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Keywords

SNARE proteins, exocytosis, lipid membrane, protein structure

Abstract

Neurotransmitter release in neurons requires membrane fusion between synaptic vesicles and the presynaptic membrane. Lipids in both membranes merge through the action of SNARE proteins including SNAP-25. Changes in SNAP-25 structure or lipid composition likely modify this process. SNAP-25 has two isoforms, SNAP-25A (25A) and SNAP-25B (25B), the expression patterns of these isoforms vary throughout different brain regions and neuronal developmental stages. In vivo SNAP-25 anchors to the presynaptic membrane via attachment of palmitic acid to at least one of the four cysteines. Here we show mixing SNAP-25 (not palmitoylated) with liposomes alters both protein structure and lipid properties. Using circular dichroism (CD), we measured changes in secondary structure of SNAP-25 when mixed with liposomes made from DPPC, DPPC + Cholesterol, and POPC. Some lipids induced structural changes in SNAP-25 that were isoform dependent, consistent with a direct lipid-protein interaction. This proteinlipid interaction was confirmed by a shift in the DPPC melting temperature measured by differential scanning calorimetry (DSC). We hypothesize that neurons select the isoform and/or lipid composition ideal for the various forms of synaptic transmission.

Document Type

Poster

Publication Date

2026-03-26

Language

English

College

Life Sciences

Department

Cell Biology and Physiology

University Standing at Time of Publication

Senior

Cholesterol‑Containing Membranes Decrease the Helicity of the SNARE Protein SNAP‑25

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Life Sciences Commons

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