MOTILITY OF VINCULIN-DEFICIENT F9 EMBRYONIC CARCINOMA-CELLS ANALYZED BY VIDEO, LASER CONFOCAL, AND REFLECTION INTERFERENCE CONTRAST MICROSCOPY

We have studied the motility of wild-type F9 and vinculin-deficient (5 .51) mouse embryonal carcinoma cells. F9 cells extended filopodia at a rate of 61 (+/- 18) nm/s over a distance of 3.18 (+/- 0.29) mu m. In contrast, 5.51 cells exhibited filopodia which extended at a similar s peed of 57 (+/- 17) nm/s but over a longer distance of 5.10 (+/- 2.14) mu m. Cell-substratum contact areas of both cell types were examined by reflection interference contrast microscopy. Wild-type F9 cells had distinct close contacts (dark gray areas) at the cell periphery, wher eas 5.51 cells had only a few light gray pinpoint contacts with the su bstrate. Confocal microscopy showed alpha-actinin to be localized alon g actin stress fibers in wild-type cells, and in 5.51 cells stress fib ers were absent and alpha-actinin was associated with F-actin in the f ilopodia. beta(1)-integrin, talin, and paxillin were concentrated in f ocal contacts in wild-type cells, but in 5.51 cells beta(1)-integrin a nd talin were in patches under the plasma membrane and paxillin was di ffusely distributed in the cytoplasm. We conclude that changes in cell shape and motility of 5.51 compared to wild-type F9 cells are due to the absence of vinculin even though there may be functions of other fo cal adhesion complex proteins, e.g., talin, linking the actin cytoskel eton to the plasma membrane. (C) 1995 Academic Press, Inc.