scholarly journals Synaptotagmin 1 oligomerization via the juxtamembrane linker regulates spontaneous and evoked neurotransmitter release

2021 ◽  
Vol 118 (48) ◽  
pp. e2113859118
Author(s):  
Kevin C. Courtney ◽  
Jason D. Vevea ◽  
Yueqi Li ◽  
Zhenyong Wu ◽  
Zhao Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lipid Bilayers ◽  
Force Microscopy ◽  
Anionic Phospholipids ◽  
Synaptic Vesicle Exocytosis ◽  
Lysine Residues ◽  
Vesicle Exocytosis ◽  
Synaptotagmin 1 ◽  
Self Association ◽  
Aqueous Conditions

Synaptotagmin 1 (syt1) is a Ca2+ sensor that regulates synaptic vesicle exocytosis. Cell-based experiments suggest that syt1 functions as a multimer; however, biochemical and electron microscopy studies have yielded contradictory findings regarding putative self-association. Here, we performed dynamic light scattering on syt1 in solution, followed by electron microscopy, and we used atomic force microscopy to study syt1 self-association on supported lipid bilayers under aqueous conditions. Ring-like multimers were clearly observed. Multimerization was enhanced by Ca2+ and required anionic phospholipids. Large ring-like structures (∼180 nm) were reduced to smaller rings (∼30 nm) upon neutralization of a cluster of juxtamembrane lysine residues; further substitution of residues in the second C2-domain completely abolished self-association. When expressed in neurons, syt1 mutants with graded reductions in self-association activity exhibited concomitant reductions in 1) clamping spontaneous release and 2) triggering and synchronizing evoked release. Thus, the juxtamembrane linker of syt1 plays a crucial role in exocytosis by mediating multimerization.

scholarly journals Synaptotagmin 1 oligomerization via the juxtamembrane linker regulates spontaneous and evoked neurotransmitter release

2021 ◽  
Author(s):  
Kevin C Courtney ◽  
Yueqi Li ◽  
Jason D Vevea ◽  
Zhenyong Wu ◽  
Zhao Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lipid Bilayers ◽  
Force Microscopy ◽  
Anionic Phospholipids ◽  
Synaptic Vesicle Exocytosis ◽  
Lysine Residues ◽  
Vesicle Exocytosis ◽  
Synaptotagmin 1 ◽  
Self Association ◽  
Aqueous Conditions

Synaptotagmin-1 (syt1) is a Ca2+ sensor that regulates synaptic vesicle exocytosis. Cell-based experiments suggest that syt1 functions as a multimer, however biochemical and electron microscopy studies have yielded contradictory findings regarding putative self-association. Here, we performed dynamic light scattering on syt1 in solution, followed by electron microscopy, and used atomic force microscopy to study syt1 self-association on supported lipid bilayers under aqueous conditions. Ring-like multimers were clearly observed. Multimerization was enhanced by Ca2+ and required anionic phospholipids. Large ring-like structures (~180 nm) were reduced to smaller rings (~30 nm) upon neutralization of a cluster of juxtamembrane lysine residues; further substitution of residues in the second C2-domain completely abolished self-association. When expressed in neurons, syt1 mutants with graded reductions in self-association activity exhibited concomitant reductions in: a) clamping spontaneous release, and b) triggering and synchronizing evoked release. Thus, the juxtamembrane linker of syt1 plays a crucial role in exocytosis by mediating multimerization.

scholarly journals A Complexin/Synaptotagmin 1 Switch Controls Fast Synaptic Vesicle Exocytosis

Cell ◽  
2006 ◽  
Vol 126 (6) ◽  
pp. 1175-1187 ◽  
Author(s):  
Jiong Tang ◽  
Anton Maximov ◽  
Ok-Ho Shin ◽  
Han Dai ◽  
Josep Rizo ◽  
...  
Keyword(s):  
Synaptic Vesicle ◽  
Synaptic Vesicle Exocytosis ◽  
Vesicle Exocytosis ◽  
Synaptotagmin 1

scholarly journals Synaptotagmin-12, a synaptic vesicle phosphoprotein that modulates spontaneous neurotransmitter release

2006 ◽  
Vol 176 (1) ◽  
pp. 113-124 ◽  
Author(s):  
Anton Maximov ◽  
Ok-Ho Shin ◽  
Xinran Liu ◽  
Thomas C. Südhof
Keyword(s):  
Synaptic Vesicle ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Spontaneous Release ◽  
Dependent Protein Kinase ◽  
Synaptic Vesicle Exocytosis ◽  
Vesicle Exocytosis ◽  
Synaptotagmin 1 ◽  
Dependent Protein ◽  
Central Synapses

