Ras-ERK and PI3K-Akt are two key signaling pathways that regulate mammalian cell cycle progression and completion. At the single cell level, clonally derived cells often display substantial cell-to-cell variability in cell division fate. Previous work showed that single-cell ERK dynamics have some predictive capacity for whether a cell enters S-phase, and very recent results suggest that, in cells that do divide, post-S-phase ERK activity can influence cell cycle progression of daughters. However, the extent to which single-cell ERK and Akt dynamics are predictive of cell division is not well understood. How does ERK and Akt activity contribute to cell cycle progression beyond S-phase? Are features of single cell ERK and Akt signaling dynamics informative and predictive of cell division decisions?
To answer these questions, we use live cell imaging to pair kinase dynamics and cell division fate. Understanding how ERK and Akt dynamics drive cell division at the single cell level requires a robust cell imaging and analysis pipeline. Using kinase translocation reporters, along with image analysis software, we established an automated imaging pipeline that quantifies ERK and Akt dynamics paired to cell division. Surprisingly, in the non-transformed model MCF10A cell line, we found that single-cell ERK and Akt activity dynamics provide some predictive insight of cell division, which suggests that accurate predictions of single-cell division likely require measurements of multiple factors in addition to ERK and Akt activities. In contrast to single-cell dynamics, we found that population median ERK and Akt activities are higher throughout the entire cell cycle in dividing cells, suggesting that elevated ERK and Akt activity beyond the S-phase interval contributes to cell cycle completion. Measurements of ERK and Akt activities in the same single cell shows that they are less correlated in dividing cells as compared to non-dividing cells. Since network reconstruction experiments show no crosstalk between ERK and Akt activities in this system, the differences in correlation likely arise from dividing cell-specific upstream factors such as greater intrinsic capacity to activate ERK or Akt and/or increased pathway-biased interpretation of stimuli.
Overall, these findings support roles for ERK and Akt throughout the cell cycle, where elevated ERK and Akt activity contribute to cell cycle completion and offer predictive insight into cell division decisions. From a network perspective, we found that ERK and Akt do not appreciably interact and that ERK and Akt exhibit different degrees of correlation across dividing and non-dividing cells. These findings form a basis to subsequently understand how transformation alters the ERK/Akt network and its control of cell cycle progression.
|Advisor:||Birtwistle, Marc Russel|
|Commitee:||Albeck, John, Maze, Ian, O'Connell, Matthew, Schlessinger, Avner, Sobie, Eric A.|
|School:||Icahn School of Medicine at Mount Sinai|
|Department:||Pharmacology and System Biology|
|School Location:||United States -- New York|
|Source:||DAI-B 82/7(E), Dissertation Abstracts International|
|Keywords:||Cell cycle, Cell division, Cell signaling, Cell tracking, ERK and Akt, Image analysis|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be