FIGURE 4.

Peptides derived from the helix-turn-helix of PLC-β3 inhibit the capacity of Gα_q to activate p63RhoGEF. RhoA (100 nm) preloaded with BODIPY-GDP was incubated with unlabeled GDP (2 μm), Gα_q (100 nm), aluminum fluoride, and the indicated amounts of 27-mer(I860A) prior to measuring nucleotide exchange using fluorescence (cps, counts per second). p63RhoGEF (100 nm) was added as indicated. The trace marked RhoA only contains no Gα_q or p63RhoGEF and indicates spontaneous nucleotide exchange.