scholarly journals Varicella-Zoster Virus ORF12 Protein Activates the Phosphatidylinositol 3-Kinase/Akt Pathway To Regulate Cell Cycle Progression

2012 ◽  
Vol 87 (3) ◽  
pp. 1842-1848 ◽  
Author(s):  
XueQiao Liu ◽  
Jeffrey I. Cohen
Keyword(s):  
Cell Cycle ◽  
Deletion Mutant ◽  
Cell Cycle Progression ◽  
Phase Cell ◽  
Akt Pathway ◽  
Wild Type ◽  
Cycle Progression ◽  
Varicella Zoster ◽  
M Phase ◽  
Regulate Cell Cycle Progression

ABSTRACTVaricella-zoster virus (VZV) activates the phosphatidylinositol 3-kinase (PI3K)/Akt pathway and alters cell cycle progression, but the viral protein(s) responsible for these activities is unknown. We previously reported that the VZV open reading frame 12 (ORF12) protein triggers phosphorylation of ERK. Here, we demonstrate that the VZV ORF12 protein also activates the PI3K/Akt pathway to regulate cell cycle progression. Transfection of cells with a plasmid expressing the ORF12 protein induced phosphorylation of Akt, which was dependent on PI3K. Infection of cells with wild-type VZV triggered phosphorylation of Akt, while infection with an ORF12 deletion mutant induced less phosphorylated Akt. The activation of Akt by ORF12 protein was associated with its binding to the p85 subunit of PI3K. Infection of cells with wild-type VZV resulted in increased levels of cyclin B1, cyclin D3, and phosphorylated glycogen synthase kinase 3β (GSK-3β), while infection with the ORF12 deletion mutant induced lower levels of these proteins. Wild-type VZV infection reduced the G1phase cell population and increased the M phase cell population, while infection with the ORF12 deletion mutant had a reduced effect on the G1and M phase populations. Inhibition of Akt activity with LY294002 reduced the G1and M phase differences observed in cells infected with wild-type and ORF12 mutant viruses. In conclusion, we have found that the VZV ORF12 protein activates the PI3K/Akt pathway to regulate cell cycle progression. Since VZV replicates in both dividing (e.g., keratinocytes) and nondividing (neurons) cells, the ability of the VZV ORF12 protein to regulate the cell cycle is likely important for VZV replication in various cell types in the body.

scholarly journals Regulation of Cell Cycle Progression by Growth Factor-Induced Cell Signaling

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3327
Author(s):  
Zhixiang Wang
Keyword(s):  
Cell Cycle ◽  
Growth Factor ◽  
Signaling Pathways ◽  
Tyrosine Kinases ◽  
Cell Cycle Progression ◽  
Phase Cell ◽  
Growth Factor Signaling ◽  
Cycle Progression ◽  
M Phase

The cell cycle is the series of events that take place in a cell, which drives it to divide and produce two new daughter cells. The typical cell cycle in eukaryotes is composed of the following phases: G1, S, G2, and M phase. Cell cycle progression is mediated by cyclin-dependent kinases (Cdks) and their regulatory cyclin subunits. However, the driving force of cell cycle progression is growth factor-initiated signaling pathways that control the activity of various Cdk–cyclin complexes. While the mechanism underlying the role of growth factor signaling in G1 phase of cell cycle progression has been largely revealed due to early extensive research, little is known regarding the function and mechanism of growth factor signaling in regulating other phases of the cell cycle, including S, G2, and M phase. In this review, we briefly discuss the process of cell cycle progression through various phases, and we focus on the role of signaling pathways activated by growth factors and their receptor (mostly receptor tyrosine kinases) in regulating cell cycle progression through various phases.

scholarly journals HIV-1 Vif promotes the G1- to S-phase cell-cycle transition

Blood ◽  
2011 ◽  
Vol 117 (4) ◽  
pp. 1260-1269 ◽  
Author(s):  
Jiangfang Wang ◽  
Emma L. Reuschel ◽  
Jason M. Shackelford ◽  
Lauren Jeang ◽  
Debra K. Shivers ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
S Phase ◽  
Phase Cell ◽  
Small Interfering Rnas ◽  
Cycle Progression ◽  
Viral Infectivity Factor ◽  
G2 Phase ◽  
Regulate Cell Cycle Progression ◽  
Hiv 1

