Nucleoporin Nup58 Localizes to Centrosomes and Mid-Bodies During Mitosis

Background: Nuclear pore complexes (NPCs) act as nano-turnstiles within nuclear membranes between the cyto- plasm and nucleus of mammalian cells. NPC proteins, called nucleoporins (Nups), mediate trafficking of proteins and RNA into and out of the nucleus, and are involved in a variety of mitotic processes. We previously reported that Nup62 localizes to the centrosome and mitotic spindle during mitosis, and plays a role in centrosome homeostasis.However, whether Nup58, a Nup62 subcomplex protein, also localizes to spindle poles is unknown. Result: Herein, we show that Nup58 localizes to the nuclear rim during interphase, and to mitotic spindles, cen- trosomes, and midbodies during mitosis. Our confocal microscopy, live-cell imaging, and stimulated emission deple- tion nanoscopy results also demonstrated that Nup58 localized to the centrosomes during metaphase and relocalized to midbodies during abscission. Depletion of Nup58 resulted in centrosomal abnormalities and delayed abscission. Conclusion: Nup58 localized at the centrosomes and mitotic spindle during metaphase and relocalized at midbod- ies during abscission. This study highlights the important role of Nup58 in mitosi

The role of nucleoporin Nup58 during mitosis

Nuclear pore complexes (NPCs) are transport channels between the nucleus and the cytoplasm. The NPCs are composed by around 30 different proteins, termed nucleoporins (Nups) and each Nup is present in multiple copies. Recently, we and others discovered that several nucleoporins play critical roles during cell division including chromosome condensation, sister chromatid cohesion, kinetochore assembly and spindle formation. Nup58 is a part of the central transport channel of the NPC, which forms a complex protein with other nucleoporins such as Nup62 and Nup54. Recently, we showed that Nup62 plays a novel role in centrosome integrity. Here, we show that Nup62 interacts with Nup58 during cell mitosis. Next, we performed RNA interference-mediated knockdown of Nup58. Currently, we are investigating nup58 depletion effect in cell cycle

The role of nucleoporin Nup58 during cell division

Nuclear pore complexes (NPCs) are transport channels between the nucleus and the cytoplasm. The NPCs are composed by around 30 different proteins, termed nucleoporins (Nups) and each Nup is present in multiple copies. Recently, we and others discovered that several nucleoporins play critical roles during cell division including chromosome condensation, sister chromatid cohesion, kinetochore assembly and spindle formation. Nup58 is a part of the central transport channel of the NPC, which forms a complex protein with other nucleoporins such as Nup62 and Nup54. Recently, we showed that Nup62 plays a novel role in centrosome integrity. Here, we show that Nup62 interacts with Nup58 during cell mitosis. Next, we performed RNA interference-mediated knockdown of Nup58. Currently, we are investigating Nup58 depletion effect in cell cycle

