scholarly journals Single-cell intracellular pH measurements reveal cell-cycle linked pH dynamics

2021 ◽  
Author(s):  
Julia S Spear ◽  
Katharine A White
Keyword(s):  
Cell Cycle ◽  
Single Cell ◽  
Intracellular Ph ◽  
Cell Cycle Progression ◽  
Single Cells ◽  
Population Level ◽  
Growth Factor Signaling ◽  
Cycle Progression ◽  
Cell Behaviors ◽  
Sinusoidal Pattern

Transient changes in intracellular pH (pHi) have been shown to regulate normal cell behaviors like migration and cell-cycle progression, while dysregulated pHi dynamics are a hallmark of cancer. However, little is known about how pHi heterogeneity and dynamics influence population-level measurements or single-cell behaviors. Here, we present and characterize single-cell pHi heterogeneity distributions in both normal and cancer cells and measure dynamic pHi increases in single cells in response to growth factor signaling. Next, we measure pHi dynamics in single cells during cell cycle progression. We determined that single-cell pHi is significantly decreased at the G1/S boundary, increases from S phase to the G2/M transition, rapidly acidifies during mitosis, and recovers in daughter cells. This sinusoidal pattern of pHi dynamics was linked to cell cycle timing regardless of synchronization method. This work confirms prior work at the population level and reveals distinct advantages of single-cell pHi measurements in capturing pHi heterogeneity across a population and dynamics within single cells.

scholarly journals Predicting Individual Cell Division Events from Single-Cell ERK and Akt Dynamics

2021 ◽  
Author(s):  
Alan D Stern ◽  
Gregory R Smith ◽  
Luis C Santos ◽  
Deepraj Sarmah ◽  
Xiang Zhang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Single Cell ◽  
Cell Cycle Progression ◽  
Time Window ◽  
Single Cells ◽  
Machine Learning Algorithms ◽  
Cycle Progression ◽  
Restriction Point ◽  
Activity Dynamics

Predictive determinants of stochastic single-cell fates have been elusive, even for the well-studied mammalian cell cycle. What drives proliferation decisions of single cells at any given time? We monitored single-cell dynamics of the ERK and Akt pathways, critical cell cycle progression hubs and anti-cancer drug targets, and paired them to division events in the same single cells using the non-transformed MCF10A epithelial line. Following growth factor treatment, in cells that divide both ERK and Akt activities are significantly higher within the S-G2 time window (~8.5-40 hours). Such differences were much smaller in the pre-S-phase, restriction point window which is traditionally associated with ERK and Akt activity dependence, suggesting unappreciated roles for ERK and Akt in S through G2. Machine learning algorithms show that simple metrics of central tendency in this time window are most predictive for subsequent cell division; median ERK and Akt activities classify individual division events with an AUC=0.76. Surprisingly, ERK dynamics alone predict division in individual cells with an AUC=0.74, suggesting Akt activity dynamics contribute little to the decision driving cell division in this context. We also find that ERK and Akt activities are less correlated with each other in cells that divide. Network reconstruction experiments demonstrated that this correlation behavior was likely not due to crosstalk, as ERK and Akt do not interact in this context, in contrast to other transformed cell types. Overall, our findings support roles for ERK and Akt activity throughout the cell cycle as opposed to just before the restriction point, and suggest ERK activity dynamics are substantially more important than Akt activity dynamics for driving cell division in this non-transformed context. Single cell imaging along with machine learning algorithms provide a better basis to understand cell cycle progression on the single cell level.

