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Scientific article
English

Dynamin is functionally coupled to insulin granule exocytosis

Published inThe Journal of biological chemistry, vol. 282, no. 46, p. 33530-33536
Publication date2007
Abstract

The insulin granule integral membrane protein marker phogrin-green fluorescent protein was co-localized with insulin in Min6B1 beta-cell secretory granules but did not undergo plasma membrane translocation following glucose stimulation. Surprisingly, although expression of a dominant-interfering dynamin mutant (Dyn/K44A) inhibited transferrin receptor endocytosis, it had no effect on phogringreen fluorescent protein localization in the basal or secretagogue-stimulated state. By contrast, co-expression of Dyn/K44A with human growth hormone as an insulin secretory marker resulted in a marked inhibition of human growth hormone release by glucose, KCl, and a combination of multiple secretagogues. Moreover, serial pulse depolarization stimulated an increase in cell surface capacitance that was also blocked in cells expressing Dyn/K44A. Similarly, small interference RNA-mediated knockdown of dynamin resulted in marked inhibition of glucose-stimulated insulin secretion. Together, these data suggest the presence of a selective kiss and run mechanism of insulin release. Moreover, these data indicate a coupling between endocytosis and exocytosis in the regulation of beta-cell insulin secretion.

Keywords
  • Animals
  • Cell Line
  • Cell Membrane/metabolism
  • Dynamins/genetics/ physiology
  • Exocytosis
  • Green Fluorescent Proteins/metabolism
  • Insulin/ metabolism
  • Insulin-Secreting Cells/metabolism
  • Mice
  • Models, Biological
  • Mutation
  • Potassium Chloride/chemistry
  • Protein Transport
  • RNA, Small Interfering/metabolism
Citation (ISO format)
MIN, Le et al. Dynamin is functionally coupled to insulin granule exocytosis. In: The Journal of biological chemistry, 2007, vol. 282, n° 46, p. 33530–33536. doi: 10.1074/jbc.M703402200
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ISSN of the journal0021-9258
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