Somatostatin type V receptor activates c-Jun N-terminal kinases via Galpha(12) family G proteins.

Somatostatin is a neurotransmitter with diverse effects including anti-proliferation in a wide range of normal and neoplastic cells, and occasionally growth stimulatory and neurotrophic actions. Stress-activated protein kinase or c-Jun N-terminal kinase (SAPK/JNK) can also induce growth arrest and occasionally growth stimulation. However, the relationship between somatostatin and SAPK/JNK is less clear. Here we report that the binding of somatostatin to the somatostatin receptor type V (SSTR5) upregulates SAPK/JNK activity. We also show that this activation is mediated by Galpha(12) and Galpha(13). This study demonstrates that SSTR5 is the heptahelical receptor that activates SAPK/JNK via the G(12) family G proteins.