BACKGROUND: VRP (vascular Rab-GAP/TBC domain containing protein) is a recently discovered gene from antisense - display screening of angiogenesis- related genes. However, its function in vascular endothelial cells has not been elucidated yet. This study was performed to examine the effects of overexpression of VRP on the function of vascular endothelial cells. METHODS: VRP cDNA was cloned from polyA+ RNA from human microvascular endothelial cells, and inserted into a mammalian expression plasmid vector under the control of a CMV promotor. The constructed VRP expression vector was transfected into ECV304 cells. Then the proliferation, tube formation, and vascular endothelial growth factor (VEGF) secretion of the VRP-overexpressed cells were examined. RESULTS: The expression of VRP mRNA was about two-fold greater in the VRP-transfected cells than in the control ECV304 cells. There was, however, no significant difference in the proliferation, cord-like structure formation, and VEGF secretion between the two cell groups. CONCLUSION: These results demonstrate that VRP overexpression does not affect the proliferation, tube formation, or VEGF secretion of ECV304 cells. Further studies are needed to elucidate the functional role of VRP in endothelial cells.