Fig. 1.

Identification of Cdc42 interaction partners with SILAC-qGAP. (A) Rho GTPases were expressed, purified, loaded with either GDP or GTPγS, and bound to a Sepharose matrix. Protein samples were obtained from SILAC-labeled cells. Proteins from H- and l-labeled cells were pulled down with Cdc42GTPγS and Cdc42GDP in a forward (arrows) and reverse experiment. Bound proteins were eluted and analyzed via mass spectrometry. Significant outliers were calculated (labeled in orange) for the forward (B) and reverse (C) experiment. Proteins that are significant outliers in the forward and reverse experiment and that were specific to one nucleotide form in both experiments are considered specific interaction partners of Cdc42 (D, labeled in orange).