scholarly journals Cytoplasmic nucleophosmin has elevated T199 phosphorylation upon which G2/M phase progression is dependent

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Narisa Chan ◽  
Tit Meng Lim
Keyword(s):  
M Phase ◽  
Phase Progression

Fyn Accelerates M Phase Progression by Promoting the Assembly of Mitotic Spindle Microtubules

2015 ◽  
Vol 117 (4) ◽  
pp. 894-903 ◽  
Author(s):  
Mai Okamoto ◽  
Yuji Nakayama ◽  
Ayana Kakihana ◽  
Ryuzaburo Yuki ◽  
Noritaka Yamaguchi ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
M Phase ◽  
Phase Progression ◽  
Spindle Microtubules

scholarly journals Mitotic Expression of Spo13 Alters M-Phase Progression and Nucleolar Localization of Cdc14 in Budding Yeast

Genetics ◽  
2010 ◽  
Vol 185 (3) ◽  
pp. 841-854 ◽  
Author(s):  
Elisa Varela ◽  
Ulrich Schlecht ◽  
Anca Moina ◽  
James D. Fackenthal ◽  
Brian K. Washburn ◽  
...  
Keyword(s):  
Budding Yeast ◽  
Nucleolar Localization ◽  
M Phase ◽  
Phase Progression

scholarly journals Mutant Caldesmon Lacking cdc2 Phosphorylation Sites Delays M-Phase Entry and Inhibits Cytokinesis

2001 ◽  
Vol 12 (1) ◽  
pp. 239-250 ◽  
Author(s):  
Shigeko Yamashiro ◽  
Hueylan Chern ◽  
Yoshihiko Yamakita ◽  
Fumio Matsumura
Keyword(s):  
Cho Cells ◽  
Kinase Activity ◽  
Chinese Hamster ◽  
Phosphorylation Sites ◽  
Wild Type ◽  
Cdc2 Kinase ◽  
Effective Inhibition ◽  
M Phase ◽  
Phase Progression ◽  
Phase Entry

Caldesmon is phosphorylated by cdc2 kinase during mitosis, resulting in the dissociation of caldesmon from microfilaments. To understand the physiological significance of phosphorylation, we generated a caldesmon mutant replacing all seven cdc2 phosphorylation sites with Ala, and examined effects of expression of the caldesmon mutant on M-phase progression. We found that microinjection of mutant caldesmon effectively blocked early cell division ofXenopus embryos. Similar, though less effective, inhibition of cytokinesis was observed with Chinese hamster ovary (CHO) cells microinjected with 7th mutant. When mutant caldesmon was introduced into CHO cells either by protein microinjection or by inducible expression, delay of M-phase entry was observed. Finally, we found that 7th mutant inhibited the disassembly of microfilaments during mitosis. Wild-type caldesmon, on the other hand, was much less potent in producing these three effects. Because mutant caldesmon did not inhibit cyclin B/cdc2 kinase activity, our results suggest that alterations in microfilament assembly caused by caldesmon phosphorylation are important for M-phase progression.

scholarly journals Different Plk1 Functions Show Distinct Dependencies on Polo-Box Domain-mediated Targeting

2006 ◽  
Vol 17 (1) ◽  
pp. 448-459 ◽  
Author(s):  
Anja Hanisch ◽  
Anja Wehner ◽  
Erich A. Nigg ◽  
Herman H.W. Silljé
Keyword(s):  
Catalytic Domain ◽  
Mitotic Arrest ◽  
Binding Motif ◽  
Subcellular Targeting ◽  
Chromosome Congression ◽  
M Phase ◽  
Phase Progression ◽  
In Cells

Polo-like kinase 1 (Plk1) has multiple important functions during M-phase progression. In addition to a catalytic domain, Plk1 possesses a phosphopeptide-binding motif, the polo-box domain (PBD), which is required for proper localization. Here, we have explored the importance of correct Plk1 subcellular targeting for its mitotic functions. We either displaced endogenous Plk1 through overexpression of the PBD or introduced the catalytic domain of Plk1, lacking the PBD, into Plk1-depleted cells. Both treatments resulted in remarkably similar phenotypes, which were distinct from the Plk1 depletion phenotype. Cells depleted of Plk1 mostly arrested with monoastral spindles, because of inhibition of centrosome maturation and separation. In contrast, these functions were not impaired in cells with mislocalized Plk1. Instead, these latter cells showed a checkpoint-dependent mitotic arrest characterized by impaired chromosome congression. Thus, whereas chromosome congression requires localized Plk1 activity, other investigated Plk1 functions are less dependent on correct PBD-mediated targeting. This opens the possibility that PBD-directed drugs might be developed to selectively interfere with a subset of Plk1 functions.

scholarly journals Cyclin A2/Cdk1 is Essential for the in vivo S Phase Entry by Phosphorylating Top2a

