Following the gradient sensing phase, cells reorganize their internal components into a symmetry-broken configuration, resulting in an elongated cell with a clearly identifiable back, front, and side. This polarized state is coupled to motility through the formation of membrane extensions, pseudopodia, which occur mostly at the front of the cell. Using quantitative measurements on cells that are vertically restricted, we have determined that these pseudopodia are closely correlated with membrane areas (""""""""patches"""""""") of increased concentration of activated Ras, Ras-GTP. What remains unclear, however, is the role Ras-GTP plays in restricting the pseudopodia to the front of the cell. Furthermore, the mechanisms for the transient nature of the patches and pseudopodia are unclear. Finally, there is a vigorous and ongoing debate whether new pseudopodia split off existing ones via a specialized fip-splitting mechanism or whether new pseudopodia are created in a stochastic fashion, largely independent of the location of the existing pseudopod. The goal of this project will be to examine the mechanisms of cell polarity using microfluidics technology in combination with modeling efforts. The quantitative results from the experiments will be used to construct mathematical models. Conversely, through specific predictions, these models will guide the experiments. Again, we think that such two-way communication between experiments and modeling is essential in making progress in understanding the role of polarity in chemotaxis.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Program Projects (P01)
Project #
5P01GM078586-08
Application #
8720783
Study Section
Special Emphasis Panel (ZRG1)
Project Start
Project End
Budget Start
2014-08-01
Budget End
2015-07-31
Support Year
8
Fiscal Year
2014
Total Cost
Indirect Cost
Name
University of California San Diego
Department
Type
DUNS #
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Yue, Haicen; Camley, Brian A; Rappel, Wouter-Jan (2018) Minimal Network Topologies for Signal Processing during Collective Cell Chemotaxis. Biophys J 114:2986-2999
Camley, Brian A (2018) Collective gradient sensing and chemotaxis: modeling and recent developments. J Phys Condens Matter 30:223001
Tu, Yuhai; Rappel, Wouter-Jan (2018) Adaptation of Living Systems. Annu Rev Condens Matter Phys 9:183-205
Camley, Brian A; Rappel, Wouter-Jan (2017) Physical models of collective cell motility: from cell to tissue. J Phys D Appl Phys 50:
Camley, Brian A; Rappel, Wouter-Jan (2017) Cell-to-cell variation sets a tissue-rheology-dependent bound on collective gradient sensing. Proc Natl Acad Sci U S A 114:E10074-E10082
Rappel, Wouter-Jan; Edelstein-Keshet, Leah (2017) Mechanisms of Cell Polarization. Curr Opin Syst Biol 3:43-53
Camley, Brian A; Zhao, Yanxiang; Li, Bo et al. (2017) Crawling and turning in a minimal reaction-diffusion cell motility model: Coupling cell shape and biochemistry. Phys Rev E 95:012401
Camley, Brian A; Zimmermann, Juliane; Levine, Herbert et al. (2016) Emergent Collective Chemotaxis without Single-Cell Gradient Sensing. Phys Rev Lett 116:098101
Zimmermann, Juliane; Camley, Brian A; Rappel, Wouter-Jan et al. (2016) Contact inhibition of locomotion determines cell-cell and cell-substrate forces in tissues. Proc Natl Acad Sci U S A 113:2660-5
Bastounis, Effie; Álvarez-González, Begoña; del Álamo, Juan C et al. (2016) Cooperative cell motility during tandem locomotion of amoeboid cells. Mol Biol Cell 27:1262-71

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