In our experiments, RGS2 inhibited PAR4-induced downstream signaling events, including ERK phosphorylation, calcium mobilization, RhoA activity, and cancer progression-related gene expression, suggesting that RGS2 forms a ternary complex with PAR4 and Gαq, PAR4-RGS2-Gαq, that acts to inhibit PAR4/Gαq signaling. Here, GNAQ is linked to cancer.