Fig. 7. PMA-induced podosomes depend on Src kinase in HUVECs. (A) PP2 inhibits PMA- but not V12Cdc42-induced podosomes. HUVECs were pretreated or not with 10 µM PP2 for 1 hour and then activated or not by PMA for 1 hour in the presence of the inhibitor. Alternatively, HUVECs were transfected with the GFP-V12Cdc42 construct and treated with PP2. Cells were labelled for F-actin. Bars, 10 µm. (B) Cdc42 is required for v-Src-induced podosome formation in PAE cells. PAE cells were co-transfected with v-Src-encoding plasmid together with GFP or GFP-N17Cdc42 constructs. GFP-positive cells showing podosomes were counted. Error bars represent the mean ± s.d. of three independent experiments. (C) v-Src activates Cdc42. PAE cells were transfected using a GFP-encoding (control) or a v-Src-encoding plasmid. Active GTPases were affinity-precipitated with GST-RBD-rhotekin or GST-CRIB-PAK and analysed by western blot using relevant antibodies. v-Src expression was visualised by western blot with anti-avian-Src antibodies. For each point, a fraction of the lysate was run to monitor the amount of GTPase before precipitation. (D) The graph shows quantitation of bands from two independent experiments; error bars represent the mean ± s.d.