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Dissertation/Thesis Abstract

Predicting Single Cell Division from ERK and Akt Dynamics
by Stern, Alan D., Ph.D., Icahn School of Medicine at Mount Sinai, 2021, 134; 28261552
Abstract (Summary)

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.

Indexing (document details)
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
Subjects: Cellular biology
Keywords: Cell cycle, Cell division, Cell signaling, Cell tracking, ERK and Akt, Image analysis
Publication Number: 28261552
ISBN: 9798557093866
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