FIGURE 6.

Alanine substitution in the C terminus of A chain alters the receptor-activation activity of RLN2. A, schematic representation of RLN2 mutants with alanine substitution at five different positions of the A chain (RLN2 T^A16A, RLN2 K^A17A, RLN2 R^A18A, RLN2^A19-20, and RLN2^A22-23). B, stimulation of cAMP production in LGR7- and LGR8-expressing cells by the wild type and mutant RLN2 peptides. Unlike the wild type peptide, RLN2 T^A16A and RLN2 K^A17A mutants exhibited a significantly enhanced LGR8-activation activity. C, competitive LGR7- and LGR8-binding assays of wild type and mutant RLN2 peptides. Each data point in the receptor-activation and receptor-binding assays represents the mean ± S.E. of quadruplicate and triplicate samples, respectively.