Figure 1.

RhoG is activated after EGF stimulation but not by other growth factors or serum. Serum-starved cells were treated with the indicated growth factors or serum for 0, 2, and 5 min. Endogenous RhoG and Rac1 activities were measured from total cell lysates by pull-down assays by using GST-ELMO and GST-PBD, respectively. (A) HeLa cells were treated with 20% serum. Confirmation that Src and PI3K signaling occurred in responses to the serum treatment was done by blotting total cell lysates for Src-PY418 and Akt-PS473. (B) NIH-3T3 fibroblasts were treated with 20 ng/ml PDGF. (C) HUVECs were treated with 20 ng/ml VEGF. (D) HeLa cells were treated with EGF (20 ng/ml). Cellular responses in B, C, and D to stimulation by the specific growth factors were measured by blotting total cell lysates for phospho-tyrosine at the molecular weights corresponding to the relevant receptor tyrosine kinases.