The role of extracellular calcium in exo- and endocytosis of synaptic vesicles at the frog motor nerve terminals

Зефиров, А. Л.; Abdrakhmanov, M. M.; Mukhamedyarov, Marat A.; Grigoryev, P N

doi:10.1016/j.neuroscience.2006.08.025

Cited by 41 publications

(32 citation statements)

References 25 publications

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“…The fluorescence of terminal was calculated in arbitrary units (a.u.) as average brightness of all pixels of the part (selected spots) of terminal after subtraction of background fluorescence (Zefirov et al, 2006). The background fluorescence value defined as an average brightness at the segment of terminal without spot (staining vesicle cluster).…”

Section: Methodsmentioning

confidence: 99%

The Role of cGMP-Dependent Signaling Pathway in Synaptic Vesicle Cycle at the Frog Motor Nerve Terminals

Petrov

Giniatullin²,

Ситдикова³

et al. 2008

J. Neurosci.

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The role of cGMP-dependent pathways in synaptic vesicle recycling in motor nerve endings during prolonged high-frequency stimulation was studied at frog neuromuscular junctions using electrophysiological and fluorescent methods. An increase of intracellular cGMP concentration (8-Br-cGMP or 8-pCPT-cGMP) significantly reduced the cycle time for synaptic vesicles through the enhancement of vesicular traffic rate from the recycling pool to the readily releasable pool and acceleration of fast endocytosis. Pharmacological inhibition of soluble guanylate cyclase or protein kinase G slowed down the rate of recycling as well as endocytosis of synaptic vesicles. The results suggest that cGMP-PKG-dependent pathway serves a significant function in the control of vesicular cycle in frog motor terminals.

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Section: Methodsmentioning

confidence: 99%

The Role of cGMP-Dependent Signaling Pathway in Synaptic Vesicle Cycle at the Frog Motor Nerve Terminals

Petrov

Giniatullin²,

Ситдикова³

et al. 2008

J. Neurosci.

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“…Several lines of evidence underscore an important role for Ca 2+ in release site clearance and synaptic vesicle endocytosis [90][91][92] . Indeed, pharmacological manipulations at the Drosophila melanogaster neuromuscular junction 93,94 imply the existence of a specific Ca 2+ channel for synaptic vesicle endocytosis.…”

Section: Calcium Regulationmentioning

confidence: 99%

Protein scaffolds in the coupling of synaptic exocytosis and endocytosis

2011

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Communication between nerve cells largely occurs at chemical synapses -specialized sites of cell-cell contact where electrical signals trigger the exocytic release of neurotransmitter, which in turn activates postsynaptic receptor channels. The efficacy with which such chemical signals are transmitted is crucial for the functioning of the nervous system. Modulation of neurotransmission enables nerve cells to respond to a vast range of stimulus patterns. Synaptic activity can also be tremendously diverse; from the fast synapses of the hippocampus, to slow neuropeptide-containing synapses. Indeed, some signalling pathways are active in the absence of stimulation, such as those involved in the processing of sensory information, which transmit tonically at high rates of up to 100 Hz or more 1,2 .Intriguing questions arise from these facts, including how high rates of neurotransmission can be maintained over long periods of time, and what limits the ability of a given synapse to release neurotransmitter during sustained periods of activity. Recent data indicate that in many synapses, exocytosis of neurotransmitter is coupled to endocytosis, and that synapses have evolved a specialized apparatus of scaffolding proteins to comply with these demands. Such scaffolds aid the temporal and spatial coupling of exocytosis and endocytosis, and are crucial for maintaining rapid neurotransmission during sustained activity 3 .Exocytosis of neurotransmitter is triggered by stimulusinduced calcium influx into the nerve terminal 4,5 and the subsequent fusion of synaptic vesicles with the presynaptic plasma membrane at specialized regions called active zones (BOX 1). Exocytosed synaptic vesicle membrane proteins and lipids in turn are recycled at the endocytic or periactive zone (BOX 1) that surrounds the release site, to restore functional synaptic vesicle pools for reuse and to ensure long-term functionality of the synapse 6-8 (FIG. 1). Depending on the type of synapse and the stimulation frequency, several modes of endocytosis with different time constants -for example, fast and slow endocytosisseem to operate 7,9,10 . Clathrin-mediated endocytosis arguably represents the main pathway of synaptic vesicle endocytosis 6,8,11 , although other modes -for example, fast kiss-and-run exocytosis and endocytosis -could operate in parallel.Although the machineries for exocytic membrane fusion 12,13 and for endocytic retrieval of synaptic vesicle membranes have been studied separately in some detail 6,14 , comparatively little is known about the coupling between exocytosis and endocytosis. Here we synthesize recent data from physiological, morphological and biochemical studies in several model systems into hypothetical models for scaffold-based mechanisms underlying exocytic-endocytic coupling.The synaptic vesicle cycle Synaptic vesicle pools. Some defining features of chemical synapses are the presence of one or several clusters of synaptic vesicles in the presynaptic nerve terminal, and ultrastructural specializations at the pre-and postsy...

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“…Both processes involve significant actin/myosin dynamics (36), calcium (6,44,49), and Dyn-like proteins. For example, Vps1p, a Dyn-like GTPase protein involved in vesicle formation at the Golgi apparatus, was shown also to promote vacuole fusion in yeast (41).…”

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confidence: 99%

Myoferlin is critical for endocytosis in endothelial cells

Bernatchez

Sharma

Kodaman

et al. 2009

American Journal of Physiology-Cell Physiology

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Myoferlin is a member of the ferlin family of proteins that promotes endomembrane fusion with the plasma membrane in muscle cells and endothelial cells. In addition, myoferlin is necessary for the surface expression of vascular endothelial growth factor receptor 2 through the formation of a protein complex with dynamin-2 (Dyn-2). Since Dyn-2 is necessary for the fission of endocytic vesicles from the plasma membrane, we tested the hypothesis that myoferlin may regulates aspects of receptor-dependent endocytosis. Here we show that myoferlin gene silencing decreases both clathrin and caveolae/raft-dependent endocytosis, whereas ectopic myoferlin expression in COS-7 cells increases endocytosis by up to 125%. Interestingly, we have observed that inhibition of Dyn-2 activity or caveolin-1 (Cav-1) expression impairs endocytosis as well as membrane resealing after injury, indicating that Dyn-2 and Cav-1 also participate in both membrane fission and fusion processes. Mechanistically, myoferlin partially colocalizes with Dyn-2 and Cav-1 and forms a protein complex with Cav-1 solubilized from tissue extracts. Together, these data describe a new role for myoferlin in receptor-dependent endocytosis and an overlapping role for myoferlin-Dyn-2-Cav-1 protein complexes in membrane fusion and fission events.

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The role of extracellular calcium in exo- and endocytosis of synaptic vesicles at the frog motor nerve terminals

Cited by 41 publications

References 25 publications

The Role of cGMP-Dependent Signaling Pathway in Synaptic Vesicle Cycle at the Frog Motor Nerve Terminals

The Role of cGMP-Dependent Signaling Pathway in Synaptic Vesicle Cycle at the Frog Motor Nerve Terminals

Protein scaffolds in the coupling of synaptic exocytosis and endocytosis

Myoferlin is critical for endocytosis in endothelial cells

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