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 RETRACTED ARTICLE: Increased survival and cell cycle progression pathways are required for EWS/FLI1-induced malignant transformation

2016 ◽  
Vol 7 (10) ◽  
pp. e2419-e2419 ◽  
Author(s):  
Tahereh Javaheri ◽  
Zahra Kazemi ◽  
Jan Pencik ◽  
Ha TT Pham ◽  
Maximilian Kauer ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Family Member ◽  
Cell Cycle Progression ◽  
Bone Development ◽  
Bone Cancer ◽  
Growth Factor Signaling ◽  
Cycle Progression ◽  
Bcl2 Family ◽  
Immunocompromised Mice ◽  
Bcl2 Family Member

Abstract Ewing sarcoma (ES) is the second most frequent childhood bone cancer driven by the EWS/FLI1 (EF) fusion protein. Genetically defined ES models are needed to understand how EF expression changes bone precursor cell differentiation, how ES arises and through which mechanisms of inhibition it can be targeted. We used mesenchymal Prx1-directed conditional EF expression in mice to study bone development and to establish a reliable sarcoma model. EF expression arrested early chondrocyte and osteoblast differentiation due to changed signaling pathways such as hedgehog, WNT or growth factor signaling. Mesenchymal stem cells (MSCs) expressing EF showed high self-renewal capacity and maintained an undifferentiated state despite high apoptosis. Blocking apoptosis through enforced BCL2 family member expression in MSCs promoted efficient and rapid sarcoma formation when transplanted to immunocompromised mice. Mechanistically, high BCL2 family member and CDK4, but low P53 and INK4A protein expression synergized in Ewing-like sarcoma development. Functionally, knockdown of Mcl1 or Cdk4 or their combined pharmacologic inhibition resulted in growth arrest and apoptosis in both established human ES cell lines and EF-transformed mouse MSCs. Combinatorial targeting of survival and cell cycle progression pathways could counteract this aggressive childhood cancer.

scholarly journals Ras links growth factor signaling to the cell cycle machinery via regulation of cyclin D1 and the Cdk inhibitor p27KIP1.

1997 ◽  
Vol 17 (7) ◽  
pp. 3850-3857 ◽  
Author(s):  
H Aktas ◽  
H Cai ◽  
G M Cooper
Keyword(s):  
Cell Cycle ◽  
Growth Factor ◽  
Cyclin D1 ◽  
Cell Cycle Progression ◽  
Constitutive Expression ◽  
Ras Signaling ◽  
Cdk Inhibitor ◽  
Growth Factor Signaling ◽  
Cycle Progression ◽  
Cell Cycle Machinery

Activation of growth factor receptors by ligand binding initiates a cascade of events leading to cell growth and division. Progression through the cell cycle is controlled by cyclin-dependent protein kinases (Cdks), but the mechanisms that link growth factor signaling to the cell cycle machinery have not been established. We report here that Ras proteins play a key role in integrating mitogenic signals with cell cycle progression through G1. Ras is required for cell cycle progression and activation of both Cdk2 and Cdk4 until approximately 2 h before the G1/S transition, corresponding to the restriction point. Analysis of Cdk-cyclin complexes indicates that Ras signaling is required both for induction of cyclin D1 and for downregulation of the Cdk inhibitor p27KIP1. Constitutive expression of cyclin D1 circumvents the requirement for Ras signaling in cell proliferation, indicating that regulation of cyclin D1 is a critical target of the Ras signaling cascade.

scholarly journals Characterizing and inferring quantitative cell cycle phase in single-cell RNA-seq data analysis

2019 ◽  
Author(s):  
Chiaowen Joyce Hsiao ◽  
PoYuan Tung ◽  
John D. Blischak ◽  
Jonathan E. Burnett ◽  
Kenneth A. Barr ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Single Cell ◽  
Cell Cycle Progression ◽  
Cell Types ◽  
Cell Cycle Phase ◽  
Cellular Heterogeneity ◽  
Cycle Phase ◽  
Cycle Progression ◽  
Cellular Environment

