title: Immunohistochemical analysis of IA-2 family of protein tyrosine phosphatases in rat gastrointestinal endocrine cells.
abstract: Islet-associated protein-2 (IA-2) and IA-2β (also known as phogrin) are unique neuroendocrine-specific protein tyrosine phosphatases (PTPs). The IA-2 family of PTPs was originally identified from insulinoma cells and discovered to be major autoantigens in type 1 diabetes. Despite its expression in the neural and canonical endocrine tissues, data on expression of the IA-2 family of PTPs in gastrointestinal endocrine cells (GECs) are limited. Therefore, we immunohistochemically investigated the expression of the IA-2 family of PTPs in the rat gastrointestinal tract. In the stomach, IA-2 and IA-2β were expressed in GECs that secrete serotonin, somatostatin, and cholecystokinin/gastrin-1. In addition to these hormones, secretin, gastric inhibitory polypeptide (also known as the glucose-dependent insulinotropic peptide), glucagon-like peptide-1, and glucagon, but not ghrelin were coexpressed with IA-2 or IA-2β in duodenal GECs. Pancreatic islet cells that secrete gut hormones expressed the IA-2 family of PTPs. The expression patterns of IA-2 and IA-2β were comparable. These results reveal that the IA-2 family of PTPs is expressed in a cell type-specific manner in rat GECs. The extensive expression of the IA-2 family of PTPs in pancreo-gastrointestinal endocrine cells and in the enteric plexus suggests their systemic contribution to nutritional control through a neuroendocrine signaling network.
authors.affiliation: Department of Veterinary Anatomy, College of Bioresource Sciences, Nihon University, Kanagawa, Japan. gomi.hiroshi@nihon-u.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Gomi
authors.forename: Chisato
authors.initials: C
authors.lastname: Kubota-Murata
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yasui
authors.forename: Azuma
authors.initials: A
authors.lastname: Tsukise
authors.forename: Seiji
authors.initials: S
authors.lastname: Torii
mesh_terms: D000818:Animals; D000906:Antibodies; D019858:Enteroendocrine Cells / Q000166:cytology*; D041981:Gastrointestinal Tract / Q000648:ultrastructure; D006728:Hormones / Q000032:analysis; D007150:Immunohistochemistry / Q000379:methods; D007515:Islets of Langerhans / Q000648:ultrastructure; D008297:Male; D010902:Pituitary Gland / Q000648:ultrastructure; D051381:Rats; D020318:Rats, Long-Evans; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8 / Q000032:analysis*
chemical_list: D000906:Antibodies; D006728:Hormones; C105576:Ptprn2 protein, rat; D054635:Receptor-Like Protein Tyrosine Phosphatases, Class 8