Figure 2.

Rap1 activates Rac1. HeLa cells were transfected with an empty vector or a vector encoding constitutively active HA-63E Rap1a. Cells were suspended, plated on fibronectin (FN) or poly-l-lysine (PLL) for 3 h, and lysed, and then active GTP-bound Rac1 was precipitated with GST-PBD PAK1. Precipitates (active) and total cell lysates (total) were then immunoblotted with Rac1 or HA antibodies.