The organization of cytoplasm at the presynaptic active zone of a central nervous system synapse

Landis, Dennis M.D.; Hall, Alison K.; Weinstein, Lori A.; Reese, Thomas S.

doi:10.1016/0896-6273(88)90140-7

Cited by 315 publications

(249 citation statements)

References 34 publications

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“…Numerous in vitro studies have shown that synapsin I acts to cross-link synaptic vesicles with actin filaments in a phosphorylation-dependent manner (B/ihler and Greengard, 1987;Petrucci and Morrow, 1987;Benfenati et al, 1993), a notion supported by electron microscopic observations of short bridging strands between synaptic vesicles and the cytoskeleton in nerve terminals (Landis et al, 1988;Hirokowa et al, 1989). Moreover, recent ultrastructural analyses have shown that the clustering of synaptic vesicles in synaptic terminals of synapsin I knock-out mice is dramatically reduced Takei et al, 1995) in the region >150 nm from the active zone.…”

Section: Discussionmentioning

confidence: 91%

Synaptic vesicle recycling in synapsin I knock-out mice.

Ryan

Chin

et al. 1996

The Journal of Cell Biology

159

127

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Abstract. The synapsins are a family of four neuronspecific phosphoproteins that have been implicated in the regulation of neurotransmitter release. Greengard. 1995. Nature (Lond.). 375:493-497). Here, using the optical tracer FM 1-43, we characterize the details of synaptic vesicle recycling at individual synaptic boutons in hippocampal cell cultures derived from mice lacking synapsin I or wild-type equivalents. These studies show that both the number of vesicles exocytosed during brief action potential trains and the total recycling vesicle pool are significantly reduced in the synapsin I-deficient mice, while the kinetics of endocytosis and synaptic vesicle repriming appear normal.N 'EURONS use regulated secretion at specialized synaptic contacts to transmit information during patterns of electrical activity. Modulation of the probability of exocytosis during action potential firing is thought to underlie major forms of plasticity necessary for nervous system function. Determining the cellular processes that regulate vesicle exocytosis at presynaptic terminals is thus of central interest to neurobiology.Although much progress has been made in identifying important components that participate in synaptic vesicle trafficking and secretion (for reviews see Scheller, 1995;Sudhof, 1995), the unambiguous assignment of these molecules to specific events in the presynaptic terminal remains a major challenge. Striking similarities have emerged upon comparison of molecular composition of presynaptic terminals with those of more general secretory pathways (Bennett and Scheller, 1993). This molecular homology suggests that many parallels exist between all secretory systems at the level of vesicle delivery, docking, fusion, and retrieval. Chemical synapses differ, however, in distinct ways from their secretory counterparts in other parts of the cell or in nonneural tissues. (a) Secretion is highly regulated, providing a tight coupling between action potential stimulation and neurotransmitter release.

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Section: Discussionmentioning

confidence: 91%

Synaptic vesicle recycling in synapsin I knock-out mice.

Ryan

Chin

et al. 1996

The Journal of Cell Biology

159

127

View full text Add to dashboard Cite

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“…8B), except the complex presynaptic cytomatrix, which is most apparent in rapidly frozen, deep-etched preparations viewed under the electron microscope (Landis et al, 1988;Hirokawa et al, 1989). The existence of such compartmentspecific markers within large presynaptic varicosities allows the use of the most attractive features of immunofluorescence microscopy to study subcellular architecture and dynamics within Drosophila motor terminals.…”

Section: Potential Usesmentioning

confidence: 99%

“…Immuno-gold EM may not be a useful way to investigate this hypothesis, because elements of the cytomatrix have been clearly defined only in rapidly frozen, deepetched preparations and are not easily visualized under conventional EM studies. Proposed structural components of this cytomatrix include actin, fodrin, and myosin (Landis et al, 1988;Bernstein and Bamburg, 1989;Hirokawa et al, 1989;Mochida et al, 1994;Burns and Augustine, 1995).…”

Section: Dynamin May Associate With a Presynaptic Cytoskeletonmentioning

confidence: 99%

Traffic of Dynamin within IndividualDrosophilaSynaptic Boutons Relative to Compartment-Specific Markers

et al. 1996

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Presynaptic terminals contain several specialized compartments, which have been described by electron microscopy. We show in an identified Drosophila neuromuscular synapse that several of these compartments-synaptic vesicle clusters, presynaptic plasma membrane, presynaptic cytosol, and axonal cytoskeleton-labeled by specific reagents may be resolved from one another by laser scanning confocal microscopy. Using a panel of compartment-specific markers and Drosophila shibire ts1 mutants to trap an intermediate stage in synaptic vesicle recycling, we have examined the localization and redistribution of dynamin within single synaptic varicosities at the larval neuromuscular junction. Our results suggest that dynamin is not a freely diffusible molecule in resting nerve terminals; rather, it appears localized to synaptic sites by association with yet uncharacterized presynaptic components. In shi ts1 nerve terminals depleted of synaptic vesicles, dynamin is quantitatively redistributed to the plasma membrane. It is not, however, distributed uniformly over presynaptic plasmalemma; instead, fluorescence images show "hot spots" of dynamin on the plasma membrane of vesicle-depleted nerve terminals. We suggest that these dynamin-rich domains may mark the active zones for synaptic vesicle endocytosis first described at the frog neuromuscular junction.

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“…The relationship between protein phosphorylation and exocytotic events in nerve terminals is actively debated [14--18]. The neuron-specific synapsins I and II are localized almost exclusively in regions of the nerve terminal occupied by synaptic vesicles [19,20]. Depolarizationevoked Ca 2÷ entry activates Ca2+-calmodulin-dependent protein kinase II (CaMKII) leading to phosphorylation of the C terminal of synapsin I [21,22] and this has been proposed to facilitate dissociation of synaptic vesicles from the actin cytoskeleton, thus increasing their availability for exocytosis [17,23].…”

Section: Introductionmentioning

confidence: 99%

Phosphorylation of synapsin I and MARCKS in nerve terminals is mediated by Ca²⁺ entry via an Aga‐GI sensitive Ca²⁺ channel which is coupled to glutamate exocytosis

et al. 1994

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Ca 2+ entry is a prerequisite for both exocytosis and the phosphorylation of synapsin I and MARCKS proteins in mammalian cerebrocortical synaptosomes. The novel spider toxin Aga-GI completely blocks KCl-evoked glutamate exocytosis but only partially inhibits KCl-evoked cytoplasmic Ca 2+ elevations, thus revealing at least two pathways for KCl-induced Ca 2+ entry. Aga-GI completely attenuates KCl-induced phosphorylation of synapsin I and MARCKS proteins. We therefore conclude that both exocytosis and the phosphorylation of synapsin I and MARCKS proteins are specifically coupled to Ca 2+ entry via a subset of voltage dependent Ca 2+ channels at the nerve terminal which are sensitive to Aga-GI.

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The organization of cytoplasm at the presynaptic active zone of a central nervous system synapse

Cited by 315 publications

References 34 publications

Synaptic vesicle recycling in synapsin I knock-out mice.

Synaptic vesicle recycling in synapsin I knock-out mice.

Traffic of Dynamin within IndividualDrosophilaSynaptic Boutons Relative to Compartment-Specific Markers

Phosphorylation of synapsin I and MARCKS in nerve terminals is mediated by Ca²⁺ entry via an Aga‐GI sensitive Ca²⁺ channel which is coupled to glutamate exocytosis

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The organization of cytoplasm at the presynaptic active zone of a central nervous system synapse

Cited by 315 publications

References 34 publications

Synaptic vesicle recycling in synapsin I knock-out mice.

Synaptic vesicle recycling in synapsin I knock-out mice.

Traffic of Dynamin within IndividualDrosophilaSynaptic Boutons Relative to Compartment-Specific Markers

Phosphorylation of synapsin I and MARCKS in nerve terminals is mediated by Ca2+ entry via an Aga‐GI sensitive Ca2+ channel which is coupled to glutamate exocytosis

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Phosphorylation of synapsin I and MARCKS in nerve terminals is mediated by Ca²⁺ entry via an Aga‐GI sensitive Ca²⁺ channel which is coupled to glutamate exocytosis