)(24). ELYS may resemble these Nups.…”

Section: Discussionmentioning

confidence: 99%

“…Nup62, a component of the nuclear pore central channel domain, is recruited relatively late in the nuclear envelope reassembly process, i.e., during telophase (19,20), whereas the Nup107-160 complex is recruited early (5). Immunofluorescence on HeLa cells revealed that ELYS begins to associate with the chromatin͞ nuclear periphery in late anaphase, well before Nup62 (Fig.…”

Section: Elys Is Recruited Early In the Nuclear Envelope Reassembly Pmentioning

confidence: 97%

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ELYS is a dual nucleoporin/kinetochore protein required for nuclear pore assembly and proper cell division

Rasala

Orjalo

Shen

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

252

313

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Nuclear pores span the nuclear envelope and act as gated aqueous channels to regulate the transport of macromolecules between the nucleus and cytoplasm, from individual proteins and RNAs to entire viral genomes. By far the largest subunit of the nuclear pore is the Nup107-160 complex, which consists of nine proteins and is critical for nuclear pore assembly. At mitosis, the Nup107-160 complex localizes to kinetochores, suggesting that it may also function in chromosome segregation. To investigate the dual roles of the Nup107-160 complex at the pore and during mitosis, we set out to identify binding partners by immunoprecipitation from both interphase and mitotic Xenopus egg extracts and mass spectrometry. ELYS, a putative transcription factor, was discovered to copurify with the Nup107-160 complex in Xenopus interphase extracts, Xenopus mitotic extracts, and human cell extracts. Indeed, a large fraction of ELYS localizes to the nuclear pore complexes of HeLa cells. Importantly, depletion of ELYS by RNAi leads to severe disruption of nuclear pores in the nuclear envelope, whereas lamin, Ran, and tubulin staining appear normal. At mitosis, ELYS targets to kinetochores, and RNAi depletion from HeLa cells leads to an increase in cytokinesis defects. Thus, we have identified an unexpected member of the nuclear pore and kinetochore that functions in both pore assembly at the nucleus and faithful cell division.Nup107-160 complex ͉ MEL-28 ͉ Nup133 ͉ mitosis E ssential for cell survival, nuclear pore complexes are large multiprotein assemblages, Ϸ30 times the size of the ribosome. Structurally, nuclear pores are comprised of three major domains inserted in the nuclear membranes. These domains include a massive central scaffold, cytoplasmic filaments, and a nuclear basket (1). Nuclear pores consist of multiple copies of Ϸ30 different proteins termed nucleoporins (Nups) (2). A third of these contain phenylalanine-glycine (FG) repeat domains, believed to be key sites for interaction with transport receptors (3).During vertebrate mitosis, the nuclear pore disassembles into approximately a dozen subunits, concurrent with the breakdown of the nuclear envelope. Most diffuse throughout the mitotic cytoplasm, playing no role in mitotic progression identified to date. However, a small number of nuclear pore proteins, including the Nup107-160 complex, localize to regions of the mitotic kinetochore and͞or spindle, pointing toward a function in mitotic chromosome segregation (4-15). We now know that, in vitro, the Nup107-160 complex is required for spindle assembly (15).Nuclear reassembly, which begins in late anaphase and continues through telophase, occurs at the chromatin periphery. During this time, the nuclear pore subunits reassemble, stepwise, into pore complexes within the double nuclear membrane. The Nup107-160 complex, by far the largest of the pore subunits, has been shown to play a critical role in nuclear pore assembly. The Nup107-160 complex consists to date of nine proteins (Fig. 1C: Nup160, Nup133, Nup107, Nup96, Nup8...

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Section: Discussionmentioning

confidence: 99%

Section: Elys Is Recruited Early In the Nuclear Envelope Reassembly Pmentioning

confidence: 97%

ELYS is a dual nucleoporin/kinetochore protein required for nuclear pore assembly and proper cell division

Rasala

Orjalo

Shen

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

252

313

View full text Add to dashboard Cite

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“…6C). Furthermore, the diffuse pattern exclusive of the region for the chromosome represented co-localization with nucleoporin p62, a component of the nuclear pore complex (31) (Fig. 6D).…”

Section: Coiled-coil Formation Within the Central Stalk Domain Of Krmmentioning

confidence: 98%

Identification of a Novel Kinesin-related Protein, KRMP1, as a Target for Mitotic Peptidyl-prolyl Isomerase Pin1

