Movie S1.

Dictyostelium chemotaxis in response to the chemoattractant cAMP. The Dictyostelium cell responds to changes in spatial information (the location of the micropipette) by extending pseudopodia and migrating in the direction of the chemoattractant source. Movie provided courtesy of Susan Lee and Richard Firtel, Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA.