Actin filaments in the terminal webs of secretory ameloblasts of rats.

Actin filaments decorated with heavy meromyosin in enamel-secreting ameloblasts of rat incisors were examined. Proximal and distal terminal webs contained actin filaments; some were arrayed in diverse directions to each other. Some were associated with coated and uncoated vesicles. These actin filaments may relate to the sideways movement of secreting ameloblasts, suggesting that the distal terminal web is an apparatus generating a force by which ameloblasts can slide over each other.