AbstractHIV-1 depends on host-cell resources for replication, access to which may be limited to a particular phase of the cell cycle. The HIV-encoded proteins Vpr (viral protein R) and Vif (viral infectivity factor) arrest cells in the G2 phase; however, alteration of other cell-cycle phases has not been reported. We show that Vif drives cells out of G1 and into the S phase. The effect of Vif on the G1-to-S transition is distinct from its effect on G2, because G2 arrest is Cullin5-dependent, whereas the G1-to-S progression is Cullin5-independent. Using mass spectrometry, we identified 2 novel cellular partners of Vif, Brd4 and Cdk9, both of which are known to regulate cell-cycle progression. We confirmed the interaction of Vif and Cdk9 by immunoprecipitation and Western blot, and showed that small interfering RNAs (siRNAs) specific for Cdk9 inhibit the Vif-mediated G1-to-S transition. These data suggest that Vif regulates early cell-cycle progression, with implications for infection and latency.

Cell cycle control

2016 ◽  
pp. 31-41
Author(s):  
Simon M. Carr ◽  
Nicholas B. La Thangue
Keyword(s):  
Cell Cycle ◽  
Final Stage ◽  
Cell Cycle Progression ◽  
Cell Cycle Control ◽  
Control Mechanisms ◽  
Chromosomal Dna ◽  
Cycle Progression ◽  
M Phase ◽  
Cellular Components ◽  
Regulate Cell Cycle Progression

All cells arise by the division of existing cells in a highly regulated series of events known as the cell cycle. Whilst duplication of other cellular contents occurs throughout all stages of the cycle, chromosomal DNA is replicated only once at a stage known as S phase. Once this is complete, distribution of chromosomes and other cellular components occurs during the final stage of the cell cycle, known as M phase, or mitosis. The cell cycle is therefore regulated in a temporal fashion, so that entry into subsequent cell cycle stages only occurs once the previous stage has been completed. A number of signalling mechanisms monitor the integrity of cell cycle progression, and later cell cycle stages can be delayed if any errors need correction. This chapter gives an overview of the major control mechanisms that regulate cell cycle progression, and how these are circumvented during the onset of cancer.

Growth retardation and dyslymphopoiesis accompanied by G2/M arrest in APEX2-null mice

Blood ◽  
2004 ◽  
Vol 104 (13) ◽  
pp. 4097-4103 ◽  
Author(s):  
Yasuhito Ide ◽  
Daisuke Tsuchimoto ◽  
Yohei Tominaga ◽  
Manabu Nakashima ◽  
Takeshi Watanabe ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Proliferating Cell Nuclear Antigen ◽  
Cell Cycle Progression ◽  
Immunoglobulin M ◽  
Nuclear Antigen ◽  
Wild Type ◽  
Cycle Progression ◽  
Class Switch ◽  
M Phase ◽  
Proliferating Cell

Abstract APEX2/APE2 is a secondary mammalian apurinic/apyrimidinic endonuclease that associates with proliferating cell nuclear antigen (PCNA), and the progression of S phase of the cell cycle is accompanied by its expression. To determine the biologic significance of APEX2, we established APEX2-null mice. These mice were about 80% the size of their wild-type littermates and exhibited a moderate dyshematopoiesis and a relatively severe defect in lymphopoiesis. A significant accumulation of both thymocytes and mitogen-stimulated splenocytes in G2/M phase was seen in APEX2-null mice compared with the wild type, indicating that APEX2 is required for proper cell cycle progression of proliferating lymphocytes. Although APEX2-null mice exhibited an attenuated immune response against ovalbumin in comparison with wild-type mice, they produced both antiovalbumin immunoglobulin M (IgM) and IgG, indicating that class switch recombination can occur even in the absence of APEX2. (Blood. 2004;104: 4097-4103)

scholarly journals Influenza A Virus Replication Induces Cell Cycle Arrest in G0/G1 Phase

