scholarly journals SnapShot: S-Phase Entry and Exit

Cell ◽  
2019 ◽  
Vol 179 (3) ◽  
pp. 802-802.e1 ◽  
Author(s):  
Andrew Burgess ◽  
Jenny Vuong ◽  
Kamila A. Marzec ◽  
Ulrik Nicolai de Lichtenberg ◽  
Seán I. O’Donoghue ◽  
...  
Keyword(s):  
S Phase ◽  
Entry And Exit ◽  
Phase Entry

scholarly journals E2F-dependent genetic oscillators control endoreplication

2019 ◽  
Author(s):  
Minhee Kim ◽  
Nam-Sung Moon
Keyword(s):  
Feedback Loop ◽  
Target Genes ◽  
S Phase ◽  
Entry And Exit ◽  
Pathological Conditions ◽  
Cdk2 Activity ◽  
Mechanistic Insight ◽  
E2f Transcription Factors ◽  
Phase Entry ◽  
Genetic Oscillators

AbstractPolyploidy is an integral part of development and is associated with cellular stress, aging and pathological conditions. The endoreplication cycle, comprised of successive alternations of G and S phases without cell division, is widely employed to produce polyploid cells. The endocycle is driven by continuous oscillations of Cyclin E/Cdk2 activity, which is governed by E2F transcription factors. In this study, we provide mechanistic insight on how E2F-dependent Cdk oscillations during endocycles are maintained in Drosophila salivary glands. Genetic experiments revealed that an alternative splicing isoform of E2F1, E2F1b, regulates the circuitry of timely S phase entry and exit by activating a subset of E2F target genes. E2F1b regulates the Drosophila ortholog of p27CIP/KIP-like Cdk inhibitor Dacapo to precisely time S phase entry by controlling the CycE/Cdk2 activity threshold. Upon entry to S phase, E2F1b-dependent PCNA expression establishes a negative feedback loop through the PIP box-mediated degradation of E2F1. Overall, our study uncovers a network of E2F-dependent genetic oscillators that are critical for the periodic transition between G and S phases during endoreplication.

scholarly journals Combined Inactivation of Pocket Proteins and APC/CCdh1 by Cdk4/6 Controls Recovery from DNA Damage in G1 Phase

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 550
Author(s):  
Indra A. Shaltiel ◽  
Alba Llopis ◽  
Melinda Aprelia ◽  
Rob Klompmaker ◽  
Apostolos Menegakis ◽  
...  
Keyword(s):  
Dna Damage ◽  
Normal Cell ◽  
S Phase ◽  
G1 Phase ◽  
Anaphase Promoting Complex ◽  
Inhibitory Effects ◽  
Pocket Proteins ◽  
Cyclin Dependent Kinases ◽  
Independent Functions ◽  
Phase Entry

Most Cyclin-dependent kinases (Cdks) are redundant for normal cell division. Here we tested whether these redundancies are maintained during cell cycle recovery after a DNA damage-induced arrest in G1. Using non-transformed RPE-1 cells, we find that while Cdk4 and Cdk6 act redundantly during normal S-phase entry, they both become essential for S-phase entry after DNA damage in G1. We show that this is due to a greater overall dependency for Cdk4/6 activity, rather than to independent functions of either kinase. In addition, we show that inactivation of pocket proteins is sufficient to overcome the inhibitory effects of complete Cdk4/6 inhibition in otherwise unperturbed cells, but that this cannot revert the effects of Cdk4/6 inhibition in DNA damaged cultures. Indeed, we could confirm that, in addition to inactivation of pocket proteins, Cdh1-dependent anaphase-promoting complex/cyclosome (APC/CCdh1) activity needs to be inhibited to promote S-phase entry in damaged cultures. Collectively, our data indicate that DNA damage in G1 creates a unique situation where high levels of Cdk4/6 activity are required to inactivate pocket proteins and APC/CCdh1 to promote the transition from G1 to S phase.