THE SPATIOTEMPORAL DYNAMICS OF NUCLEOPORIN NUP58 DURING CELL DIVISION

Nuclear pore complexes (NPCs) are transport channels between the nucleus and the cytoplasm. The NPCs are composed by around 30 Nuclear pore complexes (NPCs) are transport channels between the nucleus and the cytoplasm. The NPCs are composed by around 30 different proteins, termed nucleoporins (Nups) and each Nup is present in multiple copies. Recently, we and others discovered that several nucleoporins play critical roles during cell division including centrosome integrity, kinetochore assembly, spindle formation and orientation. Nup58 is a part of the central transport channel of the NPC, which forms a complex protein with other nucleoporins such as Nup62 and Nup54. Where Nup58 localize and what their roles during cell division are still poorly understood. Here, we show that Nup58 localizes at the Nuclear pore complexes (NPCs) are transport channels between the nucleus and the cytoplasm. The NPCs are composed by around 30 different proteins, termed nucleoporins (Nups) and each Nup is present in multiple copies. Recently, we and others discovered that several nucleoporins play critical roles during cell division including centrosome integrity, kinetochore assembly, spindle formation and orientation. Nup58 is a part of the central transport channel of the NPC, which forms a complex protein with other nucleoporins such as Nup62 and Nup54. Where Nup58 localize and what their roles during cell division are still poorly understood. Here, we show that Nup58 localizes at the centrosome during prophase to metaphase, interacting with Nup62, Nup54 and also two centrosome marker protein gamma tubulin and SAS6. Depletion of Nup58 leads to monopolar spindle formation, multi-nucleic cell formation, and delayed cytokinesis. We suggest that Nup58 may regulate cytokinesis abscission. Our study gives novel insight into the role of Nup58 in cell division. centrosome during prophase to metaphase, interacting with Nup62, Nup54 and also two centrosome marker protein gamma tubulin and SAS6. Depletion of Nup58 leads to monopolar spindle formation, multi-nucleic cell formation, and delayed cytokinesis. We suggest that Nup58 may regulate cytokinesis abscission. Our study gives novel insight into the role of Nup58 in cell division. different proteins, termed nucleoporins (Nups) and each Nup is present in multiple copies. Recently, we and others discovered that several nucleoporins play critical roles during cell division including centrosome integrity, kinetochore assembly, spindle formation and orientation. Nup58 is a part of the central transport channel of the NPC, which forms a complex protein with other nucleoporins such as Nup62 and Nup54. Where Nup58 localize and what their roles during cell division are still poorly understood. Here, we show that Nup58 localizes at the centrosome during prophase to metaphase, interacting with Nup62, Nup54 and also two centrosome marker protein gamma tubulin and SAS6. Depletion of Nup58 leads to monopolar spindle formation, multi-nucleic cell formation, and delayed cytokinesis. We suggest that Nup58 may regulate cytokinesis abscission. Our study gives novel insight into the role of Nup58 in cell division

Nucleoporin TPR (Translocated Promoter Region, Nuc;ear Basket Protein) Upregulation Alters MTOR-HSF1 Trails adn Suppresses Autophagy Induction in Ependymoma

Children with ependymoma have high mortality rates because ependymoma is resistant to conventional theraphy. Genomic and transptomic studies have identified potential targets as significantly altered reported, the detailed mechanisms for the roles of these candidate oncogenes in ependymoma progression remain unclear. Here, we report an oncogenic role of the nucleoporin TPR (Translocated promoter region, nuclear basket protein) in regulating HSF1 (Heat Shock Transcription Factor 1) mRNA trafficking, maintaining MTORC1 activity to phosphorylate ULK1, and praventing macroautophagy/autophagy induction in ependymoma. High expression of TPR were associates with inreased HSF1 and HSPA/HSP70 expression in ependymoma patients. In an ependymoma mouse xenohraft model, MTOR inhibition by rapamycin therapeutically suppressed TPR expression and reduced tumor size in vivo. Togetherm these results suggest that TPR may act as a biomarker for ependymoma, and pharmacological interventions targeting TPR-HSF1-MTOR may have therapeutic potential for ependymoma treatment

Direct visualization of avian influenza H5N1 hemagglutinin precursor and its conformational change by high-speed atomic force microscopy

Hemagglutinin (HA) of influenza A is one of the key virulence factors that mediates the release of viral components in host cells. HA is initially synthesized as a trimeric precursor (HA0) and then it is cleaved by proteases to become a functional HA. Low pH induces irreversible conformational changes in both HA0 and HA but only HA is fusion compatible. Here, we used high-speed atomic force microscopy (HS-AFM) to record conformational changes in HA0 trimers (H5N1) from neutral to acidic conditions at a millisecond scale. Methods: Purified HA0 protein was diluted with either neutral Tris-HCl (pH 7.4) or acetic acid-titrated Tris-HCl(pH 5.0) and then loaded onto bare mica. Neutral or acidic Tris-HCl was used as the scanning buffer. HS-AFM movies were recorded and processed using Image J software. Results: The conformation of HA0neutral visualized using HS-AFM was comparable to the HA trimer structures depicted in the PDB data and the AFM simulator. HA0 underwent rapid conformational changes under low pH condition. The circularity and area of HA0acid were significantly higher than in HA0neutral. In contrast, the height of HA0acid was significantly lower than in HA0neutral. Conclusions: We have captured real-time images of the native HA0 trimer structure under physiological conditions using HS-AFM. By analyzing the images, we confirm that HA0 trimer is sensitive to acidic conditions. General significance: The dynamic nature of the HA structure, particularly in the host endosome, is essential for H5N1 infectivity. Understanding this acidic behavior is imperative for designing therapeutic strategies against H5N1. This article reports a sophisticated new tool for studying the spatiotemporal dynamics of the HA precursor protein

