Cover Image, Volume 237, Number 1, January 2022 Chiu, Shao‐Chih; Huang, Yun‐Ru Jaoying; Wei, Tong‐You Wade ...
Journal of cellular physiology,
01/2022, Volume:
237, Issue:
1
Journal Article
Peer reviewed
Inside Back Cover: The cover image is based on the Research Article The PRMT5/HURP axis retards Golgi repositioning by stabilizing acetyl‐tubulin and Golgi apparatus during cell migration by ...Chang‐Tze Ricky Yu et al., https://doi.org/10.1002/jcp.30589.
p53 plays an important role in mitotic checkpoint, but what its role is remains enigmatic. Aurora A is a Ser/Thr kinase involved in correcting progression of mitosis. Here, we show that p53 is a ...negative regulator for Aurora A. We found that p53 deficiency leads to Aurora A elevation. Ectopic expression of p53 or DNA damage-induced expression of p53 can suppress the expression of Aurora A. Mechanistic studies show that p53 is a negative regulator for Aurora A expression through both transcriptional and posttranslational regulation. p53 knockdown in cancer cells reduces the level of p21, which, in turn, increases the activity of CDK2 followed by induction of Rb1 hyperphosphorylation and its dissociation with transcriptional factor E2F3. E2F3 can bind to Aurora A gene promoter, potentiating Aurora A gene expression and p53 deficiency, enhancing the binding of E2F3 on Aurora A promoter. Also, p53 deficiency leads to decelerating Aurora A's turnover rate, due to the fact that p53 deficiency causes the downregulation of Fbw7α, a component of E3 ligase of Aurora A. Consistently, p53 knockdown-mediated Aurora A elevation is mitigated when Fbw7α is ectopically expressed. Thus, p53-mediated Aurora A degradation requires Fbw7α expression. Significantly, inverse correlation between p53 and Aurora A elevation is translated into the deregulation of centrosome amplification. p53 knockdown leads to high percentages of cells with abnormal amplification of centrosome. These data suggest that p53 is an important negative regulator of Aurora A, and that loss of p53 in many types of cancer could lead to abnormal elevation of Aurora A and dysregulated mitosis, which provides a growth advantage for cancer cells.
•A facile two-steps electroless deposition for uniformly decorating the Ag nanoparticles on the highly aspect ratio of Si nanowire arrays was demonstrated.•Systematic explorations of SERS capability ...and antibacterial activity of the Ag/Si-incorporated nanostructures were performed.•The optimized Ag loadings on Si nanowire-based substrates for the inhibited growth of E. coli bacteria were investigated.
We present a facile, reliable and controllable two-steps electroless deposition for uniformly decorating the silver (Ag) nanoparticles (NPs) on the highly aspect ratio of silicon (Si) nanowire arrays. Different from the direct Ag-loading process, which is normally challenged by the non-uniform coating of Ag, the formation of Ag NPs using such innovative electroless process is no longer to be limited at top nanowire surfaces solely; instead, each Ag+/Si interface can initiate the galvanic reduction of Ag+ ions, thus resulting in the uniform formation of Ag NPs on the entire Si nanowire arrays. In addition, systematic explorations of surface-enhanced Raman scattering (SERS) capability as well as antibacterial activity of the Ag/Si-incorporated nanostructures were performed, and the optimized Ag loadings on Si nanowire-based substrates along with the kinetic investigations were further revealed, which may benefit their practical applications in sensing, medical and biological needs.
Mitosis is a complicated process by which eukaryotic cells segregate duplicated genomes into two daughter cells. To achieve the goal, numerous regulators have been revealed to control mitosis. The ...oncogenic Aurora-A is a versatile kinase responsible for the regulation of mitosis including chromosome condensation, spindle assembly, and centrosome maturation through phosphorylating a range of substrates. However, overexpression of Aurora-A bypasses cytokinesis, thereby generating multiple nuclei by unknown the mechanisms. To explore the underlying mechanisms, we found that SLAN, a potential tumor suppressor, served as a substrate of Aurora-A and knockdown of SLAN induced immature cytokinesis. Aurora-A phosphorylates SLAN at T573 under the help of the scaffold protein 14-3-3η. The SLAN phosphorylation-mimicking mutants T573D or T573E, in contrast to the phosphorylation-deficiency mutant T573A, induced higher level of multinucleated cells, and the endogenous SLAN p573 resided at spindle midzone and midbody with the help of the microtubule motor MKLP1. The Aurora-A- or SLAN-induced multiple nuclei was prevented by the knockdown of 14-3-3η or Aurora-A respectively, thereby revealing a 14-3-3η/Aurora-A/SLAN cascade negatively controlling cytokinesis. Intriguingly, SLAN T573D or T573E inactivated and T573A activated the key cytokinesis regulator RhoA. RhoA interacted with SLAN np573, i.e., the nonphosphorylated form of SLAN at T573, which localized to the spindle midzone dictated by RhoA and ECT2. Therefore, we report here that SLAN mediates the Aurora-A-triggered cytokinesis bypass and SLAN plays dual roles in that process depending on its phosphorylation status.
