SNAP25 disease mutations change the energy landscape for synaptic exocytosis due to aberrant SNARE interactions
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SNAP25 disease mutations change the energy landscape for synaptic exocytosis due to aberrant SNARE interactions. / Kádková, Anna; Murach, Jacqueline; Østergaard, Maiken; Malsam, Andrea; Malsam, Jörg; Lolicato, Fabio; Nickel, Walter; Söllner, Thomas H; Sørensen, Jakob Balslev.
In: eLife, Vol. 12, 2024.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - SNAP25 disease mutations change the energy landscape for synaptic exocytosis due to aberrant SNARE interactions
AU - Kádková, Anna
AU - Murach, Jacqueline
AU - Østergaard, Maiken
AU - Malsam, Andrea
AU - Malsam, Jörg
AU - Lolicato, Fabio
AU - Nickel, Walter
AU - Söllner, Thomas H
AU - Sørensen, Jakob Balslev
N1 - © 2023, Kádková, Murach, Østergaard et al.
PY - 2024
Y1 - 2024
N2 - SNAP25 is one of three neuronal SNAREs driving synaptic vesicle exocytosis. We studied three mutations in SNAP25 that cause epileptic encephalopathy: V48F, and D166Y in the synaptotagmin-1 (Syt1)-binding interface, and I67N, which destabilizes the SNARE complex. All three mutations reduced Syt1-dependent vesicle docking to SNARE-carrying liposomes and Ca2+-stimulated membrane fusion in vitro and when expressed in mouse hippocampal neurons. The V48F and D166Y mutants (with potency D166Y > V48F) led to reduced readily releasable pool (RRP) size, due to increased spontaneous (miniature Excitatory Postsynaptic Current, mEPSC) release and decreased priming rates. These mutations lowered the energy barrier for fusion and increased the release probability, which are gain-of-function features not found in Syt1 knockout (KO) neurons; normalized mEPSC release rates were higher (potency D166Y > V48F) than in the Syt1 KO. These mutations (potency D166Y > V48F) increased spontaneous association to partner SNAREs, resulting in unregulated membrane fusion. In contrast, the I67N mutant decreased mEPSC frequency and evoked EPSC amplitudes due to an increase in the height of the energy barrier for fusion, whereas the RRP size was unaffected. This could be partly compensated by positive charges lowering the energy barrier. Overall, pathogenic mutations in SNAP25 cause complex changes in the energy landscape for priming and fusion.
AB - SNAP25 is one of three neuronal SNAREs driving synaptic vesicle exocytosis. We studied three mutations in SNAP25 that cause epileptic encephalopathy: V48F, and D166Y in the synaptotagmin-1 (Syt1)-binding interface, and I67N, which destabilizes the SNARE complex. All three mutations reduced Syt1-dependent vesicle docking to SNARE-carrying liposomes and Ca2+-stimulated membrane fusion in vitro and when expressed in mouse hippocampal neurons. The V48F and D166Y mutants (with potency D166Y > V48F) led to reduced readily releasable pool (RRP) size, due to increased spontaneous (miniature Excitatory Postsynaptic Current, mEPSC) release and decreased priming rates. These mutations lowered the energy barrier for fusion and increased the release probability, which are gain-of-function features not found in Syt1 knockout (KO) neurons; normalized mEPSC release rates were higher (potency D166Y > V48F) than in the Syt1 KO. These mutations (potency D166Y > V48F) increased spontaneous association to partner SNAREs, resulting in unregulated membrane fusion. In contrast, the I67N mutant decreased mEPSC frequency and evoked EPSC amplitudes due to an increase in the height of the energy barrier for fusion, whereas the RRP size was unaffected. This could be partly compensated by positive charges lowering the energy barrier. Overall, pathogenic mutations in SNAP25 cause complex changes in the energy landscape for priming and fusion.
KW - Animals
KW - Mice
KW - Membrane Fusion
KW - Synaptic Transmission
KW - Exocytosis
KW - Mutation
KW - SNARE Proteins/genetics
U2 - 10.7554/eLife.88619
DO - 10.7554/eLife.88619
M3 - Journal article
C2 - 38411501
VL - 12
JO - eLife
JF - eLife
SN - 2050-084X
ER -
ID: 387029666