scholarly journals CDK1 phosphorylates ULK1-ATG13 complex to regulate mitotic autophagy and Taxol chemosensitivity

2019 ◽  
Author(s):  
Zhiyuan Li ◽  
Xiaofei Tian ◽  
Xinmiao Ji ◽  
Dongmei Wang ◽  
Xin Zhang
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Site Directed Mutagenesis ◽  
Regulation Mechanism ◽  
Cancer Cell Proliferation ◽  
Double Knockout ◽  
Cycle Progression ◽  
Mutual Regulation ◽  
Block Cell Cycle Progression ◽  
And Function

AbstractULK1-ATG13 is the most upstream autophagy initiation complex that is phosphorylated by mTORC1 and AMPK to induce autophagy in asynchronous conditions. However, the phospho-regulation and function of ULK1-ATG13 in mitosis and cell cycle remains unknown. Here we show that ULK1-ATG13 complex is differentially regulated throughout the cell cycle. Notably, in mitosis, both ULK1 and ATG13 are highly phosphorylated by CDK1/cyclin B, the key cell cycle machinery. Combining mass spectrometry and site-directed mutagenesis, we found that CDK1-induced ULK1-ATG13 phosphorylation positively regulates mitotic autophagy and Taxol chemosensitivity, and some phosphorylation sites occur in cancer patients. Moreover, double knockout of ULK1 and ATG13 could block cell cycle progression and significantly decrease cancer cell proliferation in cell line and mouse models. Our results not only bridge the mutual regulation between the core machineries of autophagy and mitosis, illustrate the mitotic autophagy regulation mechanism, but also provide ULK1-ATG13 as potential targets for cancer therapy.

scholarly journals Distinct Cell Cycle Timing Requirements for Extracellular Signal-Regulated Kinase and Phosphoinositide 3-Kinase Signaling Pathways in Somatic Cell Mitosis

2002 ◽  
Vol 22 (20) ◽  
pp. 7226-7241 ◽  
Author(s):  
Elisabeth C. Roberts ◽  
Paul S. Shapiro ◽  
Theresa Stines Nahreini ◽  
Gilles Pages ◽  
Jacques Pouyssegur ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Cyclin B1 ◽  
Erk Pathway ◽  
Cycle Progression ◽  
Mitotic Entry ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Phosphoinositide 3 Kinase ◽  
And Function

ABSTRACT Mitogen-activated protein (MAP) kinase and phosphoinositide 3-kinase (PI3K) pathways are necessary for cell cycle progression into S phase; however the importance of these pathways after the restriction point is poorly understood. In this study, we examined the regulation and function of extracellular signal-regulated kinase (ERK) and PI3K during G2/M in synchronized HeLa and NIH 3T3 cells. Phosphorylation and activation of both the MAP kinase kinase/ERK and PI3K/Akt pathways occur in late S and persist until the end of mitosis. Signaling was rapidly reversed by cell-permeable inhibitors, indicating that both pathways are continuously activated and rapidly cycle between active and inactive states during G2/M. The serum-dependent behavior of PI3K/Akt versus ERK pathway activation indicates that their mechanisms of regulation differ during G2/M. Effects of cell-permeable inhibitors and dominant-negative mutants show that both pathways are needed for mitotic progression. However, inhibiting the PI3K pathway interferes with cdc2 activation, cyclin B1 expression, and mitotic entry, whereas inhibiting the ERK pathway interferes with mitotic entry but has little effect on cdc2 activation and cyclin B1 and retards progression from metaphase to anaphase. Thus, our study provides novel evidence that ERK and PI3K pathways both promote cell cycle progression during G2/M but have different regulatory mechanisms and function at distinct times.

scholarly journals Structural mechanism of Myb–MuvB assembly

2018 ◽  
Vol 115 (40) ◽  
pp. 10016-10021 ◽  
Author(s):  
Keelan Z. Guiley ◽  
Audra N. Iness ◽  
Siddharth Saini ◽  
Sarvind Tripathi ◽  
Joseph S. Lipsick ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Biochemical Analysis ◽  
Adaptor Protein ◽  
Cancer Cell Proliferation ◽  
Cycle Progression ◽  
Structural Mechanism ◽  
Transcriptional Regulatory ◽  
Regulatory Complex ◽  
Cycle Dependent

The MuvB transcriptional regulatory complex, which controls cell-cycle-dependent gene expression, cooperates with B-Myb to activate genes required for the G2 and M phases of the cell cycle. We have identified the domain in B-Myb that is essential for the assembly of the Myb–MuvB (MMB) complex. We determined a crystal structure that reveals how this B-Myb domain binds MuvB through the adaptor protein LIN52 and the scaffold protein LIN9. The structure and biochemical analysis provide an understanding of how oncogenic B-Myb is recruited to regulate genes required for cell-cycle progression, and the MMB interface presents a potential therapeutic target to inhibit cancer cell proliferation.

scholarly journals Tyr198 is the Essential Autophosphorylation Site for STK16 Localization and Kinase Activity

