scholarly journals Analysis of protein phosphorylation in nerve terminal reveals extensive changes in active zone proteins upon exocytosis

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Mahdokht Kohansal-Nodehi ◽  
John JE Chua ◽  
Henning Urlaub ◽  
Reinhard Jahn ◽  
Dominika Czernik
Keyword(s):  
Active Zone ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Wistar Rats ◽  
Nerve Terminals ◽  
Calcium Dependent ◽  
Presynaptic Plasticity ◽  
Presynaptic Plasma Membrane ◽  
Quantitative Phosphoproteomics ◽  
Presynaptic Proteins

Neurotransmitter release is mediated by the fast, calcium-triggered fusion of synaptic vesicles with the presynaptic plasma membrane, followed by endocytosis and recycling of the membrane of synaptic vesicles. While many of the proteins governing these processes are known, their regulation is only beginning to be understood. Here we have applied quantitative phosphoproteomics to identify changes in phosphorylation status of presynaptic proteins in resting and stimulated nerve terminals isolated from the brains of Wistar rats. Using rigorous quantification, we identified 252 phosphosites that are either up- or downregulated upon triggering calcium-dependent exocytosis. Particularly pronounced were regulated changes of phosphosites within protein constituents of the presynaptic active zone, including bassoon, piccolo, and RIM1. Additionally, we have mapped kinases and phosphatases that are activated upon stimulation. Overall, our study provides a snapshot of phosphorylation changes associated with presynaptic activity and provides a foundation for further functional analysis of key phosphosites involved in presynaptic plasticity.

scholarly journals Neurotransmitter Release Site Replenishment and Presynaptic Plasticity

2020 ◽  
Vol 22 (1) ◽  
pp. 327
Author(s):  
Sumiko Mochida
Keyword(s):  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
High Speed ◽  
Release Site ◽  
Short Term ◽  
Short Term Plasticity ◽  
Multiple Protein ◽  
Presynaptic Plasticity ◽  
Presynaptic Plasma Membrane ◽  
Ca2 Channels

An action potential (AP) triggers neurotransmitter release from synaptic vesicles (SVs) docking to a specialized release site of presynaptic plasma membrane, the active zone (AZ). The AP simultaneously controls the release site replenishment with SV for sustainable synaptic transmission in response to incoming neuronal signals. Although many studies have suggested that the replenishment time is relatively slow, recent studies exploring high speed resolution have revealed SV dynamics with milliseconds timescale after an AP. Accurate regulation is conferred by proteins sensing Ca2+ entering through voltage-gated Ca2+ channels opened by an AP. This review summarizes how millisecond Ca2+ dynamics activate multiple protein cascades for control of the release site replenishment with release-ready SVs that underlie presynaptic short-term plasticity.

Neurotransmitter Release

2017 ◽  
Author(s):  
Peggy Mason
Keyword(s):  
Plasma Membrane ◽  
Synaptic Vesicle ◽  
Active Zone ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Synaptic Cleft ◽  
Fusion Pore ◽  
Synaptic Membrane ◽  
Specialized Region ◽  
Synaptic Vesicle Fusion

The biochemical and physiological processes of neurotransmitter release from an active zone, a specialized region of synaptic membrane, are examined. Synaptic vesicles containing neurotransmitters are docked at the active zone and then primed for release by SNARE complexes that bring them into extreme proximity to the plasma membrane. Entry of calcium ions through voltage-gated calcium channels triggers synaptic vesicle fusion with the synaptic terminal membrane and the consequent diffusion of neurotransmitter into the synaptic cleft. Release results when the fusion pore bridging the synaptic vesicle and plasma membrane widens and neurotransmitter from the inside of the synaptic vesicle diffuses into the synaptic cleft. Membrane from the active zone membrane is endocytosed, and synaptic vesicle proteins are then reassembled into recycled synaptic vesicles, allowing for more rounds of neurotransmitter release.

scholarly journals Fife organizes synaptic vesicles and calcium channels for high-probability neurotransmitter release

2016 ◽  
Vol 216 (1) ◽  
pp. 231-246 ◽  
Author(s):  
Joseph J. Bruckner ◽  
Hong Zhan ◽  
Scott J. Gratz ◽  
Monica Rao ◽  
Fiona Ukken ◽  
...  
Keyword(s):  
Neural Plasticity ◽  
Active Zone ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Motor Behavior ◽  
Molecular Organization ◽  
Electrophysiological Studies ◽  
Circuit Function ◽  
Synaptic Vesicle Release ◽  
Ca2 Channels

The strength of synaptic connections varies significantly and is a key determinant of communication within neural circuits. Mechanistic insight into presynaptic factors that establish and modulate neurotransmitter release properties is crucial to understanding synapse strength, circuit function, and neural plasticity. We previously identified Drosophila Piccolo-RIM-related Fife, which regulates neurotransmission and motor behavior through an unknown mechanism. Here, we demonstrate that Fife localizes and interacts with RIM at the active zone cytomatrix to promote neurotransmitter release. Loss of Fife results in the severe disruption of active zone cytomatrix architecture and molecular organization. Through electron tomographic and electrophysiological studies, we find a decrease in the accumulation of release-ready synaptic vesicles and their release probability caused by impaired coupling to Ca2+ channels. Finally, we find that Fife is essential for the homeostatic modulation of neurotransmission. We propose that Fife organizes active zones to create synaptic vesicle release sites within nanometer distance of Ca2+ channel clusters for reliable and modifiable neurotransmitter release.

