title: Beta-Arrestin-1 mediates glucagon-like peptide-1 signaling to insulin secretion in cultured pancreatic beta cells.
abstract: Glucagon-like peptide-1 (GLP-1) is a polypeptide hormone secreted from enteroendocrine L cells and potentiates glucose-dependent insulin secretion in pancreatic beta cells. Recently the GLP-1 receptor (GLP-1 R) has been a focus for new anti-diabetic therapy with the introduction of GLP-1 analogues and DPP-IV inhibitors, and this has stimulated additional interest in the mechanisms of GLP-1 signaling. Here we identify a mechanism for GLP-1 action, showing that the scaffold protein beta-arrestin-1 mediates the effects of GLP-1 to stimulate cAMP production and insulin secretion in beta cells. Using a coimmunoprecipitation technique, we also found a physical association between the GLP-1 R and beta-arrestin-1 in cultured INS-1 pancreatic beta cells. beta-Arrestin-1 knockdown broadly attenuated GLP-1 signaling, causing decreased ERK and CREB activation and IRS-2 expression as well as reduced cAMP levels and impaired insulin secretion. However, beta-arrestin-1 knockdown did not affect GLP-1 R surface expression and ligand-induced GLP-1 R internalization/desensitization. Taken together, these studies indicate that beta-arrestin-1 plays a role in GLP-1 signaling leading to insulin secretion, defining a previously undescribed mechanism for GLP-1 action.
authors.affiliation: Department of Medicine, Division of Endocrinology and Metabolism, University of California at San Diego, La Jolla, CA 92093, USA.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Sonoda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Imamura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshizaki
authors.forename: Jennie L
authors.initials: JL
authors.lastname: Babendure
authors.forename: Juu-Chin
authors.initials: JC
authors.lastname: Lu
authors.forename: Jerrold M
authors.initials: JM
authors.lastname: Olefsky
mesh_terms: D000818:Animals; D019390:Arrestins / Q000378:metabolism*; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004705:Endocytosis / Q000187:drug effects; D052216:Glucagon-Like Peptide 1 / Q000494:pharmacology*; D000067757:Glucagon-Like Peptide-1 Receptor; D007328:Insulin / Q000378:metabolism*; D055504:Insulin Receptor Substrate Proteins; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D018027:Receptors, Glucagon / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D000071559:beta-Arrestin 1; D000071557:beta-Arrestins
chemical_list: C000605256:Arrb1 protein, rat; D019390:Arrestins; C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D047908:Intracellular Signaling Peptides and Proteins; C526299:Irs2 protein, rat; D010750:Phosphoproteins; D018027:Receptors, Glucagon; D000071559:beta-Arrestin 1; D000071557:beta-Arrestins; D052216:Glucagon-Like Peptide 1; D000242:Cyclic AMP