2010 ◽  
Vol 84 (24) ◽  
pp. 12832-12840 ◽  
Author(s):  
Yuan He ◽  
Ke Xu ◽  
Bjoern Keiner ◽  
Jianfang Zhou ◽  
Volker Czudai ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Influenza A Virus ◽  
Influenza A ◽  
Cell Cycle Progression ◽  
Virus Production ◽  
Phase Cell ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Infected Cells

ABSTRACT Many viruses interact with the host cell division cycle to favor their own growth. In this study, we examined the ability of influenza A virus to manipulate cell cycle progression. Our results show that influenza A virus A/WSN/33 (H1N1) replication results in G0/G1-phase accumulation of infected cells and that this accumulation is caused by the prevention of cell cycle entry from G0/G1 phase into S phase. Consistent with the G0/G1-phase accumulation, the amount of hyperphosphorylated retinoblastoma protein, a necessary active form for cell cycle progression through late G1 into S phase, decreased after infection with A/WSN/33 (H1N1) virus. In addition, other key molecules in the regulation of the cell cycle, such as p21, cyclin E, and cyclin D1, were also changed and showed a pattern of G0/G1-phase cell cycle arrest. It is interesting that increased viral protein expression and progeny virus production in cells synchronized in the G0/G1 phase were observed compared to those in either unsynchronized cells or cells synchronized in the G2/M phase. G0/G1-phase cell cycle arrest is likely a common strategy, since the effect was also observed in other strains, such as H3N2, H9N2, PR8 H1N1, and pandemic swine H1N1 viruses. These findings, in all, suggest that influenza A virus may provide favorable conditions for viral protein accumulation and virus production by inducing a G0/G1-phase cell cycle arrest in infected cells.

scholarly journals Cdk1-Mediated Phosphorylation of Human ATF7 at Thr-51 and Thr-53 Promotes Cell-Cycle Progression into M Phase

PLoS ONE ◽  
2014 ◽  
Vol 9 (12) ◽  
pp. e116048 ◽  
Author(s):  
Hitomi Hasegawa ◽  
Kenichi Ishibashi ◽  
Shoichi Kubota ◽  
Chihiro Yamaguchi ◽  
Ryuzaburo Yuki ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
M Phase

scholarly journals Loss of MCU prevents mitochondrial fusion in G1-S phase and blocks cell cycle progression and proliferation

2019 ◽  
Vol 12 (579) ◽  
pp. eaav1439 ◽  
Author(s):  
Olha M. Koval ◽  
Emily K. Nguyen ◽  
Velarchana Santhana ◽  
Trevor P. Fidler ◽  
Sara C. Sebag ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Cycle Progression ◽  
Mitochondrial Fission ◽  
Mitochondrial Fusion ◽  
Cycle Phase ◽  
Wild Type ◽  
Mitochondrial Fragmentation ◽  
Cycle Progression ◽  
Regulatory Circuit

The role of the mitochondrial Ca2+uniporter (MCU) in physiologic cell proliferation remains to be defined. Here, we demonstrated that the MCU was required to match mitochondrial function to metabolic demands during the cell cycle. During the G1-S transition (the cycle phase with the highest mitochondrial ATP output), mitochondrial fusion, oxygen consumption, and Ca2+uptake increased in wild-type cells but not in cells lacking MCU. In proliferating wild-type control cells, the addition of the growth factors promoted the activation of the Ca2+/calmodulin-dependent kinase II (CaMKII) and the phosphorylation of the mitochondrial fission factor Drp1 at Ser616. The lack of the MCU was associated with baseline activation of CaMKII, mitochondrial fragmentation due to increased Drp1 phosphorylation, and impaired mitochondrial respiration and glycolysis. The mitochondrial fission/fusion ratio and proliferation in MCU-deficient cells recovered after MCU restoration or inhibition of mitochondrial fragmentation or of CaMKII in the cytosol. Our data highlight a key function for the MCU in mitochondrial adaptation to the metabolic demands during cell cycle progression. Cytosolic CaMKII and the MCU participate in a regulatory circuit, whereby mitochondrial Ca2+uptake affects cell proliferation through Drp1.

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