ISSN:
1432-0428
Keywords:
Keywords Syntaxin
;
SNAP
;
insulin biosynthesis
;
SNARE
;
glucose.
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary 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 α/β SNAP biosynthesis in pancreatic beta cells and we demonstrated that syntaxin 1, but not α/β 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 = ∼8 mmol/l) and reached the maximum (about 8–12 fold) at concentrations over 11 mmol/l. In contrast, 22 mmol/l glucose increased α/β 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 α/β SNAP biosynthesis by mouse insulinoma βTC3 cells as it did on proinsulin biosynthesis. The evidence showing coordinated stimulation of syntaxin 1 and proinsulin biosynthesis by glucose in rat islets suggested the critical functional role of syntaxin 1 in the insulin exocytotic mechanism. [Diabetologia (1997) 40: 1396–1402]
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s001250050841
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