Large-scale Actin Wave Patterns Perturbed by Electric and Mechanical Cues in Giant Dictyostelium discoideum*

Dictyostelium discoideum(Dd) provides a good system to study actin dynamics guided by extracellular cues such as electric field, mechanical cues and chemical gradients. However, waves in normal Dd extinguish at the boundary and only show confined sections of wave patterns. Here we apply electrofusion to produce giant Dd, a polykaryotic cell which is up to ten times the size of normal Dd. In those cells F-actin waves travel freely across plasma membrane and show large-scale wave patterns independent of boundary effects. We use this system to explore how nanoridges and DC electric fields perturb actin waves on a scale as large as 50 microns.