FIGURE 6. The conserved PH domain extension of p63RhoGEF is essential for direct binding of activated Gα_q.

A, analytical gel-exclusion chromatography was used to isolate a heterodimeric complex of AlF₄-activated Gα_q with GST-tagged p63RhoGEF (GST-DH-Ext); under identical conditions the GST-DH-PH construct did not complex with AlF₄-activated Gα_q (lower panel). B, GST-tagged p63RhoGEF truncation constructs (GSTDH- Ext and GST-DH-PH) were immobilized onto the surface of the Biacore chip; analyte consisting of 10 µm AlF₄-activated Gα_q was then flowed over each surface while measuring surface plasmon resonance. C, a fluorophore- conjugated peptide corresponding to the conserved PH domain extension of human p63RhoGEF (residues 467– 493) was used in a polarization/anisotropy-based assay to show direct dose-dependent binding to AlF₄-activated Gα_q.