Regulation of neuronal SNARE assembly by the membrane.
In the neuron, SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) assembly acts centrally in driving membrane fusion, a required process for neurotransmitter release. In the cytoplasm, vesicular SNARE VAMP-2 (vesicle-associated membrane protein-2) engages with two plasma membrane SNAREs, syntaxin 1A and SNAP-25 (synaptosome-associated protein of 25 kDa), to form the core complex that bridges two membranes. Although various factors regulate SNARE assembly, the membrane also aids in regulation by trapping VAMP-2 in the membrane. Fluorescence and EPR analyses revealed that the insertion of seven C-terminal core-forming residues into the membrane controls complex formation of the entire core region, even though the preceding 54 core-forming residues are fully exposed and freely moving. When two interfacial tryptophan residues in this region were replaced with hydrophilic serine residues, the mutation supported rapid complex formation. The results suggest that the membrane-proximal region of VAMP-2 is a regulatory module for SNARE assembly, providing new insights into calcium-triggered membrane fusion.
Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA.
Dae-Hyuk
DH
Kweon
Chang Sup
CS
Kim
Yeon-Kyun
YK
Shin
D000954:Antigens, Surface / Q000737:chemistry / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D008051:Lipid Bilayers; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism*; D050683:R-SNARE Proteins; D050600:SNARE Proteins; D013050:Spectrometry, Fluorescence; D050825:Synaptosomal-Associated Protein 25; D050827:Syntaxin 1; D014364:Tryptophan / Q000737:chemistry / Q000378:metabolism; D033921:Vesicular Transport Proteins
D000954:Antigens, Surface; D008051:Lipid Bilayers; D046911:Macromolecular Substances; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050683:R-SNARE Proteins; D050600:SNARE Proteins; D050825:Synaptosomal-Associated Protein 25; D050827:Syntaxin 1; D033921:Vesicular Transport Proteins; D014364:Tryptophan