scholarly journals Binding Dynamics of Structural Nucleoporins Govern Nuclear Pore Complex Permeability and May Mediate Channel Gating

2003 ◽  
Vol 23 (2) ◽  
pp. 534-542 ◽  
Author(s):  
Nataliya Shulga ◽  
David S. Goldfarb
Keyword(s):  
Nuclear Pore Complex ◽  
Size Range ◽  
Channel Gating ◽  
Aliphatic Alcohols ◽  
Complex Permeability ◽  
Nuclear Pore ◽  
Wild Type ◽  
Unknown Mechanism ◽  
Reversible Dissociation ◽  
Wide Size Range

ABSTRACT The nuclear pore complex (NPC) is a permeable sieve that can dilate to facilitate the bidirectional translocation of a wide size range of receptor-cargo complexes. The binding of receptors to FG nucleoporin docking sites triggers channel gating by an unknown mechanism. Previously, we used deoxyglucose and chilling treatments to implicate Nup170p and Nup188p in the control of NPC sieving in Saccharomyces cerevisiae. Here, we report that aliphatic alcohols increase the permeability of wild-type and nup170Δ NPCs. In conjunction with increases in permeability, aliphatic alcohols, deoxyglucose, and chilling trigger the reversible dissociation of several nucleoporins from nup170Δ NPCs. These results are consistent with the hypothesis that NPC gating occurs when molecular latches composed of FG repeats and structural nucleoporins dissociate.

scholarly journals The single transmembrane segment of gp210 is sufficient for sorting to the pore membrane domain of the nuclear envelope.

1992 ◽  
Vol 119 (6) ◽  
pp. 1441-1449 ◽  
Author(s):  
R W Wozniak ◽  
G Blobel
Keyword(s):  
Nuclear Envelope ◽  
Nuclear Pore Complex ◽  
Immunofluorescence Microscopy ◽  
Nuclear Pore ◽  
Transmembrane Helices ◽  
Wild Type ◽  
Transmembrane Segment ◽  
Membrane Domain ◽  
3T3 Cells ◽  
Type Mutant

The glycoprotein gp210 is located in the "pore membrane," a specialized domain of the nuclear envelope to which the nuclear pore complex (NPC) is anchored. gp210 contains a large cisternal domain, a single transmembrane segment (TM), and a COOH-terminal, 58-amino acid residue cytoplasmic tail (CT) (Wozniak, R. W., E. Bartnik, and G. Blobel. 1989. J. Cell Biol. 108:2083-2092; Greber, U. F., A. Senior, and L. Gerace. 1990. EMBO (Eur. Mol. Biol. Organ.) J. 9:1495-1502). To locate determinants for sorting of gp210 to the pore membrane, we constructed various cDNAs coding for wild-type, mutant, and chimeric gp210, and monitored localization of the expressed protein in 3T3 cells by immunofluorescence microscopy using appropriate antibodies. The large cisternal domain of gp210 (95% of its mass) did not reveal any sorting determinants. Surprisingly, the TM of gp210 is sufficient for sorting to the pore membrane. The CT also contains a sorting determinant, but it is weaker than that of the TM. We propose specific lateral association of the transmembrane helices of two proteins to yield either a gp210 homodimer or a heterodimer of gp210 and another protein. The cytoplasmically oriented tails of these dimers may bind cooperatively to the adjacent NPCs. In addition, we demonstrate that gp210 co-localizes with cytoplasmically dispersed nucleoporins, suggesting a cytoplasmic association of these components.

scholarly journals The Torsin/ NEP1R1-CTDNEP1/ Lipin axis regulates nuclear envelope lipid metabolism for nuclear pore complex insertion

2020 ◽  
Author(s):  
Julie Jacquemyn ◽  
Joyce Foroozandeh ◽  
Katlijn Vints ◽  
Jef Swerts ◽  
Patrik Verstreken ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Nuclear Envelope ◽  
Nuclear Pore Complex ◽  
Lipid Droplets ◽  
Nuclear Pore ◽  
List Type ◽  
Unknown Mechanism ◽  
Structure Lipid ◽  
Cellular Events ◽  
Upstream Regulator

