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Liu et al. (Reports, March 23, 2007, p. 1712) reported that the Arabidopsis thaliana gene GCR2 encodes a seven-transmembrane, G protein–coupled receptor for abscisic acid. We argue that GCR2 is not likely to be a transmembrane protein nor a G protein–coupled receptor. Instead, GCR2 is most likely a plant homolog of bacterial lanthionine synthetases.