Fig. 1.

Alternaria promotes recruitment of β-arrestins to protease-activated receptor-2 (PAR₂). A and B: bioluminescence resonance energy transfer (BRET) was measured upon addition of increasing concentrations of Alternaria (Alt) filtrate (A) or trypsin control (B). C: the time to reach maximal BRET signal was determined in response to Alt or trypsin. D: half-maximal (BRET₅₀) and maximal BRET values (BRET_max) were determined for recruitment of β-arrestin-2 to PAR₂ in response to 65 μg/ml Alt or 2 U/ml of trypsin. Alt triggered β-arrestin recruitment, similar to trypsin controls, albeit with a slightly reduced time constant; n ≥ 3 for all experimental time points; see materials and methods for experimental details.