AbstractTorsin ATPases of the endoplasmic reticulum (ER) and nuclear envelope (NE) lumen inhibit Lipin-mediated phosphatidate (PA) to diacylglycerol (DAG) conversion by an unknown mechanism. This excess PA metabolism is implicated in TOR1A/TorsinA diseases, but it is unclear whether it explains why Torsin concomitantly affects nuclear structure, lipid droplets (LD), organelle and cell growth. Here a fly miniscreen identified that Torsins affect these events via the NEP1R1-CTDNEP1 phosphatase complex. Further, Torsin homo-oligomerization rather than ATPase activity was key to function. NEP1R1-CTDNEP1 activates Lipin by dephosphorylation. We show that Torsin prevents CTDNEP1 from accumulating in the NE and excludes Lipin from the nucleus. Moreover, this repression of nuclear PA metabolism is required for interphase nuclear pore biogenesis. We conclude that Torsin is an upstream regulator of the NEP1R1-CTDNEP1/ Lipin pathway. This connects the ER/NE lumen with PA metabolism, and affects numerous cellular events including it has a previously unrecognized role in nuclear pore biogenesis.HighlightsNuclear envelope PA-DAG-TAG synthesis is independently regulated by Torsin and Torip/LAP1Torsin removes CTDNEP1 from the nuclear envelope and excludes Lipin from the nucleusExcess nuclear envelope NEP1R1-CTDNEP1/ Lipin activity impairs multiple aspects of NPC biogenesisNEP1R1-CTDNEP1/ Lipin inhibition prevents cellular defects associated with TOR1A and TOR1AIP1 / LAP1 disease

scholarly journals Clathrin inhibitor Pitstop-2 disrupts the nuclear pore complex permeability barrier

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Ivan Liashkovich ◽  
Dzmitry Pasrednik ◽  
Valeria Prystopiuk ◽  
Gonzalo Rosso ◽  
Hans Oberleithner ◽  
...  
Keyword(s):  
Nuclear Pore Complex ◽  
Complex Permeability ◽  
Nuclear Pore ◽  
Permeability Barrier

scholarly journals Spindle assembly checkpoint robustness requires Tpr-mediated regulation of Mad1/Mad2 proteostasis

2013 ◽  
Vol 203 (6) ◽  
pp. 883-893 ◽  
Author(s):  
Nina Schweizer ◽  
Cristina Ferrás ◽  
David M. Kern ◽  
Elsa Logarinho ◽  
Iain M. Cheeseman ◽  
...  
Keyword(s):  
Nuclear Pore Complex ◽  
Half Life ◽  
Spindle Assembly Checkpoint ◽  
Spindle Assembly ◽  
Limiting Factor ◽  
Nuclear Pore ◽  
Independent Manner ◽  
Unknown Mechanism ◽  
Rate Limiting

Tpr is a conserved nuclear pore complex (NPC) protein implicated in the spindle assembly checkpoint (SAC) by an unknown mechanism. Here, we show that Tpr is required for normal SAC response by stabilizing Mad1 and Mad2 before mitosis. Tpr coimmunoprecipitated with Mad1 and Mad2 (hereafter designated as Tpr/Mad1/Mad2 or TM2 complex) during interphase and mitosis, and is required for Mad1–c-Mad2 recruitment to NPCs. Interestingly, Tpr was normally undetectable at kinetochores and dispensable for Mad1, but not for Mad2, kinetochore localization, which suggests that SAC robustness depends on Mad2 levels at kinetochores. Protein half-life measurements demonstrate that Tpr stabilizes Mad1 and Mad2, ensuring normal Mad1–c-Mad2 production in an mRNA- and kinetochore-independent manner. Overexpression of GFP-Mad2 restored normal SAC response and Mad2 kinetochore levels in Tpr-depleted cells. Mechanistically, we provide evidence that Tpr might spatially regulate SAC proteostasis through the SUMO-isopeptidases SENP1 and SENP2 at NPCs. Thus, Tpr is a kinetochore-independent, rate-limiting factor required to mount and sustain a robust SAC response.

scholarly journals Two Nucleoporin98 homologous genes jointly participate in the regulation of starch degradation to repress senescence in Arabidopsis

2020 ◽  
Author(s):  
Long Xiao ◽  
Shanshan Jiang ◽  
Penghui Huang ◽  
Fulu Chen ◽  
Xu Wang ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Nuclear Pore Complex ◽  
Growth And Development ◽  
Double Mutant ◽  
Growth Regulation ◽  
Sugar Metabolism ◽  
Starch Degradation ◽  
Marker Genes ◽  
Nuclear Pore ◽  
Wild Type

