SSR2 Gene - Somatostatin Receptor 2: Function, Expression, and Clinical Significance

SSR2 (somatostatin receptor 2) is a gene encoding a G protein-coupled receptor for somatostatin, a peptide hormone that inhibits the release of growth hormone, insulin, glucagon, and other hormones. SSR2 is widely expressed in neuroendocrine tissues and is a primary target for somatostatin analogs used in the treatment of neuroendocrine tumors and acromegaly. The receptor mediates inhibitory effects on cell proliferation and hormone secretion through Gi/o protein signaling pathways.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• Somatostatin receptor signaling (Reactome: R-HSA-418594)

• GPCR downstream signaling (Reactome: R-HSA-388396)

• Class A/1 (Rhodopsin-like) receptors (Reactome: R-HSA-373076)

Somatostatin receptor 2 (SSR2) is a 369-amino acid integral membrane protein with seven transmembrane domains, belonging to the rhodopsin-like GPCR family. It binds somatostatin-14 and somatostatin-28 with high affinity, leading to activation of Gi/o proteins, inhibition of adenylyl cyclase, reduction of cAMP levels, and modulation of ion channels. SSR2 is the primary mediator of somatostatin's antisecretory and antiproliferative effects in neuroendocrine tissues. Clinically, it is exploited for imaging (e.g., 68Ga-DOTATATE PET) and therapy (e.g., 177Lu-DOTATATE PRRT) of somatostatin receptor-positive tumors.