Cellular internalisation of uPA is equivalent between wild-type PAI-2 and PAI-2 ΔCD-loop as determined by flow cytometry. MCF-7 cells were incubated with 10 nM uPA:Alexa488, either alone or in complex with wild-type PAI-2 or PAI-2 ΔCD-loop for 1 h at 37°C. Any surface bound uPA:Alexa488 remaining was quenched by incubation with 4 μg/mL anti-Alexa488 polyclonal antibody for 30 min prior to analysis by dual colour flow cytometry. Values shown are means ± SEM (n = 3) as a percentage of uPA only treatment.*p < 0.005 compared to internalisation in the absence of RAP for each treatment.