Fig. 5: Structural and functional presentation of subtype-selective site of SSTR2.

a Local sequence alignment of TM2, TM6, and TM7 of SSTR family. b Amino acid sites that may be associated with SSTR2 subtype selectivity are shown in the binding pockets of octreotide and lanreotide. c–e Ca²⁺ accumulation analysis of wild-type (WT) SSTR2 and mutants with octreotide. Site mutations to the corresponding amino acids of SSTR1 disrupted the receptor–ligand interactions, resulting in SSTR2 malfunction in the Ca²⁺ accumulation assay. Data are presented as means ± SEM of three independent experiments conducted in triplicate. f–h Ca²⁺ accumulation analysis of WT SSTR2 and mutants with lanreotide. Mutations to the corresponding amino acids of SSTR1 disrupted the receptor–ligand interactions, resulting in SSTR2 malfunction in the Ca²⁺ accumulation assay. Data are presented as means ± SEM of three independent experiments conducted in triplicate.