Enzymatic digestion of synaptic ribbons in amphibian retinal photoreceptors

Bunt, Ann H.

doi:10.1016/0006-8993(71)90461-6

Cited by 119 publications

(77 citation statements)

References 30 publications

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“…The first is KIF3A, a member of the kinesin superfamily and a component of the kinesin II motor protein holoenzyme (Kondo et al, 1994;Hirokawa and Takemura, 2004;Muresan et al, 1999). The concept of the ribbon as a molecular motor shuttling vesicles to the active zone was originally proposed by Bunt (1971), and the immunocytochemical localization of KIF3A to the ribbon is compatible with this long-standing hypothesis. However, KIF3A is not exclusively localized to synaptic ribbons: it is also found on some synaptic vesicles (Muresan et al, 1998(Muresan et al, , 1999 as well as on many cargo vesicles in the brain, where it mediates anterograde fast axonal transport (Kondo et al, 1994;Yamazaki et al, 1995;Hirokawa and Takemura, 2004).…”

Section: Ribbon Synapse-associated Proteinsmentioning

confidence: 90%

“…Nevertheless, fundamental questions about the function of the ribbon itself are unresolved, of which the main one is just what role does it play in the stimulus-related release of vesicles? The original notion of a conveyor belt formulated by Bunt (1971) seems to be ruled out on kinetic grounds and the finding that ATP hydrolysis is not required for the release of vesicles already in the releasable pool. But even if one accepts that diffusion is sufficient to convey vesicles from the ribbon to the active zone, is there still a signal (or multiple signals) that governs attachment and release of vesicles to their slender tethers?…”

Section: Relation Of Synaptic Release To the Underlying Light-evoked mentioning

confidence: 99%

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Synaptic transmission at retinal ribbon synapses

Heidelberger

Thoreson

Witkovsky

2005

Progress in Retinal and Eye Research

209

231

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The molecular organization of ribbon synapses in photoreceptors and ON bipolar cells is reviewed in relation to the process of neurotransmitter release. The interactions between ribbon synapseassociated proteins, synaptic vesicle fusion machinery and the voltage-gated calcium channels that gate transmitter release at ribbon synapses are discussed in relation to the process of synaptic vesicle exocytosis. We describe structural and mechanistic specializations that permit the ON bipolar cell to release transmitter at a much higher rate than the photoreceptor does, under in vivo conditions. We also consider the modulation of exocytosis at photoreceptor synapses, with an emphasis on the regulation of calcium channels.

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Section: Ribbon Synapse-associated Proteinsmentioning

confidence: 90%

Section: Relation Of Synaptic Release To the Underlying Light-evoked mentioning

confidence: 99%

Synaptic transmission at retinal ribbon synapses

Heidelberger

Thoreson

Witkovsky

2005

Progress in Retinal and Eye Research

209

231

View full text Add to dashboard Cite

show abstract

“…The synaptic ribbons are thought to act as "conveyor belts" that transport a steady stream of synaptic vesicles to their docking sites on the plasma membrane (Bunt, 1971;Gray and Pease, 1971;Raviola and Gilula, 1975) or act as a safety belt to tether vesicles stably in mutual contact and thus facilitate multivesicular release by compound exocytosis (Parsons and Sterling, 2003). Such a specialized function may require unique proteins.…”

Section: Introductionmentioning

confidence: 99%

TworibeyeGenes in Teleosts: The Role of Ribeye in Ribbon Formation and Bipolar Cell Development

Wan¹,

Almers²,

Chen³

2005

J. Neurosci.

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Ribeye is the only known protein specific to synaptic ribbon, but its function is unclear. We show that the teleost fish, Fugu and zebrafish, have two ribeye genes, ribeye a and ribeye b. Whole-mount in situ hybridization revealed that ribeye a is expressed in tissues containing synaptic ribbons, including the pineal gland, inner ear, and retina. Ribeye b is absent in the pineal gland. In the retina, ribeye a is expressed in both photoreceptors and bipolar cells, whereas ribeye b is detected only in photoreceptors. To study the function of Ribeye a in retina, we depleted it by morpholino antisense oligos. Fish deficient in Ribeye a lack an optokinetic response and have shorter synaptic ribbons in photoreceptors and fewer synaptic ribbons in bipolar cells. Their bipolar cells still target Syntaxin-3 proteins to the inner plexiform layer and have abundant vsx1 mRNA. However, they lack large synaptic terminals and show increased apoptosis. Rod bipolar cells are fewer in number and/or deficient in PKC␣. Recovery of Ribeye a levels rescues the optokinetic response, increases the number of PKC␣-positive bipolar cells, and stops apoptosis. We conclude that Ribeye a is important for late steps in bipolar cell development.

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“…1 Synaptic ribbons (SRs) relate to a tonic release of neurotransmitter and are thought to channel synaptic vesicles in an orderly, conveyor-belt fashion to the plasma membrane. 2,3 The rate at which neurotransmitter is released at ribbon synapses is manifold higher than at conventional synapses. [4][5][6][7] In larval (5-6 dpf) zebrafish, ultrastructural analysis of cone pedicles suggested that diurnal alterations of synaptic ribbons are circadian driven.…”

mentioning

confidence: 99%