Syntaxin, but not soluble NSF attachment protein (SNAP), biosynthesis by rat pancreatic islets is regulated by glucose in parallel with proinsulin biosynthesis

Diabetologia
S NagamatsuH Katahira

Abstract

Recent studies have revealed that soluble N-ethylmaleimide sensitive factor attachment receptor (SNARE)-related proteins, originally identified in neural tissues, are also expressed in pancreatic beta cells. In this study, we investigated the effect of glucose on syntaxin 1 and alpha/beta SNAP biosynthesis in pancreatic beta cells and we demonstrated that syntaxin 1, but not alpha/beta SNAP biosynthesis by rat isolated pancreatic islets was stimulated specifically by glucose nearly in parallel with proinsulin biosynthesis. Stimulation of syntaxin 1 and proinsulin biosynthesis by glucose was dose-dependent (Km = approximately 8 mmol/l) and reached the maximum (about 8-12 fold) at concentrations over 11 mmol/l. In contrast, 22 mmol/l glucose increased alpha/beta SNAP biosynthesis about 2-fold only, similar to the increase in total protein synthesis. Stimulation of syntaxin 1 biosynthesis by glucose was also time-dependent, taking around 3 h to reach the maximum, and was not affected by actinomycin-D, suggesting regulation at the translational level. On the other hand, glucose had a similar stimulating effect on both syntaxin 1 and alpha/beta SNAP biosynthesis by mouse insulinoma betaTC3 cells as it did on proinsulin biosynthesis....Continue Reading

Citations

Jun 13, 2001·Biochemical and Biophysical Research Communications·H KatahiraH Ishida
Jun 25, 1999·Biochemical and Biophysical Research Communications·Y Nakamichi, S Nagamatsu
Jul 12, 2003·The Journal of Biological Chemistry·Tsugumichi SaitoMasatomo Mori

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