Alanine substitution at the PheA23 position alters the
receptor-interaction activities of RLN2. A, schematic
representation of RLN2 mutants with alanine substitution at the
ArgA22 or PheA23 positions. B, stimulation of
cAMP production in LGR7- and LGR8-expressing cells by RLN2 RA22A
and RLN2 FA23A mutants. FA23A mutation ablated
LGR8-activation activity. C, LGR7- and LGR8-binding activities of
RA22A and FA23A mutant peptides. FA23A
mutation significantly reduced LGR8-binding activity, but without an effect on
LGR7-binding activity. Each data point in the receptor-activation and
receptor-binding assays represents the mean ± S.E. of quadruplicate and
triplicate samples, respectively.