A conformational switch in syntaxin during exocytosis

Role of munc18

Irina Dulubova, Shuzo Sugita, Sandra Hill, Masahiro Hosaka, Imma Fernandez, Thomas C. Südhof, Jose Rizo-Rey

Research output: Contribution to journalArticle

488 Citations (Scopus)

Abstract

Syntaxin 1, an essential protein in synaptic membrane fusion, contains a helical autonomously folded N-terminal domain, a C-terminal SNARE motif and a transmembrane region. The SNARE motif binds to synaptobrevin and SNAP-25 to assemble the core complex, whereas almost the entire cytoplasmic sequence participates in a complex with munc18-1, a neuronal Sec1 homolog. We now demonstrate by NMR spectroscopy that, in isolation, syntaxin adopts a 'closed' conformation. This default conformation of syntaxin is incompatible with core complex assembly which requires an 'open' syntaxin conformation. Using site-directed mutagenesis, we find that disruption of the closed conformation abolishes the ability of syntaxin to bind to munc18-1 and to inhibit secretion in PC12 cells. These results indicate that syntaxin binds to munc18-1 in a closed conformation and suggest that this conformation represents an essential intermediate in exocytosis. Our data suggest a model whereby, during exocytosis, syntaxin undergoes a large conformational switch that mediates the transition between the syntaxin-munc18-1 complex and the core complex.

Original languageEnglish (US)
Pages (from-to)4372-4382
Number of pages11
JournalEMBO Journal
Volume18
Issue number16
DOIs
StatePublished - Aug 16 1999

Fingerprint

Qa-SNARE Proteins
Exocytosis
Conformations
Switches
Syntaxin 1
SNARE Proteins
R-SNARE Proteins
Synaptic Membranes
Membrane Fusion
PC12 Cells
Mutagenesis
Site-Directed Mutagenesis
Magnetic Resonance Spectroscopy
Nuclear magnetic resonance spectroscopy
Fusion reactions
Membranes

Keywords

  • Exocytosis
  • Munc18
  • Protein NMR
  • SNARE
  • Syntaxin

ASJC Scopus subject areas

  • Genetics
  • Cell Biology

Cite this

Dulubova, I., Sugita, S., Hill, S., Hosaka, M., Fernandez, I., Südhof, T. C., & Rizo-Rey, J. (1999). A conformational switch in syntaxin during exocytosis: Role of munc18. EMBO Journal, 18(16), 4372-4382. https://doi.org/10.1093/emboj/18.16.4372

A conformational switch in syntaxin during exocytosis : Role of munc18. / Dulubova, Irina; Sugita, Shuzo; Hill, Sandra; Hosaka, Masahiro; Fernandez, Imma; Südhof, Thomas C.; Rizo-Rey, Jose.

In: EMBO Journal, Vol. 18, No. 16, 16.08.1999, p. 4372-4382.

Research output: Contribution to journalArticle

Dulubova, I, Sugita, S, Hill, S, Hosaka, M, Fernandez, I, Südhof, TC & Rizo-Rey, J 1999, 'A conformational switch in syntaxin during exocytosis: Role of munc18', EMBO Journal, vol. 18, no. 16, pp. 4372-4382. https://doi.org/10.1093/emboj/18.16.4372
Dulubova I, Sugita S, Hill S, Hosaka M, Fernandez I, Südhof TC et al. A conformational switch in syntaxin during exocytosis: Role of munc18. EMBO Journal. 1999 Aug 16;18(16):4372-4382. https://doi.org/10.1093/emboj/18.16.4372
Dulubova, Irina ; Sugita, Shuzo ; Hill, Sandra ; Hosaka, Masahiro ; Fernandez, Imma ; Südhof, Thomas C. ; Rizo-Rey, Jose. / A conformational switch in syntaxin during exocytosis : Role of munc18. In: EMBO Journal. 1999 ; Vol. 18, No. 16. pp. 4372-4382.
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