(137f) Spatiotemporal Analysis of Signaling and Motility During Fibroblast Migration: Mechanisms and Models of Directional Persistence

Cell migration requires coordination between intracellular signaling and extracellular cues to orchestrate the cellular processes necessary for efficient cell movement. However, the spatial heterogeneity and stochasticity of the cell signaling events that appear to drive cell migration make it difficult to analyze without using live-cell, spatially-resolved measurements of cell signaling activity. In this work, we use total internal reflection fluorescence (TIRF) microscopy to image membrane-localized signaling events continuously during cell migration and quantitative analysis to understand how these signaling events may be related. Specifically, we image the activity of phosphoinositide-3 kinase (PI3K) and Rac1 GTPase along with the localization of the focal adhesion scaffolding protein paxillin, all of which have been strongly implicated in coordination of migration signaling. We use purpose-built image analysis tools to identify regions of high signaling activity and to map their spatiotemporal profile in migrating cells. Parallel analysis of the cell's morphology and local protrusion rate during migration allows us to relate the spatiotemporal profiles of cell signaling events with cell morphology as a cell moves. Overall, this analysis provides insight into how cell signaling is influenced by cell morphology, and conversely how cell signaling may affect morphology and migration persistence by localizing cellular protrusion.