Abstract Background: Starch is synthesized during the day for temporary storage in leaves and then degraded during the subsequent night to support plant growth and development. Impairment of starch degradation leads to stunted growth, even senescence and death. The nuclear pore complex is involved in many cellular processes, but its relationship with starch degradation is unclear until now. We previously identified that two Nucleoporin98 (Nup98) genes (Nup98a and Nup98b) redundantly regulate flowering through CONSTANS (CO) independent pathway in Arabidopsis thaliana. The nup98a-1 nup98b-1 double mutant also shows severe senescence phenotypes. Results: We find that Nucleoporin 98 (Nup98) participates in the regulation of sugar metabolism in leaves and in turn involves in senescence regulation in Arabidopsis. We show that Nup98a and Nup98b redundantly function in the different steps of starch degradation and the nup98a-1 nup98b-1 double mutant accumulates more starch than wild type plants and has a severe early senescence phenotype compared to wild type plants. The expression of marker genes related to starch degradation is impaired in the nup98a-1 nup98b-1 double mutant, and marker genes of carbon starvation and senescence express earlier and in higher abundance in the nup98a-1 nup98b-1 double mutant than in wild type plants, suggesting that abnormality of energy metabolism is the main cause of senescence of the nup98a-1 nup98b-1 double mutant. Addition of sucrose to the growth medium rescues early senescence phenotypes of the nup98a-1 nup98b-1 mutant. Conclusions: Our results provide a line of evidence on a novel role of the nuclear pore complex in energy metabolism related to growth and development, in which Nup98 functions in starch degradation conferring growth regulation in Arabidopsis.

scholarly journals Developmental Genetics of the Essential Drosophila Nucleoporin nup154: Allelic Differences Due to an Outward-Directed Promoter in the P-Element 3′ End

Genetics ◽  
1999 ◽  
Vol 153 (2) ◽  
pp. 799-812 ◽  
Author(s):  
Amy A Kiger ◽  
Silvia Gigliotti ◽  
Margaret T Fuller
Keyword(s):  
Nuclear Pore Complex ◽  
P Element ◽  
Developmental Genetics ◽  
Nuclear Pore ◽  
Transcript Analysis ◽  
Loss Of Function ◽  
Wild Type ◽  
Developmentally Regulated ◽  
Allelic Differences ◽  
Failure To Progress

Abstract Drosophila nup154 encodes a predicted nucleoporin homologous to yeast Nup170p, Nup157p, and vertebrate Nup155, all of which are major components of the nuclear pore complex (NPC). Unlike its yeast homologs, nup154 is essential for viability. Animals with strong loss-of-function nup154 mutations caused by P-element insertion in the 5′-UTR of the gene died as larvae with small discs, brains, and testes. nup154 mRNA expression appeared developmentally regulated in tissues of wild-type embryos, larvae, and adults, suggesting that new nup154 synthesis is required when assembly of new NPCs is required, as in proliferating or growing tissues. Two additional nup154 alleles also associated with different P-element inserts in the 5′-UTR were viable but had strong loss-of-function sterile phenotypes, including failure to maintain spermatogenic stem cells and failure to progress into vitellogenic stages of oogenesis. Lethality vs. viability correlated with orientation of the P-element inserts in the different alleles. Transcript analysis by 5′-RACE suggested a mechanism for allelic differences: an outward-directed promoter internal to the P-element 3′ end able to drive sufficient expression of the nup154 transcript for viability but not for fertility.

scholarly journals Two Nucleoporin98 homologous genes jointly participate in the regulation of starch degradation to repress senescence in Arabidopsis

2020 ◽  
Author(s):  
Long Xiao ◽  
Shanshan Jiang ◽  
Penghui Huang ◽  
Fulu Chen ◽  
Xu Wang ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Nuclear Pore Complex ◽  
Growth And Development ◽  
Double Mutant ◽  
Growth Regulation ◽  
Sugar Metabolism ◽  
Starch Degradation ◽  
Marker Genes ◽  
Nuclear Pore ◽  
Wild Type

