Insulin exocytotic mechanism by imaging technique.
Insulin is stored in pancreatic beta cell granules, and released biphasically by the exocytotic mechanism induced by nutrient glucose. Insulin exocytosis must be critically regulated to finely control body glucose homeostasis because insulin is the only hormone that can promptly reduce the blood glucose level. Recent advanced techniques in molecular biology and electrophysiology revealed the molecular mechanism of insulin release in the process from glucose entry to increased [Ca(2+)](i). However, the insulin exocytotic process such as translocation, docking and fusion of insulin granules was largely unknown. In order to reveal the molecular mechanism of this process, we utilized a newly innovated imaging technique, TIRF imaging system. Here we review recent results of our studies into docking and fusion of insulin granules analyzed by TIRF system.
Ohara-Imaizumi
Mica
M
Department of Biochemistry, Kyorin University School of Medicine, Mitaka, Tokyo 181-8611, USA. mimaizu@kyorin-u.ac.jp
Nagamatsu
Shinya
S
D000818:Animals; D005089:Exocytosis / Q000502:physiology*; D005947:Glucose / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence / Q000379:methods; D008954:Models, Biological
D007328:Insulin; D005947:Glucose