EMBO/soda-nel huggingface dataset:
mGluR-Long Term Depression regulates GluA2 association with COPII vesicles and exit from the endoplasmic reticulum (2016)
Figure 3

Figure 3. DHPG regulates GluA2, but not GluA1, exit from the ER in an ER Ca2+ dependent manner.

A. Top. Representative image of a radiograph of mature and immature bands of GluA2 after no treatment, DHPG, or 2APB/dan followed by DHPG and incubated with Endo H. Bottom. Quantified graph of the ratio of the mature, endo H insensitive GluA2 band to the total GluA2 for each condition. For DHPG, n = 16; for DHPG + 2APB/dan, n = 11, p < 0.05, ANOVA. B. Top. Representative image of a radiograph of mature and immature bands of GluA1 after no treatment, DHPG, or 2APB/dan followed by DHPG and incubated with Endo H. Bottom. Quantified graph of the ratio of the mature, endo H insensitive GluA1 band to the total GluA1 for each condition, For DHPG, n = 4; for DHPG + 2APB/dan, n = 4, ANOVA. C. Representative images of surface GluA2 and DARPP32 expression in striatal neurons from co-cultures with either no DHPG or 30 min DHPG after 15 min of brefeldin A treatment. D. Quantified expression of surface GluA2 under each condition, n = 3 replicates of 10 cells each, Student’s t test. All error bars represent s.e.m.
mGluR-Long Term Depression regulates GluA2 association with COPII vesicles and exit from the endoplasmic reticulum (2016)
Figure 4

Figure 4. DHPG drives increased association between GluA2 and the COPII vesicle protein, Sec23.

A Top. Representative immunoblots from GluA2 coimmunoprecipitations probed for Sec23 and GluA2 after no treatment, 10 min DHPG, and 2APB/dantrolene followed by 10 min DHPG. Bottom. Quantification of Sec23 normalized to GluA2 under each of these conditions. For 10 min DHPG, n = 8; for 10 min DHPG + 2APB/dan, n = 6, p < 0.05, ANOVA. B. Top. Representative immunoblots from GluA2 coimmunoprecipitations probed for Sec23 and GluA2 after no treatment, 10 min DHPG, and and cycloheximide followed by 10 min DHPG. Bottom. Quantification of Sec23 normalized to GluA2 under each of these conditions, For 10 min DHPG, n = 8; for 10 min DHPG + CHX, n = 5, p < 0.05, ANOVA. C. Top. Representative immunoblots from GluA2 co-IPs probed for Sec23 and GluA2 after no treatment, 30 min DHPG, and 2APB/dantrolene followed by 30 min DHPG. Bottom. Quantification of Sec23 normalized to GluA2 under each of these conditions. For 30 min DHPG, n = 17; For 30 min DHPG + 2APB/dan, n = 14, p < 0.05, ANOVA. D. Top. Representative immunoblots from GluA2 coimmunoprecipitations probed for Sec23 and GluA2 after no treatment, 30 min DHPG, and cycloheximide followed by 30 min DHPG. Bottom. Quantification of Sec23 normalized to GluA2 under each of these conditions. For 30 min DHPG, n = 12; For 30 min DHPG + CHX, n = 11 p < 0.01, ANOVA. E. Top. Representative immunoblot demonstrating IgG and GluA2 coIP after no treatment and 30 min DHPG. Bottom. Quantification of Sec23 after subtracting the non-specific signal, n = 3, p < 0.01, Student’s t test. F. Representative immunoblot of a control coIP that demonstrates the specificity of the GluA2 coIP. All error bars represent s.e.m.
mGluR-Long Term Depression regulates GluA2 association with COPII vesicles and exit from the endoplasmic reticulum (2016)
Figure 5

Figure 5. The kinetics of GluA2 association with Sec23 after DHPG treatment.