scholarly journals Presynaptic Calcium Channels

2019 ◽  
Vol 20 (9) ◽  
pp. 2217 ◽  
Author(s):  
Sumiko Mochida
Keyword(s):  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Neuronal Firing ◽  
Regulatory Proteins ◽  
Channel Modulation ◽  
Signaling Complex ◽  
Presynaptic Plasticity ◽  
Presynaptic Calcium ◽  
Ca2 Channels ◽  
Α1 Subunit

Presynaptic Ca2+ entry occurs through voltage-gated Ca2+ (CaV) channels which are activated by membrane depolarization. Depolarization accompanies neuronal firing and elevation of Ca2+ triggers neurotransmitter release from synaptic vesicles. For synchronization of efficient neurotransmitter release, synaptic vesicles are targeted by presynaptic Ca2+ channels forming a large signaling complex in the active zone. The presynaptic CaV2 channel gene family (comprising CaV2.1, CaV2.2, and CaV2.3 isoforms) encode the pore-forming α1 subunit. The cytoplasmic regions are responsible for channel modulation by interacting with regulatory proteins. This article overviews modulation of the activity of CaV2.1 and CaV2.2 channels in the control of synaptic strength and presynaptic plasticity.

scholarly journals Rab3A Is Involved in Transport of Synaptic Vesicles to the Active Zone in Mouse Brain Nerve Terminals

2001 ◽  
Vol 12 (10) ◽  
pp. 3095-3102 ◽  
Author(s):  
A.G. Miriam Leenders ◽  
Fernando H. Lopes da Silva ◽  
Wim E.J.M. Ghijsen ◽  
Matthijs Verhage
Keyword(s):  
Active Zone ◽  
Synaptic Vesicles ◽  
Nerve Terminals ◽  
Null Mutant ◽  
Rab Protein ◽  
Fusion Probability ◽  
Intracellular Compartments ◽  
Null Mutant Mice ◽  
Dependent Transport ◽  
Activity Dependent

The rab family of GTP-binding proteins regulates membrane transport between intracellular compartments. The major rab protein in brain, rab3A, associates with synaptic vesicles. However, rab3A was shown to regulate the fusion probability of synaptic vesicles, rather than their transport and docking. We tested whether rab3A has a transport function by analyzing synaptic vesicle distribution and exocytosis in rab3A null-mutant mice. Rab3A deletion did not affect the number of vesicles and their distribution in resting nerve terminals. The secretion response upon a single depolarization was also unaffected. In normal mice, a depolarization pulse in the presence of Ca2+ induces an accumulation of vesicles close to and docked at the active zone (recruitment). Rab3A deletion completely abolished this activity-dependent recruitment, without affecting the total number of vesicles. Concomitantly, the secretion response in the rab3A-deficient terminals recovered slowly and incompletely after exhaustive stimulation, and the replenishment of docked vesicles after exhaustive stimulation was also impaired in the absence of rab3A. These data indicate that rab3A has a function upstream of vesicle fusion in the activity-dependent transport of synaptic vesicles to and their docking at the active zone.

scholarly journals Synaptic vesicles transiently dock to refill release sites

2018 ◽  
Author(s):  
Grant F Kusick ◽  
Morven Chin ◽  
Sumana Raychaudhuri ◽  
Kristina Lippmann ◽  
Kadidia P Adula ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Active Zone ◽  
Synaptic Vesicles ◽  
Electrical Field Stimulation ◽  
Dependent Manner ◽  
Single Action ◽  
Calcium Dependent ◽  
Synaptic Vesicle Exocytosis ◽  
Vesicle Exocytosis ◽  
Asynchronous Release

AbstractSynaptic vesicles fuse with the plasma membrane to release neurotransmitter following an action potential, after which new vesicles must ‘dock’ to refill vacated release sites. To capture synaptic vesicle exocytosis at cultured mouse hippocampal synapses, we induced single action potentials by electrical field stimulation then subjected neurons to high-pressure freezing to examine their morphology by electron microscopy. During synchronous release, multiple vesicles can fuse at a single active zone; this multivesicular release is augmented by increasing extracellular calcium. Fusions during synchronous release are distributed throughout the active zone, whereas fusions during asynchronous release are biased toward the center of the active zone. Immediately after stimulation, the total number of docked vesicles across all synapses decreases by ∼40%. Between 8 and 14 ms, new vesicles are recruited to the plasma membrane and fully replenish the docked pool in a calcium-dependent manner, but docking of these vesicles is transient and they either undock or fuse within 100 ms. These results demonstrate that recruitment of synaptic vesicles to release sites is rapid and reversible.

scholarly journals RNA editing of CAPS1 regulates synaptic vesicle organization, release and retrieval