AbstractCellular heterogeneity in gene expression is driven by cellular processes such as cell cycle and cell-type identity, and cellular environment such as spatial location. The cell cycle, in particular, is thought to be a key driver of cell-to-cell heterogeneity in gene expression, even in otherwise homogeneous cell populations. Recent advances in single-cell RNA-sequencing (scRNA-seq) facilitate detailed characterization of gene expression heterogeneity, and can thus shed new light on the processes driving heterogeneity. Here, we combined fluorescence imaging with scRNA-seq to measure cell cycle phase and gene expression levels in human induced pluripotent stem cells (iPSCs). Using these data, we developed a novel approach to characterize cell cycle progression. While standard methods assign cells to discrete cell cycle stages, our method goes beyond this, and quantifies cell cycle progression on a continuum. We found that, on average, scRNA-seq data from only five genes predicted a cell’s position on the cell cycle continuum to within 14% of the entire cycle, and that using more genes did not improve this accuracy. Our data and predictor of cell cycle phase can directly help future studies to account for cell-cycle-related heterogeneity in iPSCs. Our results and methods also provide a foundation for future work to characterize the effects of the cell cycle on expression heterogeneity in other cell types.

scholarly journals Functional oscillation of a multienzyme glucosome assembly during cell cycle progression

2022 ◽  
Author(s):  
Miji Jeon ◽  
Danielle L Schmitt ◽  
Minjoung Kyoung ◽  
Songon An
Keyword(s):  
Cell Cycle ◽  
Glucose Metabolism ◽  
Single Cell ◽  
Cell Biology ◽  
Cell Cycle Progression ◽  
Metabolic Adaptation ◽  
Dependent Manner ◽  
Cycle Progression ◽  
Size Dependent ◽  
A Cell

Glucose metabolism has been studied extensively to understand functional interplays between metabolism and a cell cycle. However, our understanding of cell cycle-dependent metabolic adaptation particularly in human cells remains largely elusive. Meanwhile, human enzymes in glucose metabolism are shown to functionally organize into three different sizes of a multienzyme metabolic assembly, the glucosome, to regulate glucose flux in a size-dependent manner. Here, using fluorescence single-cell imaging techniques, we discover that glucosomes spatiotemporally oscillate during a cell cycle in an assembly size-dependent manner. Importantly, their oscillation at single-cell levels is in accordance with functional contributions of glucose metabolism to cell cycle progression at a population level. Collectively, we demonstrate functional oscillation of glucosomes during cell cycle progression and thus their biological significance to human cell biology.

scholarly journals Glycogen Synthase Kinase 3 Phosphorylates RBL2/p130 during Quiescence

2004 ◽  
Vol 24 (20) ◽  
pp. 8970-8980 ◽  
Author(s):  
Larisa Litovchick ◽  
Anton Chestukhin ◽  
James A. DeCaprio
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Growth Factor Signaling ◽  
Cycle Progression ◽  
Pocket Proteins ◽  
Cyclin Dependent Kinases ◽  
The Stability

ABSTRACT Phosphorylation of the retinoblastoma-related or pocket proteins RB1/pRb, RBL1/p107, and RBL2/p130 regulates cell cycle progression and exit. While all pocket proteins are phosphorylated by cyclin-dependent kinases (CDKs) during the G1/S-phase transition, p130 is also specifically phosphorylated in G0-arrested cells. We have previously identified several phosphorylated residues that match the consensus site for glycogen synthase kinase 3 (GSK3) in the G0 form of p130. Using small-molecule inhibitors of GSK3, site-specific mutants of p130, and phospho-specific antibodies, we demonstrate here that GSK3 phosphorylates p130 during G0. Phosphorylation of p130 by GSK3 contributes to the stability of p130 but does not affect its ability to interact with E2F4 or cyclins. Regulation of p130 by GSK3 provides a novel link between growth factor signaling and regulation of the cell cycle progression and exit.

scholarly journals Disentangling Pro-mitotic Signaling during Cell Cycle Progression using Time-Resolved Single-Cell Imaging

Cell Reports ◽  
2020 ◽  
Vol 31 (2) ◽  
pp. 107514 ◽  
Author(s):  
Manuela Benary ◽  
Stefan Bohn ◽  
Mareen Lüthen ◽  
Ilias K. Nolis ◽  
Nils Blüthgen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Single Cell ◽  
Cell Cycle Progression ◽  
Cell Imaging ◽  
Cycle Progression ◽  
Time Resolved ◽  
Single Cell Imaging
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