A. Representative immunoblots from GluA2 coIP probed for Sec23, Sec13, and GluA2 after no DHPG, 10, 30, and 60 minutes of treatment with DHPG. B. Graph depicting the kinetics of the association between GluA2 and Sec23 as well as GluA2 and Sec13 after treatment with DHPG for the same points in time as in A. For Sec23, 10 min DHPG, n = 16; 30 min DHPG, n = 15; 60 min DHPG, n = 7, p < 0.0001, ANOVA. For Sec13, 10 min DHPG, n = 7; 30 min DHPG, n = 14; 60 min DHPG, n = 6, p < 0.01, ANOVA. C. Representative images of total expression levels of Sec23 (top) and Sec13 (bottom). Expression levels do not change in the presence of DHPG. All error bars represent s.e.m.
[BioStudies]_Tyrosine phosphorylation of Munc18-1 inhibits synaptic transmission by preventing SNARE assembly (2017)
Figure 1

Figure 1. Src-family kinases target Munc18-1 on Y473

(A) Using denaturing immunoprecipitation (IP), Munc18-1 was isolated from cell lysate of HEK293T cells expressing M18WT, M18Y145F or M18Y473F together with or without n-Src. Munc18-1 was immunoblotted for tyrosine phosphorylation using the 4G10 antibody (αPtyr), after which the blot was stripped and re-blotted for Munc18-1. Total lysate (TL) is shown as loading control. N-Src was tagged with a flag-tag for visualization.

(B) Same as (A) but using lysate from HEK293T cells expressing M18WT or M18Y473F together with or without n-Src, c-Src or Fyn. The first two lanes are IPs performed using empty beads to control for non-specific binding of Munc18 or kinases to the beads.

(C) Alignment of amino acid sequence surrounding Y473 of mouse Munc18 isoforms and of Munc18-1 across different species. Grey-marked residues are identical to mouse Munc18-1.

(D) Crystal structure of Munc18-1 (grey) and Syntaxin1 (cyan) adapted from (Misura et al., 2000) showing residue Y473 in red and helix 11-12 of domain 3a in orange.

(E) Incubation scheme: GUVs (14 nmol lipid) containing preassembled t-SNAREs (14 pmol Syx1/SNAP-25) were mixed on ice with the indicated Munc18-1 constructs (90 pmol) and subsequently SUVs (2.5 nmol lipid) containing Synaptotagmin1 (3 pmol) and Synaptobrevin/VAMP2 (8 pmol) were added. The fusion reaction was started by warming up the liposomes to 37 °C. Calcium (100 µM final concentration) was added after 2 minutes.

(F) Lipid mixing was monitored by the increase of Atto 488 fluorescence for 12 minutes. Data were normalized to the maximum fluorescence after liposome lysis by detergent. Error bars = s.e.m., N = 3.

(G) Same as (E-F) but the reactions were preincubated on ice for 5 minutes in the presence of Complexin II (CpxII 600 pmol). Error bars = s.e.m., N =5.

(H) Incubation scheme: GUVs (14 nmol lipid) containing Syx1 (14 pmol) were preincubated with the indicated Munc18-1 constructs (90 pmol) at room temperature for 30 min. Subsequently, samples were incubated with soluble SNAP-25 (128 pmol) and SUVs (2.5 nmol lipid) containing Synaptotagmin1 (3 pmol) and VAMP8 (8 pmol) for 5 min on ice. Lipid mixing was started by increasing the temperature to 37 oC.

(I) Lipid mixing was monitored by the increase of Atto 488 fluorescence for 60 minutes. Data were normalized to the maximum fluorescence after liposome lysis by detergent. Error bars = s.e.m., N =3.
[BioStudies]_Tyrosine phosphorylation of Munc18-1 inhibits synaptic transmission by preventing SNARE assembly (2017)
Figure 2

Figure 2. Tyrosine phosphorylation of Munc18-1 disrupts basal synaptic transmission in autaptic neurons.

Autaptic munc18-1 null hippocampal neurons were rescued with a phosphomimetic Munc18-1 mutant, Y473D or wild-type Munc18-1 as control and assessed on morphology and synaptic transmission using confocal microscopy (A-B) and whole-cell patch clamp electrophysiology (C-G) respectively.

(A) Typical confocal images from neurons stained for MAP2, Synaptobrevin/VAMP2 and Munc18-1.

