GSBS Student Publications


Syntaxin 1A Drives Fusion of Large Dense-Core Neurosecretory Granules Into a Planar Lipid Bilayer

Student Author(s)

James McNally

GSBS Program


UMMS Affiliation

Department of Physiology



Document Type


Medical Subject Headings

Lipid Bilayers; Secretory Vesicles; Syntaxin 1


Life Sciences | Medicine and Health Sciences | Neuroscience and Neurobiology


The SNARE complex, involved in vesicular trafficking and exocytosis, is composed of proteins in the vesicular membrane (v-SNAREs) that intertwine with proteins of the target membrane (t-SNAREs). Our results show that modified large dense-core neurosecretory granules (NSGs), isolated from the bovine neurohypophysis, spontaneously fuse with a planar lipid membrane containing only the t-SNARE syntaxin 1A. This provides evidence that syntaxin alone is able to form a functional fusion complex with native v-SNAREs of the NSG. The fusion was similar to constitutive, not regulated, exocytosis because changes in free [Ca2+] had no effect on the syntaxin-mediated fusion. Several deletion mutants of syntaxin 1A were also tested. The removal of the regulatory domain did not significantly reduce spontaneous fusion. However, a syntaxin deletion mutant consisting of only the transmembrane domain was incapable of eliciting spontaneous fusion. Finally, a soluble form of syntaxin 1A (lacking its transmembrane domain) was used to saturate the free syntaxin-binding sites of modified NSGs. This treatment blocks spontaneous fusion of these granules to a bilayer containing full-length syntaxin 1A. This method provides an effective model system to study possible regulatory components affecting vesicle fusion.

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Citation: Cell Biochem Biophys. 2004;41(1):11-24. Link to article on publisher's site

DOI of Published Version


Related Resources

Link to article in PubMed

Journal Title

Cell biochemistry and biophysics

PubMed ID