Intracellular trafficking of somatostatin receptors

The somatostatin receptor subtypes 1–5 (sst1–sst5) exhibit different intracellular trafficking and endosomal sorting after agonist exposure. The internalization of the somatostatin receptor subtypes sst2, sst3 and sst5 occurs to a much higher extent after somatostatin exposure than of sst1 or sst4. After endocytosis, sst2 and sst5 recycle to the plasma membrane, whereas sst3 is predominantly down-regulated. This review will focus on the molecular mechanisms of the differential intracellular trafficking of sst2, sst3 and sst5, and discusses our current knowledge on somatostatin receptor interacting proteins.