scholarly journals NKX3.1 contributes to S phase entry and regulates DNA damage response (DDR) in prostate cancer cell lines

2011 ◽  
Vol 414 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Burcu Erbaykent-Tepedelen ◽  
Besra Özmen ◽  
Lokman Varisli ◽  
Ceren Gonen-Korkmaz ◽  
Bilge Debelec-Butuner ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Dna Damage ◽  
Cell Lines ◽  
Cancer Cell ◽  
Dna Damage Response ◽  
Prostate Cancer Cell ◽  
S Phase ◽  
Prostate Cancer Cell Lines ◽  
Damage Response ◽  
Phase Entry

scholarly journals Phosphoinositide 3-Kinases p110α and p110β Regulate Cell Cycle Entry, Exhibiting Distinct Activation Kinetics in G1 Phase

2008 ◽  
Vol 28 (8) ◽  
pp. 2803-2814 ◽  
Author(s):  
Miriam Marqués ◽  
Amit Kumar ◽  
Isabel Cortés ◽  
Ana Gonzalez-García ◽  
Carmen Hernández ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Tyrosine Kinases ◽  
Control Cell ◽  
Growth Factor Receptor ◽  
Maximum Activity ◽  
S Phase ◽  
Selective Action ◽  
Cell Cycle Entry ◽  
Phosphoinositide 3 Kinase ◽  
Phase Entry

ABSTRACT Phosphoinositide 3-kinase (PI3K) is an early signaling molecule that regulates cell growth and cell cycle entry. PI3K is activated immediately after growth factor receptor stimulation (at the G0/G1 transition) and again in late G1. The two ubiquitous PI3K isoforms (p110α and p110β) are essential during embryonic development and are thought to control cell division. Nonetheless, it is presently unknown at which point each is activated during the cell cycle and whether or not they both control S-phase entry. We found that p110α was activated first in G0/G1, followed by a minor p110β activity peak. In late G1, p110α activation preceded that of p110β, which showed the maximum activity at this time. p110β activation required Ras activity, whereas p110α was first activated by tyrosine kinases and then further induced by active Ras. Interference with p110α and -β activity diminished the activation of downstream effectors with different kinetics, with a selective action of p110α in blocking early G1 events. We show that inhibition of either p110α or p110β reduced cell cycle entry. These results reveal that PI3Kα and -β present distinct activation requirements and kinetics in G1 phase, with a selective action of PI3Kα at the G0/G1 phase transition. Nevertheless, PI3Kα and -β both regulate S-phase entry.

scholarly journals Cyclin A Promotes S-Phase Entry via Interaction with the Replication Licensing Factor Mcm7

2010 ◽  
Vol 31 (2) ◽  
pp. 248-255 ◽  
Author(s):  
T. Chibazakura ◽  
K. Kamachi ◽  
M. Ohara ◽  
S. Tane ◽  
H. Yoshikawa ◽  
...  
Keyword(s):  
Cyclin A ◽  
S Phase ◽  
Licensing Factor ◽  
Phase Entry

scholarly journals GSK-3 promotes S-phase entry and progression inC. elegansgermline stem cells to maintain tissue output

Development ◽  
2018 ◽  
Vol 145 (10) ◽  
pp. dev161042 ◽  
Author(s):  
Tokiko Furuta ◽  
Hyoe-Jin Joo ◽  
Kenneth A. Trimmer ◽  
Shin-Yu Chen ◽  
Swathi Arur
Keyword(s):  
Stem Cells ◽  
S Phase ◽  
Phase Entry

scholarly journals Control of timing of embryonic M-phase entry and exit is differentially sensitive to CDK1 and PP2A balance

2014 ◽  
Vol 58 (10-11-12) ◽  
pp. 767-774 ◽  
Author(s):  
Mohammed El Dika ◽  
Damian Dudka ◽  
Claude Prigent ◽  
Jean-Pierre Tassan ◽  
Malgorzata Kloc ◽  
...  
Keyword(s):  
Entry And Exit ◽  
M Phase ◽  
Phase Entry
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