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Scientific article
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SNAP-23 is not cleaved by botulinum neurotoxin E and can replace SNAP-25 in the process of insulin secretion

Published inThe Journal of biological chemistry, vol. 272, no. 52, p. 33023-33027
Publication date1997
Abstract

The synaptosomal-associated protein of 25 kDa (SNAP-25) is expressed in neurons and endocrine cells. It has been shown to play an important role in the release mechanism of neurotransmitters and peptide hormones, including insulin. Thus, when insulin-secreting cells are permeabilized and treated with botulinum neurotoxin E (BoNT/E), SNAP-25 is hydrolyzed, and insulin secretion is inhibited. Recently SNAP-23, a more generally expressed isoform of SNAP-25, has been described. The functional role of SNAP-23 has not been investigated to date. It is now shown that SNAP-23 is resistant to cleavage by BoNT/E. It was therefore possible to test whether transfection of HIT (transformed pancreatic B-) cells with SNAP-23 reconstitutes insulin release from BoNT/E treated cells, in which SNAP-25 is inactivated by the toxin. The results show that SNAP-23 is able to replace SNAP-25 when it is overexpressed. While these results demonstrate that SNAP-23 is a functional homologue of SNAP-25, able to function in regulated exocytosis, they indicate that SNAP-23 may be inefficient in this process. This suggests that both isoforms may have their own specific binding partners and discrete, albeit mechanistically similar, functional roles within the cell.

Keywords
  • Animals
  • Botulinum Toxins/ metabolism
  • Carrier Proteins/genetics/ metabolism
  • Cricetinae
  • Fluorescent Antibody Technique, Indirect
  • Insulin/ secretion
  • Membrane Proteins
  • Nerve Tissue Proteins/genetics/ metabolism
  • Qb-SNARE Proteins
  • Qc-SNARE Proteins
  • Synaptosomal-Associated Protein 25
  • Transfection
  • Tumor Cells, Cultured
Citation (ISO format)
SADOUL, Karin et al. SNAP-23 is not cleaved by botulinum neurotoxin E and can replace SNAP-25 in the process of insulin secretion. In: The Journal of biological chemistry, 1997, vol. 272, n° 52, p. 33023–33027. doi: 10.1074/jbc.272.52.33023
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ISSN of the journal0021-9258
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