Berlin 2012 – scientific programme

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BP: Fachverband Biologische Physik

BP 2: Physics of Cells I

BP 2.10: Talk

Monday, March 26, 2012, 12:15–12:30, H 1028

Probing PI3-kinase based cell reorientation in spatio-temporally controlled chemotactic gradient fields — Boern Meier and •Doris Heinrich — Center for Nanoscience (CeNS) and Faculty of Physics, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539 München

We developed a microfluidic chamber to manipulate cell migration in spatio-temporally controlled gradient fields. Bidirectional chemical gradients over a width of more than 300 um and timescales from seconds to several hours allow for parallel exposure of entire cell ensembles. This setup greatly facilitates statistical analysis of cellular migration properties in response to changing gradient directions and for genetic or pharmacological perturbation of the underlying regulatory network.

The long standing observation that actin polymerization, actuated by the phosphorylation of PIP2 by PI3-kinase, is primarily mediating chemotactic migration, has recently been challenged by the observation of Phospholipase A2 induced pseudopod splitting at the leading edge, which enhances persistence in directed cell migration. In Dictyostelium discoideum cells, we find that PI3-kinase based formation of new pseudopods is promoted by steep chemotactic gradients and reduced cellular starvation times, while reduction of the gradient steepness and ongoing starvation enhances persistent cell migration. Consecutive experiments with increased gradient switching frequencies promise further insight into the dynamic regulation of both parallel feedback loops.