Binding of vitronectin (VN) to Neisseria gonorrhoeae expressing the heparan sulfate proteoglycan (HSPG) specific Opa50 protein was recently shown to trigger bacterial internalization into distinct epithelial cell lines. We have investigated the role of VN-binding integrin receptors and protein kinase C (PKC) in VN-triggered bacterial uptake. Blocking integrin function by RGDS peptides or by antibodies specific to alpha(v)beta5 or alpha(v)beta3 resulted in an abrogation of VN-triggered bacterial internalization. Moreover, inhibitors of PKC were found to block VN-triggered uptake. The essential role of alpha(v) integrins and the presumable involvement of PKC in VN-triggered gonococcal uptake are discussed.