Fig. 5. Rap1 activation induced by cell adhesion. (A) MEF-hC3G cells were infected with MX-pie-Cre or MX-pie. After 48 h, cells were trypsinized, kept in suspension for 1 h and plated on dishes coated with collagen type I. Cells were lysed at the indicated times. After normalizing on the protein quantity, the level of GTP-Rap1 was analyzed by Bos’s method. (B) MEF-hC3G cells were infected with MX-pie or MX-pie-Cre, maintained for 48 h, trypsinized, kept in suspension for 1 h and plated on dishes pre-coated as noted at the top. After 1 h, we harvested cells and examined the levels of GTP-bound Rap1, Rap2 and R-Ras. For the detection of GTP-R-Ras, we used MEF-hC3G cells infected with MSCV-R-Ras retrovirus as described in Figure 3C.