(B) Average synaptic Munc18-1 intensity (M18WT: 389 ± 85 a.u., n=21; M18Y473D: 261 ± 49 a.u., n=20, t-test with Welch correction, p = 0.2000), somatic Munc18-1 intensity (M18WT: 328 ± 49 a.u., n=21; M18Y473D: 188 ± 21 a.u., n=20, t-test with Welch correction, p = 0.0138), synapse number (M18WT: 129 ± 14, n=21; M18Y473D: 159 ± 14, n=20, t-test, p = 0.1203) and dendrite length (M18WT: 0.433 ± 0.028, n=21; M18Y473D: 0.454 ± 0.037, n=20, t-test, p = 0.6613).

(C) Left: typical examples of evoked release upon action potential stimulation.

Average EPSC amplitude (M18WT: 7.96 ± 0.94 nA, n=30; M18Y473D: 0.12 ± 0.05 nA, n=30, Mann-Whitney U test, p < 0.0001).

(D) Left: typical responses to hyperosmotic sucrose application (500 mM, 3.5 sec.) used to assess the RRP. Average RRP charge (M18WT: 1.68 ± 0.64 nC, n=13; M18Y473D: 0.08 ± 0.02 nC, n=10, t-test with Welch correction, p = 0.0274).

(E) Average Pves (EPSC charge / RRP charge) (M18WT: 6.75 ± 0.77%, n=13; M18Y473D: 0.24 ± 0.20%, n=10; Mann-Whitney U test, p < 0.0001).

(F) Left: example traces of spontaneous release of single SVs (mEPSCs). Average mEPSC frequency (M18WT: 20.18 ± 5.18 Hz, n=15; M18Y473D: 0.28 ± 0.13 Hz, n=17, Mann-Whitney U test, p < 0.0001), mEPSC amplitude (M18WT: 26.0 ± 1.7 pA, n=15; M18Y473D: 27.8 ± 2.2 pA, n=17, t-test, p = 0.5372) and mEPSC decay time (M18WT: 1.98 ± 0.10 ms, n=15; M18Y473D: 2.84 ± 0.41 ms, n=17, t-test with Welch correction, p = 0.0549).
[BioStudies]_Tyrosine phosphorylation of Munc18-1 inhibits synaptic transmission by preventing SNARE assembly (2017)
Figure 3

Figure 3. Docked synaptic vesicles are halted in a pre-primed state.

Neurons expressing M18Y473D are not impaired at SV docking. Autaptic munc18-1 null hippocampal neurons expressing M18Y473D or M18WT as controls were analysed with electron microscopy on chemically fixed samples (A-F) and cryofixed samples (G-J) in separate experiments.

(A) Typical electron microscopy images from both groups. Scale bar = 100nm.

(B) Average number of docked SV (M18WT: 7.63 ± 0.15 SVs; M18Y473D: 8.45 ± 0.20 docked SVs, multilevel analysis, p = 0.047).

(C) Total number of SVs is not different (M18WT: 142 ± 11 SVs; M18Y473D: 148 ± 15 SVs, multilevel analysis, p = 0.456).

(D) The active zone (AZ) length is similar (M18WT: 561 ± 24 nm; M18Y473D: 646 ± 59 nm, multilevel analysis, p = 0.161).

(E) There is no change in the number of docked SVs per AZ length (M18WT: 14.0 ± 0.6 docked SVs/pm AZ; M18Y473D: 14.1 ± 0.9 docked SVs/pm AZ, multilevel analysis, p = 0.934).

(B-E) M18WT : N=6 autaptic neurons, n=137 synapses; M18Y473D: N=8 autaptic neurons, n=116 synapses.

(F) Typical electron microscopy images from both groups. Scale bar = 200nm.

(G) Average number of docked SV is equal (M18WT: 10.17 ± 0.38 SVs; M18Y473D: 10.75 ± 0.40 docked SVs, multilevel analysis, p = 0.264).

(H) Total number of SVs is similar (M18WT: 160.2 ± 9.7 SVs; M18Y473D: 176.7 ± 9.2 SVs, multilevel analysis, p = 0.212).

(I) The active zone (AZ) length is similar (M18WT: 740.2 ± 29.7 nm; M18Y473D: 771.4 ± 28.1 nm, multilevel analysis, p = 0.871).

(J) There is no change in the number of docked SVs per AZ length (M18WT: 14.36 ± 0.32 docked SVs/pm AZ; M18Y473D: 14.34 ± 0.32 docked SVs/pm AZ, multilevel analysis, p = 0.969).

(G-J) M18WT : N=3 independent cultures, n=159 synapses; M18Y473D: N=3 independent cultures, n=156 synapses.
[BioStudies]_Tyrosine phosphorylation of Munc18-1 inhibits synaptic transmission by preventing SNARE assembly (2017)
Figure 4

Figure 4. Synaptic transmission is partly restored during sustained stimulation.

Synaptic transmission was assessed during and immediately after sustained stimulation in autaptic excitatory munc18-1 neurons expressing M18WT or M18Y473D.

(A) Rundown of EPSC amplitude during 100 pulses at 10 Hz. Top: example traces of the current evoked by 40Hz stimulation.

(B) EPSC charge during 100 pulses at 40 Hz. Top: example traces of the current evoked by 40Hz stimulation. Insert shows total charge transferred during entire train (M18WT: 2.63 ± 0.38 nC; M18Y473D: 1.48 ± 0.24 nC, t test with Welch correction, p = 0.0177).

(C) Synaptic transmission was assessed before (naive(n)) and two seconds after (a) 40Hz stimulation. Average EPSC charge M18WT (naive: 70.9 ± 19.5 pC; after HFS: 75.4 ± 17.4 pC, n=12, paired t-test, p = 0.4049). Average EPSC charge M18Y473D (naive: 0.888 ± 0.342 pC, after HFS: 25.6 ± 9.3 pC, n=9, paired t-test, p = 0.0271).

(D) A hypertonic sucrose solution (500 mM, 3.5 sec.) was applied to release the RRP before (naive (n)) or two seconds after (a) HFS (100 pulses at 40 Hz).

(E) Quantification of RRP and Pves (EPSC charge / RRP charge * 100) from C-D. Average RRP size M18WT (naive: 1.73 ± 0.69 nC, after HFS: 1.34 ± 0.54 nC, n=12, paired t-test, p = 0.0557). Average RRP size M18Y473D (Naive: 0.061 ± 0.019 nC, after HFS: 0.207 ± 0.050 nC, n=9, paired t-test, p = 0.0246). Average Pves M18WT (naive: 7.07 ± 0.76 %, after HFS: 10.6 ± 1.6 %, n=12, paired t-test, p = 0.0201). Average Pves M18Y473D (naive: 0.27 ± 0.22 %, after HFS: 10.8 ± 2.2%, n=9, paired t-test, p = 0.0012).

(F) PDBu application (1 µM) enhanced EPSC size in neurons expressing M18Y473D.
[BioStudies]_Tyrosine phosphorylation of Munc18-1 inhibits synaptic transmission by preventing SNARE assembly (2017)
Figure 5

Figure 5. Promoting helix 12 extension partly rescues the inhibitory effect of Y473D

(A) Left: closed helical hairpin in domain 3a as identified in the Munc18-1:closed-Syntaxin1 crystal structure (Misura et al., 2000). Right: extended helical hairpin as observed in the crystal of Munc18-1 bound to the N-peptide of Syntaxin-4 (Hu et al., 2011).

(B) GST-Munc18-1 constructs were immobilized on glutathione beads and incubated with the indicated molar excess of Synaptobrevin/VAMP2 (over Munc18-1) for 1.5 h at 4°C. Bound Synaptobrevin/VAMP2 was analyzed by Western blot and immune decorating with an anti-Synaptobrevin/VAMP2 antibody and quantified by the LICORE system and ImageJ software. Synaptobrevin/VAMP2 bound to the GST-Munc18-1 mutants is represented as percentage of Synaptobrevin/VAMP2 bound to GST-Munc18-1 WT. Error bars indicate s.e.m., n=3.

