| Background: Cell adhesion and spreading on matrix substrates are fundamental processes contributing to periodontal wound healing. p21-activated kinases (PAKs) are involved in regulating cell spreading, the mechanism for which remains undefined. Objective: Examine the role of PAK-1 in collagen remodeling by cell extension formation. Methods: NIH-3T3 mouse fibroblasts were treated with control or PAK-1 siRNA. The number and length of cell extensions were measured in cells cultured on floating collagen matrices. Activated beta1 integrins and focal adhesions per cell were measured. Further, cell contraction and collagen remodeling were examined. Finally, cell contractile activity was estimated. Results: PAK-1 knockdown cells exhibited fewer and shorter cell membrane extensions, reduced cell area, and reduced activated beta1 integrin staining and focal adhesions per cell. PAK-1 knock-down cells showed reduced contraction and collagen fiber alignment. Conclusions: PAK-1 regulates cell adhesion to collagen by promoting the generation of cell extensions, which enhance tractional remodeling of collagen. |