2017 ◽  
Author(s):  
Randi J. Ulbricht ◽  
Sarah J. Sun ◽  
Claire E. DelBove ◽  
Kristina E. Kitko ◽  
Saad C. Rehman ◽  
...  
Keyword(s):  
Rna Editing ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Protein Isoforms ◽  
Editing Event ◽  
Calcium Dependent ◽  
Presynaptic Vesicle ◽  
Vesicle Pool ◽  
Fine Tune

ABSTRACTCalcium-dependent activator protein for secretion 1 (CAPS1) facilitates the docking and priming of synaptic and dense core vesicles. A conserved hairpin structure in the CAPS1 pre-mRNA allows an post-transcriptional adenosine-to-inosine RNA editing event to alter a genomically-encoded glutamate to a glycine codon. Functional comparisons of CAPS1 protein isoforms in primary hippocampal neurons show that elevation of edited CAPS1 isoforms facilitates presynaptic vesicle clustering and turnover. Conversely, non-edited CAPS1 isoforms slow evoked release, increase spontaneous fusion, and loosen the clustering of synaptic vesicles. Therefore, CAPS1 editing promotes organization of the vesicle pool in a way that is beneficial for evoked release, while non-edited isoforms promote more lax vesicle organization that widens distribution, attenuates evoked release and eases the control of spontaneous fusion. Overall, RNA editing of CAPS1 is a mechanism to fine tune neurotransmitter release.IMPACT STATEMENTPost-transcriptional RNA editing of CAPS1 is a mechanism to regulate neurotransmitter release from synaptic vesicles.

scholarly journals Control of neurotransmitter release by two distinctmembrane-binding faces of the Munc13-1 C­1C2B region

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Marcial Camacho ◽  
Bradley Quade ◽  
Thorsten Trimbuch ◽  
Junjie Xu ◽  
Levent Sari ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Point Mutations ◽  
Short Term ◽  
In Vitro Reconstitution ◽  
Presynaptic Plasticity ◽  
Hippocampal Cultures

Munc13-1 plays a central role in neurotransmitter release through its conserved C-terminal region, which includes a diacyglycerol (DAG)-binding C1 domain, a Ca2+/PIP2-binding C2B domain, a MUN domain and a C2C domain. Munc13-1 was proposed to bridge synaptic vesicles to the plasma membrane through distinct interactions of the C­1C2B region with the plasma membrane: i) one involving a polybasic face that is expected to yield a perpendicular orientation of Munc13-1 and hinder release; and ii) another involving the DAG-Ca2+-PIP2-binding face that is predicted to result in a slanted orientation and facilitate release. Here we have tested this model and investigated the role of the C­1C2B region in neurotransmitter release. We find that K603E or R769E point mutations in the polybasic face severely impair Ca2+-independent liposome bridging and fusion in in vitro reconstitution assays, and synaptic vesicle priming in primary murine hippocampal cultures. A K720E mutation in the polybasic face and a K706E mutation in the C2B domain Ca2+-binding loops have milder effects in reconstitution assays and do not affect vesicle priming, but enhance or impair Ca2+-evoked release, respectively. The phenotypes caused by combining these mutations are dominated by the K603E and R769E mutations. Our results show that the C1-C2B region of Munc13-1 plays a central role in vesicle priming and support the notion that two distinct faces of this region control neurotransmitter release and short-term presynaptic plasticity.

scholarly journals Physical and functional interaction of the active zone proteins, CAST, RIM1, and Bassoon, in neurotransmitter release

2004 ◽  
Vol 164 (2) ◽  
pp. 301-311 ◽  
Author(s):  
Etsuko Takao-Rikitsu ◽  
Sumiko Mochida ◽  
Eiji Inoue ◽  
Maki Deguchi-Tawarada ◽  
Marie Inoue ◽  
...  
Keyword(s):  
Synaptic Transmission ◽  
Active Zone ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Ternary Complex ◽  
Binding Region ◽  
Functional Interaction ◽  
Cervical Ganglion ◽  
Ganglion Neurons ◽  
The Brain

We have recently isolated a novel cytomatrix at the active zone (CAZ)–associated protein, CAST, and found it directly binds another CAZ protein RIM1 and indirectly binds Munc13-1 through RIM1; RIM1 and Munc13-1 directly bind to each other and are implicated in priming of synaptic vesicles. Here, we show that all the CAZ proteins thus far known form a large molecular complex in the brain, including CAST, RIM1, Munc13-1, Bassoon, and Piccolo. RIM1 and Bassoon directly bind to the COOH terminus and central region of CAST, respectively, forming a ternary complex. Piccolo, which is structurally related to Bassoon, also binds to the Bassoon-binding region of CAST. Moreover, the microinjected RIM1- or Bassoon-binding region of CAST impairs synaptic transmission in cultured superior cervical ganglion neurons. Furthermore, the CAST-binding domain of RIM1 or Bassoon also impairs synaptic transmission in the cultured neurons. These results indicate that CAST serves as a key component of the CAZ structure and is involved in neurotransmitter release by binding these CAZ proteins.

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