(C) GUVs (14 nmol lipid) containing Syx1 (14 pmol) were pre-incubated with the indicated Munc18-1 constructs (90 pmol) at room temperature for 30 min. Subsequently, samples were incubated with soluble SNAP-25 (128 pmol) and SUVs (2.5 nmol lipid) containing Synaptotagmin1 (3 pmol) and SSynaptobrevin/VAMP2 (8 pmol) for 15 min on ice. Lipid mixing was started by increasing the temperature to 37 °C.

(D) Lipid mixing was monitored by the increase of Atto 655 fluorescence for 30 minutes. Data were normalized to the maximum fluorescence after liposome lysis by detergent. The minimum fluorescence was set to 0%. Error bars = s.e.m., N = 3.

(E) Trans-SNARE Formation Assay: t- and v-SNARE SUVs were incubated in the presence or absence of different Munc18-1 constructs for 30min at 4°C. After solubilization and precipitation of the t-SNAREs using nickel beads, presence of full-length VAMP2 in the precipitates was probed by immunoblotting, which was used as an indicator for trans-SNARE assembly between SUVs.
[BioStudies]_Tyrosine phosphorylation of Munc18-1 inhibits synaptic transmission by preventing SNARE assembly (2017)
Figure 6

Figure 6. Promoting helix 12 extension partly rescues synaptic transmission

Evoked and spontaneous release in autaptic munc18-1 null hippocampal neurons expressing M18Y473D, M18Y473D/P335A or wild-type Munc18-1 as control.

(A) Typical examples of single EPSCs. EPSC amplitude (M18WT: 2.98 ± 0.76 nA, n=11; M18Y473D: 0.042 ± 0.018 nA, n=11, M18Y473D/P335A: 2.02 ± 0.67 nA, n=7, Kruskal-Wallis test, p < 0.0004).

(B) Typical traces of spontaneous release.

(C) mEPSC frequency (M18WT: 8.23 ± 2.29 Hz, n=11; M18Y473D: 0.096 ± 0.056 Hz, n=8, M18Y473D/P335A: 2.18 ± 1.02 Hz, n=11, Kruskal-Wallis test, p = 0.2390), mEPSC amplitude (M18WT: 16.7 ± 1.0 pA, n=11; M18Y473D: 21.6 ± 5.2 pA, n=10, M18Y473D/P335A: 14.8 ± 1.2 pA, n=6, ANOVA, p = 0.1465) and decay time (M18WT: 2.53 ± 0.29 ms, n=11; M18Y473D: 3.79 ± 0.71 ms, n=10, M18Y473D/P335A: 2.85 ± 0.36 pA, n=6, Kruskal-Wallis test, p < 0.0003).

(D) Depression of EPSC amplitude during a 10 Hz train. Inset shows first 4 pulses normalized to the first EPSC.
[BioStudies]_Tyrosine phosphorylation of Munc18-1 inhibits synaptic transmission by preventing SNARE assembly (2017)
Figure 7

Figure 7. Preventing tyrosine phosphorylation on Y473 has no effect on synaptic transmission.

Synaptic transmission in autaptic excitatory munc18-1 neurons expressing M18WT or a non-phosphorylatable Munc18-1 variant, M18Y473F, was tested with whole-cell patch clamp electrophysiology.

(A) Evoked release upon action potential stimulation. Average EPSC amplitude (M18WT: 3.78 ± 0.58 nA, n=22; M18Y473F: 4.10 ± 0.61 nA, n=20, Mann-Whitney U test, p = 0.7915). Typical responses are depicted on the top.

(B) Average mEPSC frequency (M18WT: 5.42 ± 1.86 Hz, n=17; M18Y473F: 4.42 ± 1.01 Hz, n=14, t-test with Welch correction, p = 0.6424), mEPSC amplitude (M18WT: 20.72 ± 0.7 pA, n=17; M18Y473F: 20,5 ± 0.9 pA, n=14, t-test, p = 0.8373) and mEPSC decay time (M18WT: 2.54 ± 0.20 ms, n=17; M18Y473F: 2.46 ± 0.18 ms, n=14, t-test, p = 0.7550). Example traces of spontaneous release are depicted on top.

