Fig. 8.

Trypsin stimulates MAP kinase signaling in β-arrestin-null DKO MEF cells transfected with wt-rPAR₂ (A), rPAR₂-Leu³⁷Ser³⁸ (B), or rPAR₂-Ala^37–38 (C) MAP kinase activation, expressed as a -fold increase (P-p42/44) relative to total enzyme (T-p42/44), as monitored at timed intervals for receptors expressed in either wild-type fibroblasts (○, MEF wt) or β-arrestin-null fibroblasts (■, MEF DKO). Data points showing the average values for triplicate measurements (± S.E.M., bars) are representative of three independent experiments.