GSBS Student Publications

Title

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

Student Author(s)

James McNally

GSBS Program

Neuroscience

Publication Date

2004-09-17

UMMS Affiliation

Department of Physiology

Document Type

Article

Disciplines

Life Sciences | Medicine and Health Sciences | Neuroscience and Neurobiology

Abstract

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.

DOI of Published Version

10.1385/CBB:41:1:011

Source

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

Journal/Book/Conference Title

Cell biochemistry and biophysics

Related Resources

Link to article in PubMed

PubMed ID

15371637

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