2019 ◽  
Author(s):  
Miaomiao Jin ◽  
Ruikun Hu ◽  
Baijie Xu ◽  
Weilai Huang ◽  
Hong Wang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclin B1 ◽  
S Phase ◽  
Downstream Target ◽  
Early Embryonic Lethality ◽  
M Phase ◽  
Phase Progression ◽  
Cyclin A2 ◽  
Phase Entry

AbstractCyclin-dependent kinase 1 (CDK1) plays essential roles in cell cycle regulation. However, due to the early embryonic lethality of mouse Cdk1 mutants, the in vivo role of CDK1 in regulating cell cycle and embryonic development remains unclear. Here, by generating zebrafish cdk1 mutants using CRISPR/Cas9 system, we show that cdk1−/− embryos exhibit severe microphthalmia accompanied with multiple defects in polarized cell division, S phase entry and M phase progression, cell apoptosis and cell differentiation, but not in interkinetic nuclear migration (IKNM). By informatics analysis, we identified Top2a as a potential downstream target, and Cyclin A2 and Cyclin B1 as partners of Cdk1 in cell cycle. Depletion of either Cyclin A2 or Top2a leads to decreased S phase entry and increased DNA damage response in zebrafish retinal cells, and depletion of Cyclin B1 leads to M phase arrest. Immunoprecipitation shows that Cdk1 and Cyclin A2 physically interact in vivo. Moreover, phosphorylation of Top2a on Serine 1213 (S1213) site is almost absent in either cdk1 or ccna2 mutants, but in not ccnb1 mutants. Furthermore, overexpression of TOP2AS1213, the phosphomimetic form of human TOP2A, rescues S phase entry and microphthalmia defects in cdk1−/− and ccna2−/− embryos. Taken together, our data suggests that Cdk1 interacts with Cyclin A2 to regulate S phase entry through phosphorylating Top2a, and with Cyclin B1 to regulate M phase progression in vivo.

Identification and targeting of M-phase progression downstream of HER2 in trastuzumab-sensitive and -resistant breast cancer cell lines.

2014 ◽  
Vol 32 (15_suppl) ◽  
pp. 612-612
Author(s):  
E. Aubrey Thompson ◽  
Brian M. Necela ◽  
Jennifer M. Carr ◽  
Jennifer M. Kachergus ◽  
Daniel Serie ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Lines ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Cancer Cell Lines ◽  
Breast Cancer Cell Lines ◽  
M Phase ◽  
Phase Progression ◽  
Resistant Breast Cancer Cell

scholarly journals Mammalian Polo-like Kinase 1-dependent Regulation of the PBIP1-CENP-Q Complex at Kinetochores

2011 ◽  
Vol 286 (22) ◽  
pp. 19744-19757 ◽  
Author(s):  
Young H. Kang ◽  
Chi Hoon Park ◽  
Tae-Sung Kim ◽  
Nak-Kyun Soung ◽  
Jeong K. Bang ◽  
...  
Keyword(s):  
Complex Formation ◽  
Ternary Complex ◽  
Pivotal Role ◽  
Spindle Formation ◽  
Bipolar Spindle ◽  
Chromosome Missegregation ◽  
M Phase ◽  
Phosphorylation Event ◽  
Phase Progression ◽  
Unique Mechanism

Mammalian polo-like kinase 1 (Plk1) plays a pivotal role during M-phase progression. Plk1 localizes to specific subcellular structures through the targeting activity of the C-terminal polo-box domain (PBD). Disruption of the PBD function results in improper bipolar spindle formation, chromosome missegregation, and cytokinesis defect that ultimately lead to the generation of aneuploidy. It has been shown that Plk1 recruits itself to centromeres by phosphorylating and binding to a centromere scaffold, PBIP1 (also called MLF1IP and CENP-U[50]) through its PBD. However, how PBIP1 itself is targeted to centromeres and what roles it plays in the regulation of Plk1-dependent mitotic events remain unknown. Here, we demonstrated that PBIP1 directly interacts with CENP-Q, and this interaction was mutually required not only for their stability but also for their centromere localization. Plk1 did not appear to interact with CENP-Q directly. However, Plk1 formed a ternary complex with PBIP1 and CENP-Q through a self-generated p-T78 motif on PBIP1. This complex formation was central for Plk1-dependent phosphorylation of PBIP1-bound CENP-Q and delocalization of the PBIP1-CENP-Q complex from mitotic centromeres. This study reveals a unique mechanism of how PBIP1 mediates Plk1-dependent phosphorylation event onto a third protein, and provides new insights into the mechanism of how Plk1 and its recruitment scaffold, PBIP1-CENP-Q complex, are localized to and delocalized from centromeres.

ERK Plays a Role in Chromosome Alignment and Participates in M-Phase Progression

2015 ◽  
Vol 117 (6) ◽  
pp. 1340-1351 ◽  
Author(s):  
Erika Iwamoto ◽  
Natsumi Ueta ◽  
Yuki Matsui ◽  
Keiju Kamijo ◽  
Takahisa Kuga ◽  
...  
Keyword(s):  
Chromosome Alignment ◽  
M Phase ◽  
Phase Progression
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