title: Mastoparan stimulates GABA release from MIN6 cells: relationship between SNARE proteins and mastoparan action.
abstract: We examined the action of mastoparan on beta cell exocytosis. Mastoparan stimulated GABA and insulin release from MIN6 beta cells. On the other hand, mastopraran-induced GABA release was decreased by expressing the tetanus toxin C1 light chain in MIN6 cells. We have then investigated the relationship between SNARE proteins and mastoparan action using adenovirus-mediated gene transfer system. Overexpression of t-SNAREs, syntaxin 1A, and SNAP-25 inhibited the mastoparan-induced insulin release by approximately half-fold of control levels, however, the mastoparan-induced GABA release was not affected by these t-SNAREs overexpression. The overexpression of mutant alpha-SNAP (1-285), which inhibits the wild-type alpha-SNAP function in a dominant negative manner, did not influence either mastoparan-induced GABA or insulin release in spite of its marked inhibition of glucose-stimulated insulin release. Our data indicate that mastoparan stimulates GABA exocytosis via vesicular transport; however, SNARE proteins are differently involved in the exocytosis of insulin and GABA.
authors.affiliation: Department of Biochemistry, Kyorin University School of Medicine, Mitaka, Tokyo, 181-8611, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Ohara-Imaizumi
authors.forename: Y
authors.initials: Y
authors.lastname: Nakamichi
authors.forename: S
authors.initials: S
authors.lastname: Ozawa
authors.forename: H
authors.initials: H
authors.lastname: Katsuta
authors.forename: H
authors.initials: H
authors.lastname: Ishida
authors.forename: S
authors.initials: S
authors.lastname: Nagamatsu
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology; D002460:Cell Line; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D036341:Intercellular Signaling Peptides and Proteins; D007515:Islets of Langerhans / Q000187:drug effects / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D051379:Mice; D009154:Mutation; D010455:Peptides; D050600:SNARE Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D050827:Syntaxin 1; D033921:Vesicular Transport Proteins; D014862:Wasp Venoms / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D007328:Insulin; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D010455:Peptides; D050600:SNARE Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; C494214:Stx1a protein, mouse; D050827:Syntaxin 1; D033921:Vesicular Transport Proteins; D014862:Wasp Venoms; D005680:gamma-Aminobutyric Acid; C037500:mastoparan