Structure–activity relationships and the cytotoxic effects of novel diterpenoid alkaloid derivatives against A549 human lung carcinoma cells

The cytotoxicity of three alkaloids from the roots of Aconitum yesoense var. macroyesoense as well as 36 semi-synthetic C20-diterpenoid atisine-type alkaloid derivatives against A549 human lung carcinoma cells was examined. Ten acylated alkaloid derivatives, pseudokobusine 11-veratroate (9), 11-anisoate (12), 6,11-dianisoate (14), 11-p-nitrobenzoate (18), 11,15-di-p-nitrobenzoate (22), 11-cinnamate (25) and 11-m-trifluoromethylbenzoate (27), and kobusine 11-p-trifluoromethylbenzoate (35), 11-m-trifluoromethylbenzoate (36) and 11,15-di-p-nitrobenzoate (39), exhibited cytotoxic activity, and 11,15-dianisoylpseudokobusine (16) was found to be the most potent cytotoxic agent. Their IC50 values against A549 cells ranged from 1.72 to 5.44 μM. In the occurrence of cytotoxic effects of atisine-type alkaloids, replacement by an acyl group at both C-11 and C-15 resulted in the enhancement of activity of the parent alkaloids compared to that from having hydroxy groups at this position, and the presence of a hydroxy group at the C-6 position was required for the cytotoxic effects. These acylated alkaloid derivatives inhibit cell growth through G1 arrest

Colorectal cancer cells require glycogen synthase kinase-3β for sustaining mitosis via translocated promoter region (TPR)- dynein interaction

金沢大学がん進展制御研究所Glycogen synthase kinase (GSK) 3β, which mediates fundamental cellular signaling pathways, has emerged as a potential therapeutic target for many types of cancer including colorectal cancer (CRC). During mitosis, GSK3β localizes in mitotic spindles and centrosomes, however its function is largely unknown. We previously demonstrated that translocated promoter region (TPR, a nuclear pore component) and dynein (a molecular motor) cooperatively contribute to mitotic spindle formation. Such knowledge encouraged us to investigate putative functional interactions among GSK3β, TPR, and dynein in the mitotic machinery of CRC cells. Here, we show that inhibition of GSK3β attenuated proliferation, induced cell cycle arrest at G2/M phase, and increased apoptosis of CRC cells. Morphologically, GSK3β inhibition disrupted chromosome segregation, mitotic spindle assembly, and centrosome maturation during mitosis, ultimately resulting in mitotic cell death. These changes in CRC cells were associated with decreased expression of TPR and dynein, as well as disruption of their functional colocalization with GSK3β in mitotic spindles and centrosomes. Clinically, we showed that TPR expression was increased in CRC databases and primary tumors of CRC patients. Furthermore, TPR expression in SW480 cells xenografted into mice was reduced following treatment with GSK3β inhibitors. Together, these results indicate that GSK3β sustains steady mitotic processes for proliferation of CRC cells via interaction with TPR and dynein, thereby suggesting that the therapeutic effect of GSK3β inhibition depends on induction of mitotic catastrophe in CRC cells. © Dewi et al.出版社

ROCK-Dependent Phosphorylation of NUP62 Regulates p63 Nuclear Transport and Squamous Cell Carcinoma Proliferation

p63, more specifically its DNp63a isoform, plays essential roles in squamous cell carcinomas (SCCs), yet the mechanisms controlling its nuclear transport remain unknown. Nucleoporins (NUPs) are a family of proteins building nuclear pore complexes (NPC) and mediating nuclear transport across the nuclear envelope. Recent evidence suggests a cell type-specific function for certain NUPs; however, the significance of NUPs in SCC biology remains unknown. In this study, we show that nucleoporin 62 (NUP62) is highly expressed in stratified squamous epithelia and is further elevated in SCCs. Depletion of NUP62 inhibits proliferation and augments differentiation of SCC cells. The impaired ability to main- tain the undifferentiated status is associated with defects in DNp63a nuclear transport. We further find that differentiation- inducible Rho kinase reduces the interaction between NUP62 and DNp63a by phosphorylation of phenylalanine–glycine regions of NUP62, attenuating DNp63a nuclear import. Our results character- ize NUP62 as a gatekeeper for DNp63a and uncover its role in the control of cell fate through regulation of DNp63a nuclear transport in SCC