title: Imaging exocytosis of single glucagon-like peptide-1 containing granules in a murine enteroendocrine cell line with total internal reflection fluorescent microscopy.
abstract: To analyze the exocytosis of glucagon-like peptide-1 (GLP-1) granules, we imaged the motion of GLP-1 granules labeled with enhanced yellow fluorescent protein (Venus) fused to human growth hormone (hGH-Venus) in an enteroendocrine cell line, STC-1 cells, by total internal reflection fluorescent (TIRF) microscopy. We found glucose stimulation caused biphasic GLP-1 granule exocytosis: during the first phase, fusion events occurred from two types of granules (previously docked granules and newcomers), and thereafter continuous fusion was observed mostly from newcomers during the second phase. Closely similar to the insulin granule fusion from pancreatic beta cells, the regulated biphasic exocytosis from two types of granules may be a common mechanism in glucose-evoked hormone release from endocrine cells.
authors.affiliation: Department of Biochemistry, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, Japan.
authors.forename: Mica
authors.initials: M
authors.lastname: Ohara-Imaizumi
authors.forename: Kyota
authors.initials: K
authors.lastname: Aoyagi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Akimoto
authors.forename: Yoko
authors.initials: Y
authors.lastname: Nakamichi
authors.forename: Chiyono
authors.initials: C
authors.lastname: Nishiwaki
authors.forename: Hayato
authors.initials: H
authors.lastname: Kawakami
authors.forename: Shinya
authors.initials: S
authors.lastname: Nagamatsu
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D005089:Exocytosis; D052216:Glucagon-Like Peptide 1 / Q000737:chemistry / Q000378:metabolism*; D019382:Human Growth Hormone / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008164:Luminescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods; D022142:Secretory Vesicles / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008164:Luminescent Proteins; C054562:yellow fluorescent protein, Bacteria; D019382:Human Growth Hormone; D052216:Glucagon-Like Peptide 1