ZnO nanorods (NRs) incorporating a graphene layer were fabricated on silicon substrates. The graphene layer was placed on top and bottom of ZnO to form graphene/ZnO NRs/Si and ZnO NRs/graphene/Si ...nanocomposites. To characterize these nanocomposites, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction were used, as well as contact angle measurements to study hydrophilic properties. Finally, OD600 bacterial growth tests were performed to investigate the bacterial suppression capabilities. Results indicate that the ZnO NRs/graphene/Si nanocomposite exhibits the strongest bacterial suppression capability among the studied nanostructures.
A distinctive novel ZnO/ZnS core-shell structure on silicon was reported in this study. Compared with previous studies, ZnO nanorods encapsulated by 5 nm ZnS nanograins were observed using a scanning ...electron microscope. Furthermore, strong (111) cubic ZnS crystalline structures were confirmed using high resolution transmission electron microscopy, selected area diffraction, and X-ray diffraction. The optical properties changed and the antibacterial behaviors were suppressed as the ZnS shells were attached onto the ZnO nanorods. Moreover, the results also indicate that the hydrophobicity could be enhanced as more ZnS nanograins were wrapped onto the ZnO nanorods. The ZnO/ZnS core-shell structures in this research show promise for use in future optoelectronic and biomedical applications.
A distinctive novel ZnO/ZnS core-shell structure on silicon was reported in this study.
Methylosome protein 50 (MEP50) is a component of methylosome where MEP50 binds protein substrates and activates the oncogenic protein arginine methyl transferase 5 (PRMT5). MEP50 is also a ...coactivator for androgen receptor (AR) and estrogen receptor (ER), and transforms cells in the presence of androgen or estrogen. To extend the understanding of how MEP50 transforms cells, we investigated whether MEP50 could transform cells independent of AR and ER, and clarified whether PRMT5 could contribute to the MEP50-caused tumor formation. Microarray and Western blot analyses revealed the association of MEP50 with many human cancers including lung cancer. Knockdown of MEP50 retarded cell growth and migration in selected lung cancer cell lines, which expressed very low level of AR and ER and were insensitive to inhibitors of AR and ER. Moreover, overexpression of Myc-MEP50 enhanced cell transforming activities of 293T cells which are known lack of expression of AR and ER. Mechanistic analyses showed that MEP50 controlled G2 progression, upregulated cyclin-dependent kinase 1(CDK1)/cyclin B1, and activated the survival cascade Phosphoinositide 3-kinase (PI3K)/AKT. MEP50 promoted cell migration, and activated the cell migration pathways such as Ras-related C3 botulinum toxin substrate 1 (Rac1)/vasodilator-stimulated phosphoprotein (VASP), and forkhead box protein A2 (FOXA2)/slug/cadherin cascades. Further analyses revealed that MEP50 activated the survival factor PI3K through PRMT5-catalyzed dimethylation of PI3K. Collectively, it is concluded that MEP50 can transform cells independent of AR and ER, and PRMT5 has partial contribution to that process.
•MEP50 promotes cell transforming activities of lung cancer cell lines with limited ER or AR activity.•MEP50 transforms 293T cells which do not express ER and AR.•MEP50 stimulates G2 progression and upregulates CDK1 and cyclin B in 293T.•MEP50 enhances cell migration by adopting Rac1/VASP and FOXA2/Slug/Cadherins cascades in 293T.•MEP50 promotes cell survival by employing PRMT5/PI3K in 293T.
In this study, zinc oxide nanostructures integrated with reduced graphene oxide (RGO) were fabricated on foldable indium tin oxide substrates. To study the influence of RGO on the material, ...antibacterial, and piezoelectric properties on the nanostructures, multiple material, antibacterial, and electrical measurements were performed. Results indicate that inserting a RGO layer on the foldable substrate could form nanocylinder ZnO structures, which induced hydrophobicity and better antibacterial properties. Moreover, addition of appropriate RGO into ZnO seed layer may cause the growth of finer ZnO nanorods (NRs) and enhance piezoelectric effects. With stable electrical pulse generative piezoelectric effects and antibacterial properties, ZnO nanostructures with addition of RGO on foldable substrates have potential for future flexible biomedical and electronics applications.
Cells display dramatic morphological changes in mitosis, where numerous factors form regulatory networks to orchestrate the complicated process, resulting in extreme fidelity of the segregation of ...duplicated chromosomes into two daughter cells. Astrin regulates several aspects of mitosis, such as maintaining the cohesion of sister chromatids by inactivating Separase and stabilizing spindle, aligning and segregating chromosomes, and silencing spindle assembly checkpoint by interacting with Src kinase-associated phosphoprotein (SKAP) and cytoplasmic linker-associated protein-1α (CLASP-1α). To understand how Astrin is regulated in mitosis, we report here that Astrin acts as a mitotic phosphoprotein, and Aurora-A phosphorylates Astrin at Ser(115). The phosphorylation-deficient mutant Astrin S115A abnormally activates spindle assembly checkpoint and delays mitosis progression, decreases spindle stability, and induces chromosome misalignment. Mechanistic analyses reveal that Astrin phosphorylation mimicking mutant S115D, instead of S115A, binds and induces ubiquitination and degradation of securin, which sequentially activates Separase, an enzyme required for the separation of sister chromatids. Moreover, S115A fails to bind mitosis regulators, including SKAP and CLASP-1α, which results in the mitotic defects observed in Astrin S115A-transfected cells. In conclusion, Aurora-A phosphorylates Astrin and guides the binding of Astrin to its cellular partners, which ensures proper progression of mitosis.
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