Figure. Concentration-dependent activation of LPAR4 by LPA. Reporter cells were transfected with either the expression plasmid for lyso­phos­pha­tidic acid receptor 4 (LPAR4) or the mock plasmid and treated with various concentrations of lyso­phos­pha­tidic acid (LPA). Data points shown are the mean ± SEM of an experiment performed in triplicate, and the curve is a fit to Hill equation with an EC50 of 2.1 µM.