ADHESION-DEPENDENT F-ACTIN PATTERN IN AMOEBA PROTEUS AS A COMMON FEATURE OF AMOEBAE AND THE METAZOAN MOTILE CELLS.

Adhesion and movement of Amoeba proteus are both dependent on the appropriate arrangement of the F-actin cytoskeleton and on the presence of the cell nucleus. In this study the F-actin organization was examined by routine FITC-phalloidin staining and confocal laser microscopy in intact amoebae and in their nucleated and anucleated fragments, at different levels of cell adherence to the substratum. In the adhering and migrating intact cells and nucleated cell fragments dot-like aggregates of F-actin are scattered over the ventral side at sites close to the substratum.

Differences in the motility of Amoeba proteus isolated fragments are determined by F-actin arrangement and cell nucleus presence.

Isolated fragments produced by bisection of Amoeba proteus differ by their position in the original cell and by the presence or absence of the cell nucleus. Immediately after the operation, both types of anterior fragments preserve the former motory polarity, and do not interrupt locomotion. In the same time, all posterior fragments stop, round up and fail to react stimuli.