Central synapses exhibit spontaneous neurotransmitter release that is selectively regulated by cAMP-dependent protein kinase A (PKA). We now show that synaptic vesicles contain synaptotagmin-12, a synaptotagmin isoform that differs from classical synaptotagmins in that it does not bind Ca2+. In synaptic vesicles, synaptotagmin-12 forms a complex with synaptotagmin-1 that prevents synaptotagmin-1 from interacting with SNARE complexes. We demonstrate that synaptotagmin-12 is phosphorylated by cAMP-dependent PKA on serine97, and show that expression of synaptotagmin-12 in neurons increases spontaneous neurotransmitter release by approximately threefold, but has no effect on evoked release. Replacing serine97 by alanine abolishes synaptotagmin-12 phosphorylation and blocks its effect on spontaneous release. Our data suggest that spontaneous synaptic-vesicle exocytosis is selectively modulated by a Ca2+-independent synaptotagmin isoform, synaptotagmin-12, which is controlled by cAMP-dependent phosphorylation.

scholarly journals SV2B Regulates Synaptotagmin 1 by Direct Interaction

2004 ◽  
Vol 279 (50) ◽  
pp. 52124-52131 ◽  
Author(s):  
Diana R. Lazzell ◽  
Roger Belizaire ◽  
Pratima Thakur ◽  
David M. Sherry ◽  
Roger Janz
Keyword(s):  
Synaptic Vesicle ◽  
Direct Interaction ◽  
Synaptic Proteins ◽  
Snare Proteins ◽  
Rod Photoreceptor ◽  
Knock Out ◽  
Synaptic Vesicle Exocytosis ◽  
Vesicle Exocytosis ◽  
Synaptotagmin 1 ◽  
Vesicle Proteins

SV2 proteins are abundant synaptic vesicle proteins expressed in two major (SV2A and SV2B) and one minor (SV2C) isoform. SV2A and SV2B have been shown to be involved in the regulation of synaptic vesicle exocytosis. Previous studies found that SV2A, but not SV2B, can interact with the cytoplasmic domain of synaptotagmin 1, a Ca2+sensor for synaptic vesicle exocytosis. To determine whether SV2B can interact with full-length synaptotagmin 1, we performed immunoprecipitations from brain protein extracts and found that SV2B interacts strongly with synaptotagmin 1 in a detergent-resistant, Ca2+-independent manner. In contrast, an interaction between native SV2A and synaptotagmin 1 was not detectable under these conditions. The SV2B-synaptotagmin 1 complex also contained the synaptic t-SNARE proteins, syntaxin 1 and SNAP-25, suggesting that SV2B may participate in exocytosis by modulating the interaction of synaptotagmin 1 with t-SNARE proteins. Analysis of retinae in SV2B knock-out mice revealed a strong reduction in the level of synaptotagmin 1 in rod photoreceptor synapses, which are unique in that they express only the SV2B isoform. In contrast, other synaptic vesicle proteins were not affected by SV2B knock out, indicating a specific role for SV2B in the regulation of synaptotagmin 1 levels at certain synapses. These experiments suggest that the SV2B-synaptotagmin 1 complex is involved in the regulation of synaptotagmin 1 stability and/or trafficking. This study has demonstrated a new role of SV2B as a regulator of synaptotagmin 1 that is likely mediated by direct interaction of these two synaptic proteins.

Photoelectric Response of Self Assembled Films of Bacterio-Rhodopsin Purple Membrane Integrated on Silicon

2003 ◽  
Vol 774 ◽  
Author(s):  
D. Ricceri ◽  
G. Scicolone ◽  
O. Di Marco ◽  
S. Conoci ◽  
B. Pignataro ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Light Exposure ◽  
Scanning Force Microscopy ◽  
Purple Membrane ◽  
Morphological Properties ◽  
Force Microscopy ◽  
Scanning Force ◽  
Scanning Electron ◽  
Tungsten Lamp

AbstractBacterio-rhodopsin purple membrane (PM) thin films have been prepared by selfassembling (SA) technique. Morphological properties of the layers were inspected by Scanning Electron Microscopy (SEM) and Scanning Force Microscopy (SFM) highlighting the presence of densely packed PM films. Reflectance Uv-vis spectra on these films revealed the typical bR absorption at 570 nm. By using a tungsten lamp illuminations (250-350 mW) chopped at 0.5Hz, photoelectric responses were detected. Differential (light-on and light-off) photocurrent signals of up to 1 μA/cm2 were obtained upon light exposure.

Sign in / Sign up

Export Citation Format

Share Document