Internalization-defective mutants of somatostatin receptor subtype 2 exertnormal signaling functions in hematopoietic cells

The regulatory peptide somatostatin (SST) acts via a family of G-protein-co upled receptors comprising five subtypes (SSTR1-5). G-protein-coupled recep tors activate multiple signaling mechanisms, which variably depend on inter nalization and intracellular routing of activated receptors. We have recent ly demonstrated that hematopoietic precursors express SSTR2 and that SST is a chemoattractant for these cells. Herein, we characterize critical region s in SSTR2 involved in endocytosis and describe how ligand-induced internal ization impacts on two major signaling functions of SSTR2 in hematopoietic cells, the activation of the Erk pathway and the induction of promigratory responses. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.