Mastoparan stimulates GABA release from MIN6 cells: relationship between SNARE proteins and mastoparan action.
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.
Ohara-Imaizumi
M
M
Department of Biochemistry, Kyorin University School of Medicine, Mitaka, Tokyo, 181-8611, Japan.
Nakamichi
Y
Y
Ozawa
S
S
Katsuta
H
H
Ishida
H
H
Nagamatsu
S
S
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*
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