2019 ◽  
Vol 20 (19) ◽  
pp. 4852 ◽  
Author(s):  
Junjun Wang ◽  
Juanjuan Liu ◽  
Xinmiao Ji ◽  
Xin Zhang
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Kinase Activity ◽  
Kinase Domain ◽  
Serine Threonine Kinase ◽  
Cycle Progression ◽  
Threonine Kinase ◽  
Cellular Processes ◽  
Activation Segment ◽  
And Function

STK16, reported as a Golgi localized serine/threonine kinase, has been shown to participate in multiple cellular processes, including the TGF-β signaling pathway, TGN protein secretion and sorting, as well as cell cycle and Golgi assembly regulation. However, the mechanisms of the regulation of its kinase activity remain underexplored. It was known that STK16 is autophosphorylated at Thr185, Ser197, and Tyr198 of the activation segment in its kinase domain. We found that STK16 localizes to the cell membrane and the Golgi throughout the cell cycle, but mutations in the auto-phosphorylation sites not only alter its subcellular localization but also affect its kinase activity. In particular, the Tyr198 mutation alone significantly reduced the kinase activity of STK16, abolished its Golgi and membrane localization, and affected the cell cycle progression. This study demonstrates that a single site autophosphorylation of STK16 could affect its localization and function, which provides insights into the molecular regulatory mechanism of STK16’s kinase activity.

scholarly journals Role of Baculovirus IE2 and Its RING Finger in Cell Cycle Arrest

1998 ◽  
Vol 72 (1) ◽  
pp. 684-692 ◽  
Author(s):  
Elena A. Prikhod’ko ◽  
Lois K. Miller
Keyword(s):  
Cell Cycle ◽  
Trichoplusia Ni ◽  
Helicoverpa Zea ◽  
Cell Cycle Progression ◽  
Ring Finger ◽  
Regulatory Activity ◽  
Cycle Progression ◽  
Dna Contents ◽  
Block Cell Cycle Progression ◽  
Ring Finger Motif

ABSTRACT The ie2 gene of Autographa californicanuclear polyhedrosis virus (AcMNPV) is known to transactivate transient expression from viral promoters in a host cell-specific manner. We report that transfection ofSpodoptera frugiperda (SF-21) cells with ie2was sufficient to arrest the cell cycle, resulting in the accumulation of enlarged cells with abnormally high DNA contents. By 72 h posttransfection, more than 50% of ie2-transfected cells had DNA contents greater than 4N. There was no evidence of mitotic spindle formation in these cells, and expression ofie2 appeared to block cell cycle progression in S phase. Several ie2 mutants were analyzed to further define the region of IE2 responsible for arresting the cell cycle. Analysis of these mutants showed that deletion of the RING finger motif eliminated the ability of IE2 to arrest the cell cycle but did not affect its ability to transactivate the ie1 promoter. Moreover, mutation of a single conserved cysteine (C251) of the RING finger motif abolished the ability of IE2 to block cell cycle progression but had no apparent effect on its trans-regulatory activity. In contrast, a mutant of IE2 containing a deletion of residues 94 to 173 was able to block cell division but lacked trans-regulatory activity. Thus, the ability of IE2 to arrest the cell cycle depended on the integrity of the RING finger motif and was distinct from and independent of its ability to trans-activate theie1 promoter. IE2 also arrested the division of cells derived from other insect species, Trichoplusia ni (TN-368 and BTI-TN-5B1-4) and Helicoverpa zea (Hz-AM1).

scholarly journals LncRNA EPIC1 Promotes Cancer Cell Proliferation and Inhibits Apoptosis in Gallbladder Cancer Interacting with lncRNA LET

2020 ◽  
Author(s):  
Changbo Fu ◽  
Lei Nie ◽  
Tao Yin ◽  
Xuan Xu ◽  
weijun lu
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Gallbladder Cancer ◽  
Cancer Cell ◽  
Cell Cycle Progression ◽  
Human Cancer ◽  
Cancer Cell Proliferation ◽  
Cycle Progression ◽  
Tumor Tissues ◽  
Proliferation And Apoptosis

Abstract Background: LncRNA EPIC1 is likely involved in human cancer by promoting cell cycle progression. Our study was carried out to investigate the involvement of EPIC1 in gallbladder cancer (GBC). Methods: Expression levels of EPIC1 in two types of tissues (GBC and paracancerous) and plasma were measured by performing qPCR. GBC-SD and SGC-996 cells were transfected with LET and EPIC1 expression vectors.Results: In the preset study we found that EPIC1 was upregulated in tumor tissues than in paracancerous tissues of GBC patients, and plasma levels of EPIC1 were significantly correlated with levels of EPIC1 in tumor tissues. LncRNA LET was downregulated in tumor tissues than in paracancerous tissues and was inversely correlated with EPIC1 in both tumor tissues and paracancerous tissues. Overexpression of EPIC1 led to downregulated LET, and LET overexpression also mediated the downregulation of EPIC1. EPIC1 led to accelerated GBC cell proliferation and inhibited apoptosis. Overexpression of LET played opposites roles. In addition, overexpression of LET also attenuated the effects of EPIC1 overexpression on cancer cell proliferation and apoptosis. Conclusion: Therefore, therefore, lncRNA EPIC1 may promote cancer cell proliferation and inhibit apoptosis in GBC by interacting with LET.

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