Several studies have shown that wound repair and angiogenesis is often associated with altered gap junctional communication (GJC) and connexin (Cx) expression. Since cell migration is part of this process we performed experiments to analyse the role of Cx expression in cell migration. HeLa wild type (wt) cells not expressing Cx were compared to HeLa cells constitutively expressing Cx37 or Cx43. The migration was significantly higher in Cx expressing HeLa cells after stimulation with FCS for 8h: fold migration (unstimulated cells = 1): wt 1.37±0.1; Cx43 1.88±0.11 and Cx37 1.84±0.15 (each n≥9 independent cell cultures). Western blot analysis revealed that the enhanced cell migration of HeLa-Cx37 and HeLa-Cx43 was associated with an increased activation of the p38 MAP kinase. To confirm this data endothelial progenitor cells (EPC) were used, which only express Cx43. Downregulation of Cx43 by siRNA resulted in decreased EPC cell migration after 24h: fold migration (unstimulated cells = 1): EPC-Control-siRNA: 4.57 ± 0.89 and EPC-Cx43-siRNA 1.66 ± 0.12 (n=2). These results suggest that Cx expression enhances cell migration via activation of p38 MAPK. Further analyses are necessary to clarify whether increased migration and p38 activation is due to Cx mediated (hemi)channel function or due to a function of Cx as an adapter molecule.