Twophoton imaging of insulin exocytosis in pancre

Authors: Noriko Takahashi

Publish Date: 2011/09/30

Volume: 2, Issue: 3, Pages: 112-121

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Abstract

The development of technologies for live optical imaging of exocytosis has improved the understanding of secretion We investigated the insulin exocytotic mechanism with twophoton imaging methods in intact pancreatic islets These studies revealed that high glucose levels induce two phases of insulin secretion and that this release is dependent upon cytosolic calcium Ca2+ This technology has also made it possible to examine the spatial distribution of insulin exocytosis in the islets and dynamics of the fusion pore Opening of the aqueous fusion pore was preceded by unrestricted lateral diffusion of a lipidic tracer along the inner wall of the pore indicating that the fusion pore is comprised mostly of membrane lipids By comparison with the other secretory glands the characteristic inhibition of compound exocytosis was also shown in the islet As the twophoton microscope enables simultaneous multicolor imaging the conformational states of proteins involved in membrane fusion can be analyzed during exocytosis These imaging studies have also helped to clarify regulatory mechanism of insulin exocytosisI appreciate Professor Takashi Kadowaki and Haruo Kasai for leading my research Hiroyuki Tamemoto Kazuki Yasuda Kohjiro Ueki Haruo Okado Yasuo Terauchi for molecular biology and islet study Tomomi Nemoto Takuya Kishimoto for biophysical experiments Hiroyasu Hatekayama Mitsuyo Ohno and all members in the laboratory for much work including FRET and SLMV expreriments This work was supported by the Funding Program for Next Generation WorldLeading Researchers NEXT Program of Japan Society for the Promotion of Science and the Global COE Program Integrative Life Science Based on the Study of Biosignaling Mechanisms of the Ministry of Education Culture Sports Science and Technology of Japan

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