How do cells polarize?

Camilla Voeltz, Eberhard Bodenschatz

Cornell University, LASSP

When cells with cell surface receptors homogeneously distributed along their membrane sense a chemoattractant gradient, they become chemotactic and they polarize: They extend lamellipodia, contract their cell bodies and move towards the gradient of the chemoattractant. The cell polarization of the initially homogeneous cell manifests both in the directed movement of the cell towards the higher gradient of the chemoattractant and in the intracellular response of signaling molecules.

Recent studies have identified a number of signaling molecules and/or pathways that play essential roles in the regulation of chemotaxis. The mechanisms, however, by which these signaling pathways impact on the various processes are less well understood.

In order to gain more information about the mechanisms of chemotaxis and cell polarization, we have built microfluidic systems which allow to study eukaryotic cells like neutrophils, fibroblasts and Dictyostelium Discoideum cells under tailored spatial and spatio-temporal chemical gradients. At the moment we optically investigate both the response of the Dictyostelium cells at the cell scale and the intracellular response of the dynamics of fluorescently marked cytosolic proteins (CRAC::GFP) to these tailored chemo-attractant signals.