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Tracking Newly Released Synaptic Vesicle Proteins at Ribbon Active Zones.

ABSTRACT: Clearance of synaptic vesicle proteins from active zones may be rate limiting for sustained neurotransmission. Issues of clearance are critical at ribbon synapses, which continually release neurotransmitters for prolonged periods of time. We used synaptophysin-pHluorin (SypHy) to visualize protein clearance from active zones in retinal bipolar cell ribbon synapses. Depolarizing voltage steps gave rise to small step-like changes in fluorescence likely indicating release of single SypHy molecules from fused synaptic vesicles near active zones. Temporal and spatial fluorescence profiles of individual responses were highly variable, but ensemble averages were well fit by clearance via free diffusion using Monte Carlo simulations. The rate of fluorescence decay of ensemble averages varied with the time and location of the fusion event, with clearance being most rapid at the onset of a stimulus when release rate is the highest.

SUBMITTER: Vaithianathan T

PROVIDER: S-EPMC6598641 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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Tracking Newly Released Synaptic Vesicle Proteins at Ribbon Active Zones.

Vaithianathan Thirumalini T Wollmuth Lonnie P LP Henry Diane D Zenisek David D Matthews Gary G

iScience 20190613

Clearance of synaptic vesicle proteins from active zones may be rate limiting for sustained neurotransmission. Issues of clearance are critical at ribbon synapses, which continually release neurotransmitters for prolonged periods of time. We used synaptophysin-pHluorin (SypHy) to visualize protein clearance from active zones in retinal bipolar cell ribbon synapses. Depolarizing voltage steps gave rise to small step-like changes in fluorescence likely indicating release of single SypHy molecules ...[more]

PMID: 31247447

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