Small peptides patterned after the N-terminus domain of SNAP25 inhibit SNARE complex assembly and regulated exocytosis.
Synthetic peptides patterned after the C-terminus of synaptosomal associated protein of 25 kDa (SNAP25) efficiently abrogate regulated exocytosis. In contrast, the use of SNAP25 N-terminal-derived peptides to modulate SNAP receptors (SNARE) complex assembly and neurosecretion has not been explored. Here, we show that the N-terminus of SNAP25, specially the segment that encompasses 22Ala-44Ile, is essential for the formation of the SNARE complex. Peptides patterned after this protein domain are potent inhibitors of SNARE complex formation. The inhibitory activity correlated with their propensity to adopt an alpha-helical secondary structure. These peptides abrogated SNARE complex formation only when added previous to the onset of aggregate assembly. Analysis of the mechanism of action revealed that these peptides disrupted the binary complex formed by SNAP25 and syntaxin. The identified peptides inhibited Ca2+-dependent exocytosis from detergent-permeabilized excitable cells. Noteworthy, these amino acid sequences markedly protected intact hippocampal neurones against hypoglycaemia-induced, glutamate-mediated excitotoxicity with a potency that rivalled that displayed by botulinum neurotoxins. Our findings indicate that peptides patterned after the N-terminus of SNAP25 are potent inhibitors of SNARE complex formation and neuronal exocytosis. Because of their activity in intact neurones, these cell permeable peptides may be hits for antispasmodic and analgesic drug development.
Blanes-Mira
Clara
C
Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, Alicante, Spain.
Merino
Jaime M
JM
Valera
Elvira
E
Fernández-Ballester
Gregorio
G
Gutiérrez
Luis M
LM
Viniegra
Salvador
S
Pérez-Payá
Enrique
E
Ferrer-Montiel
Antonio
A
D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002395:Catecholamines / Q000378:metabolism; D002417:Cattle; D016923:Cell Death / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D019439:Chromaffin Cells / Q000187:drug effects / Q000378:metabolism; D003902:Detergents / Q000737:chemistry / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005089:Exocytosis / Q000187:drug effects / Q000502:physiology*; D005947:Glucose / Q000172:deficiency / Q000378:metabolism / Q000494:pharmacology; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism; D009474:Neurons / Q000187:drug effects; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D017434:Protein Structure, Tertiary / Q000502:physiology; D050600:SNARE Proteins; D013329:Structure-Activity Relationship; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins
D002395:Catecholamines; D003902:Detergents; D046911:Macromolecular Substances; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D010455:Peptides; D050600:SNARE Proteins; D050825:Synaptosomal-Associated Protein 25; D033921:Vesicular Transport Proteins; D005947:Glucose; D002118:Calcium