“…These movements seem to be related to a membraneassociated microfilament system (14,27,28,36,38) that has frequently been shown to contain actin (2,22,24,29,30). Many morphological studies showing disruption of thin filament arrays (3,6,7,18,31,32,39,40) and a few studies with purified actin (16,21,33,34) or myosin (footnote 2 and reference 26) suggest that cytochalasins can interact directly with proteins of the microfilament system.…”