| Modification Notes |
SSTRs (for somatostatin receptors) represent a family of G-protein-coupled receptors which mediate the diverse biological actions of somatostatin (SST) (1). There are five distinct subtypes of SSTRs that bind two natural ligands, SST-14 and SST-28 (1). SSTR2 gives rise to spliced variants, SSTR2A and 2B (1). SSTRs share common signaling pathways such as the ability to inhibit adenylyl cyclase via GTP binding proteins (1-3). Some of the subtypes are also coupled to tyrosine phosphatase (SSTR1,2), Ca2+ channels (SSTR2), Na+/H+ exchanger (SSTR1), PLA-2 (SSTR4), and MAP kinase (SSTR4) (1). Individual target cells typically express more than one SSTR subtype and often all five isoforms (4,5). Subtypes of SSTR can form functional homo- and heterodimers (6,7). |