Vinculin in focal cell-to-substrate attachments of spreading corneal epithelial cells
H. K. Soong
Vinculin is a specialized protein with a molecular weight of 130
kilodaltons that is localized to focal regions of cell-to-substrate
attachment. It is located precisely at the termini of actin-containing
intracytoplasmic stress fibers, which appear to insert into the inner
surface of the cell membrane via the vinculin junctions. By double-labeling
corneal epithelial cells in tissue culture simultaneously for vinculin and
actin, the intimate association of stress fibers and cell-to-substrate
adhesion foci was demonstrated. At the leading edge of the migrating
epithelial sheet, discrete vinculin patches were numerous in the direction
of cell movement, while vinculin was less polarized and often diffusely
distributed in the cytoplasm in the less motile cells toward the center of
the cell colony. This study shows that corneal epithelial cell migration
and spreading during wound healing is characterized by relatively firm
substrate attachments at the advancing edge, with the cells behind the edge
possibly being pulled forward via cytoskeletal contractile mechanisms.
