A role for soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex dimerization during neurosecretion.
The interactions underlying the cooperativity of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes during neurotransmission are not known. Here, we provide a molecular characterization of a dimer formed between the cytoplasmic portions of neuronal SNARE complexes. Dimerization generates a two-winged structure in which the C termini of cytosolic SNARE complexes are in apposition, and it involves residues from the vesicle-associated SNARE synaptobrevin 2 that lie close to the cytosol-membrane interface within the full-length protein. Mutation of these residues reduces stability of dimers formed between SNARE complexes, without affecting the stability of each individual SNARE complex. These mutations also cause a corresponding decrease in the ability of botulinum toxin-resistant synaptobrevin 2 to rescue regulated exocytosis in toxin-treated neuroendocrine cells. Moreover, such synaptobrevin 2 mutants give rise to a dominant-negative inhibition of exocytosis. These data are consistent with an important role for SNARE complex dimers in neurosecretion.
Institute of Parasitology and Biomedicine López-Neyra, Consejo Superior de Investigaciones Cientificas, 18100 Granada, Spain.
Elena
E
Fdez
Thomas A
TA
Jowitt
Ming-Chuan
MC
Wang
Manisha
M
Rajebhosale
Keith
K
Foster
Jordi
J
Bella
Clair
C
Baldock
Philip G
PG
Woodman
Sabine
S
Hilfiker
D000818:Animals; D001905:Botulinum Toxins / Q000494:pharmacology; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D019281:Dimerization; D005089:Exocytosis; D031541:Fluorescence Resonance Energy Transfer; D046529:Microscopy, Electron, Transmission; D008954:Models, Biological; D008968:Molecular Conformation; D009474:Neurons / Q000378:metabolism; D016716:PC12 Cells; D051381:Rats; D050600:SNARE Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D050988:Vesicle-Associated Membrane Protein 2 / Q000378:metabolism
D050600:SNARE Proteins; D050988:Vesicle-Associated Membrane Protein 2; D001905:Botulinum Toxins