Actin filaments in the ameloblast of the rat incisor.

The distribution of actin filaments in the inner enamel-secretory ameloblast of the rat incisor was examined by labelling with heavy meromyosin. Actin filaments were mainly located in the long axis of the cell beneath the cell membrane. They tended to be more numerous in Tomes' process than in the cell body. Some filaments were associated with microtubules, with other actin filaments, and coated vesicles. Possible relation of the actin filaments to cell motility, stabilization of some, and movement of other cellular components is discussed.