(C) EPSC depression during 10 Hz stimulation is normal.

(D) Depression of EPSC charge during 40 Hz stimulation is normal. Inset shows the first 5 pulses.

(E) EPSC amplitude recovery two seconds after an RRP depleting 40 Hz train. Average EPSC recovery (M18WT: 82.2 ± 6.7 %, n=17; M18Y473F: 65.5 ± 11.0 %, n=12, t-test, p = 0.1805).

(F) The amount of DSE-triggered EPSC depression was quantified by the ratio of the average EPSC amplitude (taken over 4 pulses given at 0.2 Hz) before or immediately following 10 seconds depolarization to 0mV. Typical EPSCs before and following DSE induction are depicted on the left. Average DSE (M18WT: 0.57 ± 0.04 fold, n=20; M18Y473F: 0.53 ± 0.04 fold, n=16, t-test, p = 0.5227).

(G) PDBu was bath applied during 0.05 Hz stimulation. Maximum potentiation of EPSC amplitude (M18WT: 2.56 ± 0.48 fold, n=7; M18Y473F: 2.82 ± 0.98 fold, n=8, t-test with Welch correction, p = 0.8168).
[BioStudies]_Tyrosine phosphorylation of Munc18-1 inhibits synaptic transmission by preventing SNARE assembly (2017)
Figure 8

Figure 8. Structural modifications to Tyr473 strongly affect synaptic transmission

(A) Using denatured IP, Munc18-1 was pulled-down from cell lysate of HEK293T cells expressing M18WT or M18Y473A together with SFK kinases or an empty vector as control. Munc18-1 was then immunoblotted for tyrosine phosphorylation using the 4G10 antibody. The total amount of Munc18-1 was detected after stripping and reblotting for Munc18-1.

(B-G) Munc18-1 null hippocampal neurons were rescued with wildtype Munc18-1a or a Munc18-1 mutant, Y473A, in which Y473 was replaced with alanine.

(B) Typical confocal images of neurons stained for MAP2, Synaptobrevin/VAMP2 and Munc18-1. Scale bar = 50πm.

(C) Quantification of confocal images. Average synaptic Munc18-1 intensity (M18WT: 389 ± 85 a.u., n=21; M18Y473A: 321 ± 48 a.u., n=20, t-test with Welch correction, p = 0.4868), somatic Munc18-1 intensity (M18WT: 328 ± 49 a.u., n=21; M18Y473A: 245 ± 42 a.u., n=20, t-test, p = 0.2810), synapse number (M18WT: 129 ± 14, n=21; M18Y473A: 159 ± 16, n=20, t-test, p = 0.1548) and dendrite length (M18WT: 0.433 ± 0.028, n=21; M18Y473A: 0.461 ± 0.037, n=20, t-test, p = 0.5473).

(D) Evoked release upon action potential stimulation. Average EPSC amplitude (M18WT: 7.96 ± 0.94 nA, n=30; M18Y473A: 1.44 ± 0.34 nA, n=33, t-test with Welch correction, p < 0.0001). Typical responses are depicted on the right.

(E) Release by hyperosmotic sucrose application (500mM, 3.5sec.) was used to assess the RRP. Left: RRP charge (M18WT: 1.68 ± 0.64 nC, n=13; M18Y473A: 0.27 ± 0.08 nC, n=13, t-test with Welch correction, p = 0.0487). Typical responses are depicted in the middle. Right: vesicular release probability per neuron (EPSC charge / RRP charge). Mean Pves (M18WT: 6.75 ± 0.77%, n=13; M18Y473A: 1.98 ± 0.72%, n=13, t-test, p = 0.0001).

(F) Top: example traces of spontaneous release of single vesicles (mEPSCs). Average mEPSC frequency (M18WT: 20.18 ± 5.18 Hz, n=15; M18Y473A: 0.48 ± 0.15 Hz, n=20, t-test with Welch correction, p = 0.0019), amplitude (M18WT: 26.0 ± 1.7 pA, n=15; M18Y473A: 24.5 ± 1.6 pA, n=20, t-test, p = 0.5334) and decay time (M18WT: 1.98 ± 0.10 ms, n=15; M18Y473A: 2.13 ± 0.17 ms, n=20, t-test with Welch correction, p = 0.4499).

