| Abstract: | The role of fibronectin in the contraction of collagen lattices by human skin fibroblasts has been investigated. Incubation of lattice cultures in Dulbecco's modified Eagle's medium supplemented with increasing concentrations of non-dialysed or dialysed fetal calf serum demonstrated that the rate of contraction was dependent on non-dialysable serum components. The suppression of contraction observed when fibronectin was eliminated from serum, either by affinity chromatography on gelatin-agarose columns or by precipitation with anti-fibronectin antibodies, showed that fibronectin is critical for the contraction. When collagen lattices were incubated in a serum-free culture medium totally devoid of fibronectin, no contraction occurred. When fibronectin was added to this medium, their contraction was correlated with the concentration of fibronectin added. The contraction was inhibited by cycloheximide, tunicamycin, and monensin. These results demonstrate that the contraction of collagen lattices by human skin fibroblasts is dependent on fibronectin, and that other protein factors synthesized by the cells or contained in serum are also necessary. |
