Several studies in endothelial and epithelial cells have shown that wound repair and angiogenesis is often associated with altered connexin (Cx) expression and gap junctional communication. We analysed if Cx43 expression is involved in control of cell migration an integral part of wound repair processes. HeLa cells, which in the wild type do not express connexins and are unable to undergo cell-cell coupling, were stably transfected with a cDNA encoding Cx43. Migration of HeLa cells was studied in fluoroblok transwell chambers with 10% fetal calf serum as migration stimulus. Migration was significantly higher in cells expressing Cx43 as compared to wild type (wt) or empty vector-transfected (C) cells without Cx expression (augmentation of migration versus unstimulated cells after 8h: wt 1.370.1 n=5; Cx43 1.880.11; n=5 and C 1.260.15; n=2 independent cell cultures). Cell migration was also studied in a wound assay by time-lapse microscopy. Again, HeLa cells expressing Cx43 showed significantly increased migration distances (center of mass of all endpoints: +50%; accumulated distance: +40%; after 24h) compared to HeLa wt cells (n=4). To elucidate the mechanism of the increased migration of HeLa cells expressing Cx43, we analysed the role of cortactin in this context. The actin binding protein cortactin is a central element in the control of cell motility and involved in cytoskeleton remodelling and membrane dynamics. Since it has been shown in a recent publication that Cx43 can interact with cortactin, we performed coimmunoprecipitation experiments. Our data showed that full length Cx43 and a C-terminal part of Cx43 (AA 258–382) without channel function and which mediates the increased cell migration of Cx43 coimmunoprecipitated with cortactin (n=3). It is concluded, that Cx43 is important for cell migration and our results suggest that the interaction of Cx43 with cortactin which occurs specifically with the C-terminal part of Cx43, may play a role in the control of cell migration. Further analyses are necessary to clarify whether the association Cx43 with cortactin mediates the enhanced migration of Cx43 expressing HeLa cells.