Kamimoto¹,

Zama²,

Aoki³

et al. 2001

Journal of Biological Chemistry

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Mitosis utilizes a number of kinesin-related proteins (KRPs). Here we report the identification of a novel KRP termed KRMP1, which has a deduced 1780-amino acid sequence composed of ternary domains. The amino-terminal head domain is most similar to the kinesin motor domain of the MKLP-1 subfamily and has an intrinsic ATPase activity that is diminished by substituting the consensus Lys-168 with Arg. The central stalk domain is predicted to form a long ␣-helical coiled-coil, and can interact with each other in vivo. An in vivo labeling experiment revealed that KRMP1 is phosphorylated, and we also found that the region within the tail domain containing Thr-1604 as the cdc2 kinase phosphorylation site differs from the bimC box conserved in the bimC subfamily of KRPs. Immunofluorescence analysis showed that endogenous KRMP1 was localized predominantly to the cytoplasm during interphase and dispersed throughout the cell during mitosis. Consistent with this finding, overexpressed KRMP1 was detected in a complicated nuclear or cytoplasmic pattern reflecting multiple nuclear localization/export signals. Furthermore, KRMP1 interacted with the mitotic peptidylprolyl isomerase Pin1 in vivo, and an in vitro interaction was detected between the tail domain of KRMP1 and the WW domain of Pin1. Overexpression of KRMP1 caused COS-7 cells to arrest at G 2 -M, and co-expression of Pin1 reversed this effect, indicating their physiological interaction. Together, our results suggest that KRMP1 is a mitotic target regulated by Pin1 and vice versa.Eukaryotic cells have a set of nucleotide-dependent molecular motors to fulfill specific demands on their viability. Cell division is the most essential and evolved system that engages a number of dynein and kinesin-related proteins (KRPs) 1 to move mitotic spindles and chromosomes in a precise and regulated order. Most of the KRPs identified thus far have been shown to be involved in the mitotic process (reviewed in Refs.

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“…Early assembly intermediates clearly have a pore membrane domain but apparently very little else and are presumably stabilized by integral pore membrane proteins such as Pom121p, which is recruited early in the reassembly process (10,11). Gp210, a pore membrane protein known to be a major constituent of the lumenal ring, is apparently recruited later in NPC assembly (11). Gp210 is also hyperphosphorylated at the early stages of mitosis, and this modification may be important to initiate the mitotic disassembly of the NPC and nuclear envelope (12).…”

Section: The Pore Membrane Domain and Formationmentioning

confidence: 99%

The Nuclear Pore Complex as a Transport Machine

Rout

Aitchison

2001

Journal of Biological Chemistry

255

191

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Nucleocytoplasmic Transport and the NuclearPore Complex Unlike their prokaryotic counterparts, eukaryotic cells separate the nuclear synthesis of DNA and RNA from cytoplasmic protein synthesis with a barrier termed the nuclear envelope (NE).1 The NE is perforated by large proteinaceous assemblies, called nuclear pore complexes (NPCs), which act as the sole gatekeepers controlling the exchange of material between the two locales (reviewed in Ref. 1). NPCs are freely permeable to small molecules (such as water and ions), but they restrict the movement of larger molecules (such as proteins and RNAs) across the NE. To overcome this barrier, macromolecules carry specific signals that allow them to access the nucleocytoplasmic transport machinery of the cell. In this way the cell ensures that only selected macromolecules can travel between the nucleus and cytoplasm (reviewed in Ref. 2).Operationally, NPCs are composed of proteins called nucleoporins (or Nups) forming the stationary phase for nucleocytoplasmic exchange, whereas the mobile phase consists of soluble transport factors and their cargoes. As nucleocytoplasmic transport is driven by a series of specific interactions between components of both phases, it is frequently difficult to determine which proteins are permanent constituents of the NPC. Nevertheless, to understand how transport occurs, we must characterize the players in both phases and understand how their interplay leads to the coordinated vectorial exchange of macromolecules across the NE. In this review we focus on recent results that shed light on how some of these proteins interact to contribute to the elaborate NPC architecture and its function as a transport machine. Architecture of the NPCNPCs from different organisms share a common fundamental architecture (3). These similarities likely provide clues as to the key features common to a functioning transport machine. The NPC is a large octagonally symmetric cylindrical structure. In yeast it estimated to be ϳ50 MDa, whereas in metazoans it is over twice this mass (3,4). Given that a ribosome at 4 MDa contains ϳ80 proteins, it might be expected that the NPC would contain hundreds of different nucleoporins. However, it has recently been shown that the yeast NPC contains only ϳ30 different proteins and the vertebrate NPC contains perhaps a few more (5). This raises the question of how such a large complex can be constructed from so few component parts. The answer appears to lie in the symmetry of the structure (Figs. 1-3). The NPC is comprised of a cylindrical core from which numerous peripheral filaments project toward the nucleus and cytoplasm (reviewed in Ref. 6) (Figs. 1 and 2). The remarkable symmetry of the NPC is most apparent in the central core. Not only is it composed of eight identical spokes, but each spoke is also seemingly mirror symmetrical both in a plane parallel to the NE and in a perpendicular plane running through the cylindrical axis. As predicted from this symmetry, all nucleoporins examined thus far are present in multiple...

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Function and assembly of nuclear pore complex proteins

Cited by 26 publications

References 75 publications

ELYS is a dual nucleoporin/kinetochore protein required for nuclear pore assembly and proper cell division

ELYS is a dual nucleoporin/kinetochore protein required for nuclear pore assembly and proper cell division

Identification of a Novel Kinesin-related Protein, KRMP1, as a Target for Mitotic Peptidyl-prolyl Isomerase Pin1

The Nuclear Pore Complex as a Transport Machine

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