Abstract Background: Starch is synthesized during daylight for temporary storage in leaves and then degraded during the subsequent night to support plant growth and development. Impairment of starch degradation leads to stunted growth, even senescence and death. The nuclear pore complex is involved in many cellular processes, but its relationship with starch degradation has been unclear until now. We previously identified that two Nucleoporin98 genes (Nup98a and Nup98b) redundantly regulate flowering via the CONSTANS (CO)-independent pathway in Arabidopsis thaliana. The double mutant also shows severe senescence phenotypes. Results: We find that Nucleoporin 98 participates in the regulation of sugar metabolism in leaves and is also involved in senescence regulation in Arabidopsis. We show that Nup98a and Nup98b function redundantly at different stages of starch degradation. The nup98a-1 nup98b-1 double mutant accumulates more starch, showing a severe early senescence phenotype compared to wild type plants. The expression of marker genes related to starch degradation is impaired in the nup98a-1 nup98b-1 double mutant, and marker genes of carbon starvation and senescence express their products earlier and in higher abundance than in wild type plants, suggesting that abnormalities in energy metabolism are the main cause of senescence in the double mutant. Addition of sucrose to the growth medium rescues early senescence phenotypes of the nup98a-1 nup98b-1 mutant. Conclusions: Our results provide evidence for a novel role of the nuclear pore complex in energy metabolism related to growth and development, in which Nup98 functions in starch degradation to control growth regulation in Arabidopsis.

scholarly journals A nuclear export sequence promotes CRM1-dependent targeting of the nucleoporin Nup214 to the nuclear pore complex

2021 ◽  
Vol 134 (6) ◽  
Author(s):  
Mohamed Hamed ◽  
Birgit Caspar ◽  
Sarah A. Port ◽  
Ralph H. Kehlenbach
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Export ◽  
Nuclear Pore ◽  
Wild Type ◽  
Leptomycin B ◽  
Nuclear Export Sequence ◽  
Binding Partners ◽  
Dependent Protein ◽  
Nuclear Export Receptor ◽  
Cytoplasmic Side

ABSTRACT Nup214 is a major nucleoporin on the cytoplasmic side of the nuclear pore complex with roles in late steps of nuclear protein and mRNA export. It interacts with the nuclear export receptor CRM1 (also known as XPO1) via characteristic phenylalanine-glycine (FG) repeats in its C-terminal region. Here, we identify a classic nuclear export sequence (NES) in Nup214 that mediates Ran-dependent binding to CRM1. Nup214 versions with mutations in the NES, as well as wild-type Nup214 in the presence of the selective CRM1 inhibitor leptomycin B, accumulate in the nucleus of Nup214-overexpressing cells. Furthermore, physiological binding partners of Nup214, such as Nup62 and Nup88, are recruited to the nucleus together with Nup214. Nuclear export of mutant Nup214 can be rescued by artificial nuclear export sequences at the C-terminal end of Nup214, leading also to a correct localization of Nup88. Our results suggest a function of the Nup214 NES in the biogenesis of the nuclear pore complex and/or in terminal steps of CRM1-dependent protein export.

scholarly journals Two Nucleoporin 98 homologous genes jointly participate in the regulation of starch degradation to enhance growth in Arabidopsis

2020 ◽  
Author(s):  
Long Xiao ◽  
Shanshan Jiang ◽  
Penghui Huang ◽  
Fulu Chen ◽  
Xu Wang ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Nuclear Pore Complex ◽  
Growth And Development ◽  
Double Mutant ◽  
Growth Regulation ◽  
Starch Degradation ◽  
Marker Genes ◽  
Nuclear Pore ◽  
Wild Type ◽  
Senescence Phenotype

Abstract Background: Starch is synthesized during the day for temporary storage in leaves and then degraded during the subsequent night to support plant growth and development. Impairment of starch degradation leads to stunted growth, even senescence and death. The nuclear pore complex is involved in many cellular processes, but its relationship with starch degradation is unclear until now. We previously identified two Nucleoporin98 ( Nup98 ) genes ( Nup98a and Nup98b ) redundantly regulated flowering through CONSTANS ( CO ) independent pathway. in Arabidopsis thaliana. The nup98a nup98b double mutant also showed severe senescence phenotypes. Results: We found that Nucleoporin 98 ( Nup98 ) participated in the regulation of sugar metabolism in leaves and in turn is involved in senescence regulation in Arabidopsis . We show that Nup98a and Nup98b redundantly function in the different steps of starch degradation, the nup98a nup98b double mutant accumulates more starch than wild type and has a severe early senescence phenotype compared to wild type. The expression of marker genes related to starch degradation was impaired in the nup98a nup98b double mutant, and indicator genes of carbon starvation and senescence expressed earlier in the nup98a nup98b double mutant than that in wild type plants, suggesting abnormality of energy metabolism was the cause of senescence of the nup98a nup98b double mutant. Addition of sucrose to the growth medium can rescue early senescence phenotype of the nup98a nup98b mutant. Conclusions: Our results provided a line of evidence on a novel role of the nuclear pore complex in energy metabolism related to growth and development, whereas Nup98 functioned in starch degradation conferring growth regulation in Arabidopsis .

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