Bleb-driven chemotaxis ofDictyosteliumcells

An aggregation-competent Dictyostelium Ax2 cell expressing ABD-RFP (red) as a reporter for F-actin and cAR1-GFP (green) as a marker for the plasma membrane is observed on a glass coverslip under KK2 buffer. Two successive blebs form on the flank of the cell (time frames 131-132), leaving F-actin scars behind. F-actin rapidly polymerises (within 1 second) at the bleb membranes to reconstitute the cortex, but polymerization continues, transforming the blebs into a pseudopod. The movie was taken by DIC and laser-scanning confocal microscopy (LSM 710; Carl Zeiss).