Table 2.

Comparison of integrated traction forces of FAK-null and FAK-expressing cells on soft and hard substrates

	Y* = 280 kdyn/cm2	Y = 150 kdyn/cm2
FAK-null	0.555  ± 0.158 (n = 18)	0.559  ± 0.197 (n = 18)
WT-FAK	0.661  ± 0.218 (n = 18)	0.514  ± 0.161 (n = 18)
F397-FAK	0.710  ± 0.194 (n = 12)	0.475  ± 0.193 (n = 12)

The total force output was computed by integrating the magnitude of traction stress over the cell area. Values are means ± SD, in dynes. Traction forces of cells expressing WT-FAK or F397-FAK on stiff substrates were significantly larger than those on soft substrates (P = 0.03 and 0.01, respectively). No statistically significant difference was found for FAK-null cells on different substrates (P = 0.95). 

^*Young's modulus.