FIG. 4.
Characterization of the interaction between Socius and Rnd GTPases. (A) COS-7 cells were transiently transfected with an expression vector encoding HA-tagged Rnd3, and cell lysates were incubated with GST (lane 2) or various GST-Socius fusion proteins (FL, full-length, amino acids 2 to 485, lane 3; NT, amino acids 2 to 238, lane 4; CT*, amino acids 186 to 485, lane 5; CT, amino acids 275 to 485, lane 6). Then they were immobilized on glutathione-Sepharose beads, and bound proteins and lysate input (Lysate, lane 1) were analyzed by immunoblotting with anti-HA monoclonal antibody (top). Coomassie brilliant blue staining of various GST fusion proteins used in this experiment was also shown (bottom, indicated by arrowheads). (B) COS-7 cells were transiently transfected with an expression vector encoding HA-tagged wild-type Rnd1 (WT, lanes 1 and 2), HA-tagged Rnd1N27 (N27, lane 3), or HA-tagged Rnd1A45 (A45, lane 4), and cell lysates were incubated with GST (lane 1) or GST-fused Socius CT (lanes 2 to 4). Then they were immobilized on glutathione-Sepharose beads, and bound proteins were analyzed by immunoblotting with anti-HA monoclonal antibody (top). Expression of Rnd1 proteins in cell lysates are also shown (bottom).