Bulletin of the American Physical Society
APS March Meeting 2014
Volume 59, Number 1
Monday–Friday, March 3–7, 2014; Denver, Colorado
Session Y12: Invited Session: Novel Modeling Approaches to Cell Motility |
Hide Abstracts |
Sponsoring Units: DCMP GSNP Chair: Lev Tsimring, University of California, San Diego Room: 205 |
Friday, March 7, 2014 8:00AM - 8:36AM |
Y12.00001: Coupling actin flow, adhesion, and morphology in a computational cell motility model Invited Speaker: Herbert Levine Eukaryotic cells crawl by means of the coordinated spatiotemporal dynamics of an active polymer gel, consisting of actin, myosin and regulators thereof. Motility is necessarily coupled to shape, as the force generating mechanisms such as polymerization-based protrusions interact with the elasticity of the cell membrane and thereby determine the cell morphology. We have introduced a ``phase-field'' model of crawling cells, utilizing a mathematical approach originally developed for morphology problems arising in the field of liquid-solid phase transitions. Our model can be used to explain the pattern of traction forces applied to the substrate as well as some recent observations concerning oscillatory instabilities of cells moving on one-dimensional fiber tracks. [Preview Abstract] |
Friday, March 7, 2014 8:36AM - 9:12AM |
Y12.00002: Modeling crawling cell movement on soft engineered substrates Invited Speaker: Igor Aronson Self-propelled motion, emerging spontaneously or in response to external cues, is a hallmark of living organisms. Systems of self-propelled synthetic particles are also relevant for multiple applications, from targeted drug delivery to the design of self-healing materials. Self-propulsion relies on the force transfer to the surrounding. While self-propelled swimming in the bulk of liquids is fairly well characterized, many open questions remain in our understanding of self-propelled motion along substrates, such as in the case of crawling cells or related biomimetic objects. How is the force transfer organized and how does it interplay with the deformability of the moving object and the substrate? How do the spatially dependent traction distribution and adhesion dynamics give rise to complex cell behavior? How can we engineer a specific cell response on synthetic compliant substrates? Here we present a phase-field model for a crawling cell by incorporating locally resolved traction forces and substrate deformations. The model captures the generic structure of the traction force distribution and faithfully reproduces experimental observations, like the response of a cell on a gradient in substrate elasticity (durotaxis). It also exhibits complex modes of cell movement such as ``bipedal'' motion. Our work may guide experiments on cell traction force microscopy and substrate-based cell sorting and can be helpful for the design of biomimetic ``crawlers'' and active and reconfigurable self-healing materials. [Preview Abstract] |
Friday, March 7, 2014 9:12AM - 9:48AM |
Y12.00003: Cell Motility Resulting form Spontaneous Polymerization Waves Invited Speaker: Karsten Kruse The crawling of living cells on solid substrates is often driven by the actin cytoskeleton, a network of structurally polar filamentous proteins that is intrinsically driven by the hydrolysis of ATP. How cells organize their actin network during crawling is still poorly understood. A possible general mechanism underlying actin organization has been offered by the observation of spontaneous actin polymerization waves in various different cell types. We use a theoretical approach to investigate the possible role of spontaneous actin waves on cell crawling. To this end, we develop a meanfield framework for studying spatiotemporal aspects of actin assembly dynamics, which helped to identify possible origins of self-organized actin waves. The impact of these waves on cell crawling is then investigated by using a phase-field approach to confine the actin network to a cellular domain. We find that spontaneous actin waves can lead to directional or amoeboidal crawling. In the latter case, the cell performs a random walk. Within our deterministic framework, this behavior is due to complex spiral waves inside the cell. Finally, we compare the seemingly random motion of our model cells to the dynamics of cells of the human immune system. These cells patrol the body in search for infected cells and we discuss possible implications of our theory for the search process' efficiency. [Preview Abstract] |
Friday, March 7, 2014 9:48AM - 10:24AM |
Y12.00004: A modular view of directed cell migration Invited Speaker: Pablo Iglesias Chemotaxis, the directed migration of cells in response to external chemical gradients, involves the coordinated action of separable but interrelated processes: motility, gradient sensing, and polarization. We have previously argued that separate ``modules'' give rise to these processes individually. In this talk I will describe a computational model in which the different modules are implemented in terms of reaction-diffusion equations. The central module is an excitable network. This module links to an idling cytoskeletal oscillator. In the absence of chemical stimuli, the excitable network can generate the signals that give rise to random migration. The response to combinations of uniform stimuli and gradients is mediated by a local excitation, global inhibition (LEGI) module that biases the direction in which excitability is directed. A polarization module linked to the excitable network through the cytoskeleton allows unstimulated cells to move persistently and, for cells in gradients, to gradually acquire distinct sensitivity between front and back. Migration and the accompanying changes in cellular morphology are simulated using a mechanical model of the cell implemented in the level set framework. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700