(G) Typical electron microscopy images from rescued autaptic hippocampal Munc18-1 null neurons (scale bar = 100 nm). Neurons expressing M18Y473A have less synaptic vesicles (SV) docked at the active zone. Average number of docked SV (M18WT: 7.63 ± 0.15 SVs; M18Y473A: 5.71 ± 0.28 SVs, multilevel analysis, p < 0.001), total number of SVs (M18WT: 142 ± 11 SVs; M18Y473A: 120 ± 12 SVs, multilevel analysis, p = 0.077), active zone (Munch et al.) length (M18WT: 561 ± 24 nm; M18Y473A: 501 ± 21 nm, multilevel analysis, p = 0.015) and docked SVs per AZ length (M18WT: 0.0140 ± 0.0006 docked SVs/nm AZ; M18Y473A: 0.0117 ± 0.0005 docked SVs/nm AZ, multilevel analysis, p = 0.003). M18WT : N=6 autaptic neurons, n=137 synapses; M18Y473A: N=8 autaptic neurons, n=136 synapses.
[BioStudies]_Tyrosine phosphorylation of Munc18-1 inhibits synaptic transmission by preventing SNARE assembly (2017)
Figure 9

Figure 9. Altered short-term plasticity in neurons expressing M18Y473A.

Autaptic excitatory munc18-1 neurons expressing M18WT or M18Y473A were subjected to stimulation trains of 100 pulses at different frequencies.

(A) Absolute EPSC amplitudes during a 10 Hz train.

(B) EPSC amplitudes during a 10 Hz train normalized to the first EPSC.

(C) Top: example traces of the currents evoked by 40 Hz stimulation. Bottom right: first 5 pulses of the 40 Hz train. Far right: transferred charge during 40 Hz train. Insert shows total charge transferred during entire 40 Hz train (M18WT: 2.63 ± 0.38 nC; M18Y473A: 2.93 ± 0.54 nC, t test, p = 0.6630).

(D) EPSC augmentation is calculated by dividing the EPSC amplitude of a single pulse after a stimulation train by the amplitude of the first EPSC within this train. Mean augmentation after 5 Hz train (M18WT: 0.54 ± 0.05, n=8; M18Y473A: 2.88 ± 0.47, n=10; Unpaired t-test with Welch correction, p = 0.0008), 10 Hz train (M18WT: 0.70 ± 0.10, n=8; M18Y473A: 5.39 ± 0.77, n=10; Unpaired t-test with Welch correction, p = 0.0002) and 40 Hz train (M18WT: 0.93 ± 0.11, n=8; M18Y473A: 8.77 ± 1.52, n=10; Unpaired t-test with Welch correction, p = 0.0006).

(E) A single action potential or sucrose application (500 mM, 3.5 sec.) was given before (naive) or two seconds after HFS (100 pulses at 40 Hz). Average EPSC charge M18WT (Naive: 70.9 ± 19.5 pC, after HFS: 75.4 ± 17.4 pC, n=12, Paired t-test, p = 0.4049). Average EPSC charge M18Y473A (naive: 10.3 ± 4.5 pC, after HFS: 46.2 ± 14.5 pC, n=13, Wilcoxon matched-pairs signed-ranks test, p = 0.0005). Average RRP size M18WT (naive: 1.73 ± 0.69 nC, after HFS: 1.34 ± 0.54 nC, n=12, paired t-test, p = 0.0557) Average RRP size M18Y473A (naive: 0.268 ± 0.075 nC, after HFS: 0.439 ± 0.107 nC, n=13, paired t-test, p = 0.0100). Average Pves M18WT (EPSC charge / RRP charge * 100) (Naive: 7.07 ± 0.76 %, after HFS: 10.6 ± 1.6 %, n=12, paired t-test, p = 0.0201). Average Pves M18Y473A (naive: 1.98 ± 0.72 %, 12.2 ± 2.8 %, n=13, paired t-test, p = 0.0021).

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