On the ultrastructural organization of the microfilament system and the possible role of profilactin.

This paper summarizes results of studies on human glia cells concerning the ultrastructural relationships in the microfilament system and the possible role of the profilactin complex. It presents electron micrographs of the leading lamella of cells grown on solid substratum, visualizing the organization of the microfilament system in this highly motile part of the cell at high resolution and at what appears to be a high level of preservation. These results are linked to observations made in our laboratory of the biochemical basis for the dramatic rearrangements occurring in platelets in response to thrombin stimulation. Taken together these results lead to a relatively detailed model for the mechanism of cell motility.